Relationship between lightning and model simulated microphysical ...

Nat. Hazards Earth Syst. Sci., 9, 1719–1726, 2009 www.nat-hazards-earth-syst-sci.net/9/1719/2009/ © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.

Natural Hazards and Earth System Sciences

Relationship between lightning and model simulated microphysical parameters over the central and eastern Mediterranean D. K. Katsanos, K. Lagouvardos, and V. Kotroni National Observatory of Athens, Institute for Environmental Research and Sustainable Development, Athens, Greece Received: 15 April 2009 – Revised: 4 September 2009 – Accepted: 21 September 2009 – Published: 21 October 2009

Abstract. In this study the relationship between lightning and simulated microphysical parameters of clouds, is examined. In order to investigate such a relationship, a number of cases with significant lightning activity that occurred during the wet period of the year over the central and eastern Mediterranean have been selected, based on the lightning activity reported by the ZEUS lighting detection network, operated by the National Observatory of Athens. For the same cases, simulations with the non-hydrostatic MM5 model were performed with the aim of reproducing the dynamical and microphysical parameters associated with the weather systems that produced lightning. The analysis showed that the temporal distribution of convective rainfall is not well correlated with that of lightning, while on the contrary, the temporal distribution of the simulated concentrations of solid hydrometeors correlates well with lightning and there is also a general coincidence of their maxima. Further, it was shown that the best correlation was found during the development stage of the storms, while during the decay phase the number of lightning decreases much faster that the simulated concentrations of solid hydrometeors.

1

Introduction

The Mediterranean Sea, although a relatively small and rather warm body of water, is considered as one of the most important centers of electrical activity in the northern hemisphere during the cold period of the year, as this is implied by the studies made by Orville (1981), Christian et al. (1999) and Holt et al. (2001). In more recent studies, Price and Federmesser (2006) based on TRMM satellite data over the Mediterranean, concluded that more than 75% of rain and Correspondence to: D. K. Katsanos ([email protected])

lightning in the region occur during the period from October to March, while more than 90% of the thunderstorms occur over the sea. Furthermore, lightning activity presents its maximum during November, while the maximum of precipitation occurs during December. In a recent study, Katsanos et al. (2007a) have shown that during the wet period of the year (e.g. autumn and winter for the area of the Mediterranean) the lightning activity occurs over the maritime area and near the coasts almost delineating the Mediterranean coastline. The significant atmospheric electrical activity over the Mediterranean Sea, has motivated many researchers to investigate, among other issues, the relationship between lightning and parameters such as rainfall, or microphysical characteristics of clouds. In a number of studies devoted to the investigation of the relationship between lightning activity and microphysical parameters of clouds, such as those by Toracinta and Zipser (2001), Defer et al. (2005) and Katsanos et al. (2007b), satellite measurements in the microwave region of the spectrum, and especially measurements in the 85 GHz frequency, have been used. According to our present understanding of microphysical charging mechanisms, the presence of ice particles is a necessary component for the electrification processes within clouds that lead to lightning occurrence (Rakov and Uman, 2003). Also, strong updrafts can activate aerosols and enhance homogeneous freezing in order to produce more cloud particles near the top of the cloud. Thus, lighting activity seems to be related to the amount of small ice that is present at the cloud top (Sherwood et al., 2006). According to Deierling and Petersen (2008) the presence of a large amount of hydrometeors in the mixed ice phase region, produced by “high” updraft speeds, computed by ground – based and dual polarimetric radar observations, results to higher number of collisions between graupel and ice crystals with subsequent charge separation that can lead to lightning production. Also, they found that there is a strong correlation between precipitation ice mass and mean total lightning activity.

Published by Copernicus Publications on behalf of the European Geosciences Union.

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D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean

In these studies it was shown that low values of brightness temperature are associated with lightning activity and therefore this kind of data could be used as proxies for estimating the possibility of lightning occurrence. Recently Pessi and Businger (2009) showed a very good correlation between satellite estimated convective rainfall, derived by the Precipitation Radar (PR) onboard TRMM that measures at 13.8 GHz and lightning, giving motivation to investigate the possibility of a relationship between those two parameters. Most of the studies that investigate the relationship between convective precipitation and lightning, are devoted to tropical thunderstorms, while there is a lack of such studies over the Mediterranean. Since satellites can only provide data during their overpass above a specific area, it is difficult to cover adequately all cases that occur and to study their temporal evolution. As direct measurements of ice content are sparse, this analysis could be based on simulated fields provided by mesoscale atmospheric numerical models, as discussed in the following section. Such an approach was recently used by Lagouvardos and Kotroni (2007) concluding that spaceborne measurements can be used for the observation of mid-latitude weather systems as well as for the validation of high resolution model results. The rest of the paper is organized as follows: Sect. 2 presents the data and the methodology used, while Sect. 3 discusses the comparison between MM5 model simulated fields and lightning activity. Section 4 is devoted to the concluding remarks and prospects of this study.

2 2.1

Data and methodology Lightning Data

The analysis and the selection of cases are based on lightning data provided by the ZEUS network and simulations performed with the non-hydrostatic model MM5. A number of cases, most of them lasting one day, with significant amount of recorded lightning flashes by ZEUS during autumn and winter (2005–2008) over the central and eastern Mediterranean, were selected in order to perform the comparison with the simulated fields by MM5. The ZEUS long-range lightning detection system, operated by the National Observatory of Athens, is based on detection of sferics – the impulsive radio noise emitted by a lightning strike – in the Very Low Frequency (VLF) spectrum between 7 and 15 kHz. The ZEUS system consists of a network of six VLF receivers located around the periphery of Europe (Birmingham in UK, Roskilde in Denmark, Iasi in Romania, Larnaka in Cyprus, Athens in Greece and Lisbon in Portugal). Each receiver reports the vertical electric field as a function of time which represents the sferic’s waveform and includes a time stamp synchronized to GPS time. At each receiver site an identification algorithm is executed Nat. Hazards Earth Syst. Sci., 9, 1719–1726, 2009

that detects a probable sferics candidate, excludes weak signal and noise and is capable of capturing up to 70 sferics per second. Then the lightning location is retrieved (at the central station of the network) using the arrival time difference triangulation technique. Further details on ZEUS network are given in Kotroni and Lagouvardos (2008). The detection efficiency and location error of the ZEUS lightning detection network has been evaluated recently against collocated data provided by the LINET detection network (Lagouvardos et al., 2009). The area of comparison was limited over a part of Central-Western Europe, where the dense LINET network can guarantee a high detectability of lightning strokes with location accuracy of the order of a few hundred meters. The analysis showed that the location error of ZEUS was calculated to be ∼6.8 km, while the detection efficiency was ∼25%, with a characteristic under-prediction during nighttime. 2.2

MM5 model configuration

The MM5 model is a non-hydrostatic, primitive equations model (Dudhia, 1993). Several physical parameterization schemes, are available in the model for the boundary layer, the radiative transfer, the microphysics and the cumulus convection. For this study, from the multitude of available schemes the following have been selected: the scheme by Hong and Pan (1996) for the boundary layer, the KainFritsch (1993) for cumulus convection and the Schultz (1995) for explicit microphysics. The last two schemes have been proved to provide the most skillful precipitation forecasts in the eastern Mediterranean (Kotroni and Lagouvardos, 2001). Two domains are used for the model simulations. The coarse domain covers most of Europe, up to 60◦ N, North Africa and the Middle East with a horizontal resolution of 24 km and 220×140 grid points. The inner domain covers a part of the central and eastern Mediterranean with a horizontal resolution of 8 km and 220×148 grid points. In the vertical, 31 sigma levels are defined from the surface up to 100 hPa. ECMWF analyses at 0.5 degrees resolution have been used to initialize the model and to nudge the boundaries of the coarse domain during the simulation period. In a recent study, Katsanos et al. (2008) presented the first results of a case simulated by MM5 model, showing that there is a good agreement between forecasted fields of ice phase cloud elements and lightning activity, mostly regarding their temporal evolution. These results gave the motivation for a further study. The output fields that are used for the comparison in the present study are the vertically integrated mixing ratios of ice, snow and graupel, the rainfall, both total and convective. Each simulation is initialized at 00:00 UTC and lasts 24 h, and for some exceptions 48 h, with outputs at 1-h intervals. Ten cases with significant lightning activity, mainly in the central Mediterranean, which occurred from 2005 to 2008, have been simulated. The selection of cases was based on the number of daily lightning flashes observed www.nat-hazards-earth-syst-sci.net/9/1719/2009/

D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean over the maritime area of central and eastern Mediterranean. The selected days satisfied a criterion of at least 20 000 observed lightning flashes over the selected area, during 24 h. Among these ten cases, for six cases the model was able to reproduce well the temporal and spatial evolution of the weather system, in accordance with ZEUS lightning observations. In the following paragraphs two representative cases with heavy rainfall and intense lightning are presented in detail, later on, all six cases are discussed. It should be mentioned that the four remaining cases that are not analyzed in the following have been considered as not successful simulations, as they failed to reproduce a convective activity coherent (both spatially and temporally) with the observations.

3 3.1

Results – discussion Case study (a)

On 13 December 2005 at 06:00 UTC, a barometric low with a central pressure of 1005 hPa was located over the area northwest of the Gulf of Sidra. The pressure low deepened to 997 hPa at 12:00 UTC, and reached the lowest central pressure of 992 hPa by the end of the day, just offshore the Tunisian coast. The pressure low was accompanied by a cold front moving slowly northeastwards. Within 24 h an amount of almost 35 000 CG lightning flashes was recorded. The corresponding TRMM overpass showed a band of low Polarization Corrected Temperature (PCT) values (not shown) expanding from Sicily southwards to the Sidra Gulf denoting the cold front position. Figure 1a presents the convective precipitation (in mm) with the surface pressure (in hPa), as simulated by the MM5 model inner grid (the domain shown represents the extent of MM5 inner domain with 8-km resolution), at 12:00 UTC. The simulated low pressure centre of 996 hPa is located southwest of Sicily. The model has positioned the low pressure centre almost 1◦ to the west of its actual position. Significant lightning activity was recorded during the event (Fig. 1b). The convective precipitation field shows that rainfall and lightning are present in the same area during the same time period; however convective rain is still forecasted in areas that no lightning activity is recorded. The highest concentrations of simulated solid hydrometeors (not shown) were found shifted to the west of the area where lightning activity was recorded by ZEUS system. Figure 1c presents the cross section of the vertical velocity (in ms−1 ) along the 35◦ N latitude line and from 12◦ E to 18◦ E shown in Fig. 1b. It can be seen that updrafts are present in the same area where also lightning is recorded. Figure 1d shows the vertical distribution of all ice phase elements (ice + graupel + snow) and only graupel separately across the same line as in Fig. 1c. It is shown that ice particles are present down to relatively low levels (800 hPa), with graupel (black contour line) being the dominant hydromewww.nat-hazards-earth-syst-sci.net/9/1719/2009/

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teor at the lower levels of the cloud. Ice on the other hand, is mostly present at the upper levels of the cloud (not shown). The temporal evolution of the lightning activity with the convective precipitation and ice particle concentrations, are presented in the following. This is done by integrating both fields within a box with dimensions 5◦ ×5◦ including the area from 11◦ E to 16◦ E and from 33.5◦ N to 38.5◦ N (denoted with a dotted box in Fig. 1b) in order to account for the “shift” of the simulated fields. Within this box, the number (sum) of lightning flashes was calculated along with the maximum values of convective rainfall and the average profile of the integrated mixing ratio of ice+graupel+snow, derived from the MM5 simulations. The results concerning the comparison between convective precipitation and lightning, are shown in Fig. 1e. It can be seen that there is coherence in the temporal evolution of lightning activity and model calculated convective precipitation up to 15:00 UTC, with coincidence of the time of both maxima, but also coherence in the decrease of both fields from the time of their peak at 10:00 UTC up to the minima at 13:00 UTC. From 15:00 UTC and on, the two fields do not evolve in the same way as the lightning activity decreases further while, on the contrary, the convective precipitation increases. It is obvious that convective rainfall is present, according to the model forecasted fields, both before and after the period of lightning occurrence. In Fig. 1f the comparison between the temporal evolution of the average profile of the integrated mixing ratio of ice + graupel + snow and lightning activity is presented, for the hours from 06:00 to 18:00 UTC. The mixing ratio presents almost a “bell” shaped distribution with the maximum values from 07:00 to 12:00 UTC, which coincides with the time interval of the fast low pressure deepening. As expected, the building up of the lightning activity time lags the increase in the mixing ratio of ice + snow + graupel, although here the time lag of about one to two hours is considered larger than what is usually observed. This is partly attributed to the fact that, while lightning observations are continuous, the model outputs are at hourly intervals and also to a delay of the model itself to reproduce the convective and microphysical properties of the event. Nevertheless, it should be noted that the two curves coincide at their maximum which occurs at 10:00 UTC. Then, within the period of decrease of the mixing ratio, the lightning activity also decreases with a faster rate. Unlike the comparison of the lightning with the convective precipitation, the temporal evolution of lightning actually seems to be very well correlated with the presence of the ice phase species. 3.2

Case study (b)

On 30 October 2006 at 06:00 UTC, a barometric low with a central pressure of 1003 hPa was located over the region of the Aegean Sea, deepening throughout the day to 998 hPa, moving southwards and giving heavy rainfall in central and Nat. Hazards Earth Syst. Sci., 9, 1719–1726, 2009

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Fig. 1. (a) convective precipitation (mm) and surface pressure (in hPa with 2 hPa interval) as forecasted by MM5 at 12:00 UTC, (b) lightning Figure 1. (a) convective precipitation (mm) −1 surface pressure (in hPa with 2 hPa interval) as activity, (c) cross section (y axis in hPa) of vertical velocity (in ms andwith 0.2 ms−1 interval) across the line shown in (b), (d) cross section MM5(shaded), at 12:00 only UTC,graupel (b) lightning axis in in hPa) of across verticalthe line shown in (y axis in hPa) of iceforecasted + graupel by + snow (black activity, contour) (c) andcross only section ice (red (y contour) g/kg, (b), temporal evolution of: (e) convective precipitation with lightning activity and (f) ice + graupel + snow with lightning for the area -1 -1 of velocity (in ms with 0.2 ms interval) across the line shown in (b), (d) cross section (y axis in hPa)activity, within the box in (b). ice+graupel+snow (shaded), only graupel (black contour) and only ice (red contour) in g/kg, across the line shown inby (b),a temporal evolution of:24 (e)hconvective precipitation with lightning activity (f) eastern Greece, accompanied cold front. Within low levels, with graupel being again theand dominant type at the ice+graupel+snow withflashes lightning activity, for the area within the box in (b). an amount of almost 22 000 lightning was recorded. lower parts of the cloud and snow or ice at the higher parts, Spatial comparison (Fig. 2a and b) shows the presence of with this distribution being favorable for creating charge sepsimulated convective rainfall in areas without lightning acaration necessary for cloud electrification and lightning oc14 tivity. Indeed convective rainfall in this case is forecasted currence. outspread in a large area, while lightning is recorded in a The corresponding figure for the comparison of convecmore limited area. tive rainfall with lightning activity shows also a good agreement, regarding the forecast of rainfall at the same time that The cross section of forecasted vertical velocity (Fig. 2c) lightning is recorded (Fig. 2e), however as in the previous shows again the presence of updrafts in the area of lightning, case, convective precipitation is forecasted before and after however not very strong (0.5 ms−1 ) in comparison with the any lightning is observed. previous case. The vertical distribution of solid hydrometeors (Fig. 2d) shows that the model forecasts their presence in

Nat. Hazards Earth Syst. Sci., 9, 1719–1726, 2009

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D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean

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2. (a) convective precipitation (mm) andwith surface hPa with 2byhPa interval) Fig. 2. (a) convectiveFigure precipitation (mm) and surface pressure (in hPa 2 hPapressure interval)(in as forecasted MM5 at 12:00asUTC, (b) lightning −1 with 0.2 ms−1 interval) across the line shown in (b), (d) cross section activity, (c) cross section (y axis in hPa) of vertical velocity (in ms forecasted by MM5 at 12:00 UTC, (b) lightning activity, (c) cross section (y axis in hPa) of vertical (y axis in hPa) of ice + graupel + snow (shaded),-1only graupel (black contour) and only ice (red contour) in g/kg, across the line shown in 0.2 ms interval) the activity line shown cross section axislightning in hPa) of velocity ms-1 with precipitation (b), temporal evolution of: (e)(inconvective withacross lightning andin (f)(b), ice (d) + graupel + snow(ywith activity, for the area within the box in (b).ice+graupel+snow (shaded) , only graupel (black contour) and only ice (red contour) in g/kg, across the line shown in (b), temporal evolution of: (e) convective precipitation with lightning activity and (f) ice+graupel+snow withoflightning activity, case, for the area3.3 withinDiscussion the box in (b). In agreement with the discussion the previous there is also a very good agreement between the temporal variation of model integrated ice, graupel and snow with In this section emphasis is given to the investigation of the the amount of observed lightning flashes throughout the day 15 correlation between the simulated solid hydrometeor concen(Fig. 2f), for the area delimited by the box shown in Fig. 2b, trations and the observed lightning. For that purpose, the while there are slight differences in the occurrence times of analysis is extended to all six cases and the results are shown the maximal values and in the rate of decrease, with the lightin Figs. 3 and 4. All cases initially selected had more or ning activity decreasing more rapidly. less the same characteristics from a synoptic point of view: frontal depressions that developed over the sea, mainly during winter and autumn, which were moving eastwards affecting S. Italy and Greece with intense phenomena like thunderstorms with heavy rain and strong winds. For all cases,

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R² = = 0.75 0.78 0.77 (b. phase R² R² = 0.77R²(b.= phase) R² = 0.85 (b. phase)

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0.35 R² = R² = 0.95 (b. phase) ice+graupel+snow 2 R² = 0.82 (b. phase) 0 1 0 = 0.82 lightning 0 3 0R²04 08 04 R² 08 12 12 16 16 = 0.35 R² (b. phase) 0.34 08 R²= 12 12 16 16 0= 0.95 000420 04 08 0 R² (b. phase) 2= =0.82 08 0.91 08 (b. 08 phase)08 12 004 04R² 04 12 UTC 16 04 12 16 12 UTC 16 04 08 12 16 0 04 1

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R² = 0.95 (b. ph R² = 0.82 R² = 0.95 (b. phase) R² = 0.63 1 3 R²R²==0.82 0.97 (b. phase) R² =0 0.95 (b. phase) 00

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0.82 = 0.82 R²==0.63 R² R² 0.35 1R² =R² R²=R² =0.97 0.95 (b. phase) R² =0.63 (b. phase) R² (b.0.95 phase) ==0.82 13may2008

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2 R² = 0.75 R² = 20.75 13 Dec 2005 12 2 2 = 0.75 13dec2005 R² =R² 0.77 (b. phase) R² R² = 0.77 (b. =phase) 0.75 = 0.49 R² 0.57 0.69 R²=== R² 0.49 R² 0.69 R² phase) R²==0.77 R²phase) =(b. 0.77 (b. phase) 2 R² R² = 0.55 (b. phase) R² = 0.67 (b. R²==0.76 0.55 (b.phase) phase) R² =(b. 0.76 (b. phase) R² ==0.78 R² 0.77 R² = 0.88 (b. phase) 3 R² = 0.86 (b. phase)

3000 12000 ice+graupel+snow lightning lightning ice+graupel+snow ice+graupel+snow ice+graupel+snow lightninglightning 3000 3000 12000 3000 3000 lightninglightning 1000012000 10000 ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow 2000 lightning lightning 2000 10000 10000 lightning 8000 lightning lightning lightning 2000 8000 2000

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0.69 1 R²R²= =R² 0.64= 0.63 0.82 (b. phase) R²= =0.76 3 R² 0.97 (b. phase) R² = R² 0.80= (b. phase)

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1 = 0.64R² = 0.64 R²R² = 0.82 0.80 (b. phase) R² = 0.80R²(b.= phase) = 0.95 (b. phase) = 0.63 R²0.69 1 R² R² = ==0.82 = R² 0.64 3R²R² (b. phase) R² = 0.760.97 (b. phase) R²R² = 0.80 (b. phase) = 0.95 (b. phase)

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12

12

10001000 12000 12000 1000 ice ice+graupel+snow 23 R² =R²0.69 12000 = (b. 0.63 R² ==0.88 phase) 1 12000 lightning R² 0.88 (b. phase) R² = 0.97 (b. phase) ice+graupel+snow 0.64 = 0.64 = 0.64 10000 = 0.69 R² R² R² 13may2008 ice+graupel+snow lightning ==phase) 0.82 2 R²R²=30.76 12000 ice lightning R²R² ice 12000 ice 10000 10000 lightning 12000 0.97 (b. phase) (b. 10000 06nov2008 =0.35 (b. R² =0.80 (b.phase) phase) R² =0.76 (b. phase) 0.80 (b.0.80 phase) 1 R² 3000 lightning ice+graupel+snow =0.78 R²==R² lightning 2500 ice lightning R² = 0.95 (b. phase) 2500 2500 2 R² 12000 0.77 icelightning ice+graupel+snow lightning R²= =0.64 lightning 10000 0.82 phase) R²R² 0.88 (b. (b. phase) 1 R² 12000 0 === 0 lightning ice ice R² (b. phase) 8000 033 0 10000 =0.86 0.82 lightninglightning 10000 R²R² = 0.80 (b. phase) 10000 lightning 10000 8000 = 0.35 2000 8000 2000 R²04= 0.34 08 08 lightning 04 12 12 16 16 20 20 2500 8000 R²= 0.95 (b. phase) 2000 2 R² R² 0 0 2000 2000 ice 10000 (b. phase) 0 0 2= =0.82 R² 0.91 08 (b. phase) 10000 8000 8000 04 12 16 20 6000 04 08 12 16 20 8000 lightning 8000 8000 20006000 11 1 1 6000 6000 UTC 1500 UTC 1500 1500 8000 22 8000 6000 1 6000 4000 6000 6000 4000 1500 1 1 6000 1000 1000 4000 1000 1 4000 1 600040001000 1000 6000 4000 2000 4000 4000 10002000 4000 11 2000 500 2000 500 500 4000 40002000 0 0 2000 2000 2000 500 0 0 040 0 0 00 2000 2 2 08 12 16 20 0 0 04 08 12 16 20 0 0 00 04 2000 04 08 12 16 20 12 16 20 20000 00 12 16 20 0 08 08 12 UTC 16 20 004 2 0004 UTC 04 12 16 08 12 16 20 000 20 04 04 08 08 08 12 16 20 UTC 12 16 20 UTC UTC 0 04 0 04 08 12 UTC 16 20 04 08 16 08 12 16 20 04 20 2

g/kg g/kg g/kg g/kg g/kg

16

UTC UTC 12 12

N of lighnting N of lighnting

1

12

12

UTC

1

g/kg g/kg g/kg g/kg N of lighnting g/kg g/kgg/kg g/kg g/kg g/kg

1

08

0 0.82 (b. phase) 0 2 R² = 2 0 04 0 04 08 08 1 1 04 08 08 0 2 0 042 04 08 08 1 041

N of lighnting N of lighnting

1000 1000 ice+graupel+snow 12000 ice+graupel+snow 12000 10000 ice lightning lightning lightning ice 1000 100012000 ice ice 12000 10000 lightninglightning ice 10000 10000 10000 10000 10000 10000 10000 1000 ice 10000 1000 10000 lightning lightning lightning lightning ice+graupel+snow ice+graupel+snow lightning 12000 10000 lightning 0 8000 0 10000 lightning lightning ice 10000 10000 8000 8000 8000 8000 8000 8000 8000 16 20 8000 8000 N lighnting N Nofoflightning Nof oflighnting lighnting Nlighnting ofof lightning lighnting NN ofoflightning

g/kg g/kgg/kg

04R² = 0.35 08

04 2 2

6000 4000 6000 4000 4000 4000 4000 4000 4000 3000 2000 4000 2000 4000 26feb2007 26feb2007 1 1 R² = 0.75 ice+graupel+snow 20002000 2000 R² = 0.77 (b. phase) 2000 lightning 2000 002000 20 0 3000 2 3000 2000 ice+graupel+snow ice+graupel+snow 0.49 04 12 16 20 00 0808 12 16 20 R² = 0.49 0 00 R² 0= 04 0 R² =04 0 2000 R² =(b.0.55 (b. 08 phase) 0.55 phase) lightning lightning 12 UTC 16 16 20 0404 08 12 20 0 08 12 16 20 UTC 0 0 0 0 04 08 12 16 20 08 12 16 04 08 12UTC 12UTC 16 04 08 16 20 20 20 UTC UTC 1 UTC UTC UTC 2000 2000

20

20

12000 1000 1000 12000 12000

R² = 0.97 (b. phase)

0

g/kg g/kg g/kg

16

=(b. 0.63 = 0.63 =R² 0.88 (b. phase) R²phase) = 0.91 2R² R² R² 03 R²3===0.82 0.91(b. (b.phase) phase) R² 0.97 (b. phase)

g/kg g/kgg/kg g/kg g/kg g/kg g/kg

4000

16 16

N of lighnting

04

12

UTC 0 04 0 2000for the same period and f UTC 08 both 12parameters 20 given square) between parameters is 08given for the 16same is period and for the time period unt12 04 08 1 04 1 12 06nov200816 20

ice

= 0.35 R² R² = 0.34

N of lightning lighnting of lighnting NNofof lightning N of lightning g/kg g/kg g/kg

10

0 2000 20008000 10000 10000 8000 8000 8000 20 8000 8000 8000 0 0 0 0 0 6000 8000 6000 2020 20 8000 6000 6000 6000 6000 20 20 6000 0 0

N of lighnting

4000 4000

20

UTC

1

2

ice+graupel+snow ice+graupel+snow lightning 2R² R² 3 R²R² ==phase) 0.77 =(b. (b.== phase) 0.88 (b. phase) R² R² 0.95 (b. phase) phase) 2= 0.88 R² 0.95 R² 0.95 (b. phase) lightning =0.88 0.95 (b. phase) 0.86 phase) 3 R² =33R² R²(b. = 0.86 (b. phase) 13may2008 = 0.34 = 0.78 R² R²

lightning

16

1

g/kg g/kg

N of lighnting

1000

1000 12000 12000 6000 6000 12000 12000 12000 12000 12000 ice ice ice ice 1000 ice+graupel+snow 1000 1000 ice lightning lightning lightning 10000 lightning ice 12000 4000 12000 4000 lightning 10000 10000 10000 10000 lightning 10000 10000 1000 0 1000

1

2

08 12 0 304 lightninglightning 04= 0.34 12 R² R² = 0.34 08 0R²2= 0.91 00 UTC phase) R² =(b. 0.91 (b. phase) 004 04 004 08 08 08 1212 12 1616 11 04 1 04 08 12 08 12 16 0 2 2 UTC UTC 04 08 12UTC UTC 16 08 12 16 16feb2007 1 UTC UTC 2

of lighnting N ofNlighnting

06nov2008 06nov2008 13 May 20082008 13may2008 13may2008 13 May 06nov2008

12

2

1

maximum of both lightning occurrence. square) between both parameters is given the same period for the time period until the period a square) between both parameters is period given for thethesame UTC 13may2008 06nov2008 13dec2005 30oct2006 square) between parameters is given for for the same period andand for the time until maximum of lightning occurrence. 06nov2008 30oct2006 13 Dec 2005 13dec2005 30oct2006 613dec2005 Nov 2008 613dec2005 Nov06nov2008 2008 30oct2006 13 30oct2006 Dec 2005 maximum of lightning occurrence. occurrence. 12000 12000 2 21 2 12000 12000 12000 1 613may2008 Nov06nov2008 2008 13may2008 13may2008 1 12000 06nov2008 12000 12000 3000 2 11 1 11of 12000 13 Dec 2005 maximum lightning occurrence. maximum occurrence. 12000 3000 2 R² == 0.82 ice+graupel+snow 0.78 R² ==0.78 = 0.78 13dec2005 0.82 occurrence. 0.82 == 0.78 30oct2006 R²lightning = of 0.63 lightning R² R² R² 0.82 1 ice 1= 0.78 1 R² 3000 3000 ice maximumR²of ice 1 R² 1000 3000 13dec2005 1 = R² 0.77

8000 8000 2000 2000

N of lighnting N of lighnting

1

N of lightning lighnting NNofoflightning

2000 2000

g/kg g/kgg/kg g/kg

2000

N of lightning N of lighnting N of lightning N of lightning of lighnting N ofNlighnting g/kg

1

N of lightning N of lighnting

g/kg

3000 3000 lightning 3000 3000 ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow 3000 12000 12000 lightning 3000 2000 lightning lightning lightning ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow lightning lightning 2000 lightninglightning 10000 10000

3

6000 6000

6000

1 12 22 11

g/kg g/kg g/kg g/kg

0

20

3000

R² (b. 0.82 (b. phase) R² =(b. 0.82 (b. phase) = 0.82 phase) R² = 10.82 ice+graupel+snow ice+graupel+snow 01 phase)

0

0 8000 8000

20 8000 20

10000 2000 10000

N of lighnting

16

20 20

ice+graupel+snow

g/kg g/kg g/kg g/kg

10000 20

20

20

30 Oct 2006

13may2008 13 May 2008 R² = 0.82 0.82 R² = R² = =0.35 0.95 0.63(b. phase) = 0.35 R² = R²R² R² R² = 0.35 R²==30.35 0.95 (b. phase) R² = 0.97 (b. phase)

2 1

g/kg N of lighnting N of lighnting

lightning

4000

0 2000 2000 200002000 2000 2000 2020

16 16 UTC UTC

2 R² = 0.69 R² == 0.76 0.49(b. phase) R² R² = 0.49 R² =(b.0.55 (b. phase) R² = 0.55 phase) R² = 0.77 R² = 0.77 R² (b. = 0.86 (b. phase) phase) 3 R² 3= 0.86

g/kg g/kg g/kg g/kg

N of lighnting N of lighnting

1000

12000 4000 12000

g/kg g/kg g/kg g/kg

N of lighnting

6000

16

2

2

2000

2000

1000 lightning

12 12

12 16 12 16 08 12 16 08 12 16 12 16 12 UTC 16 16 12 UTC UTC UTC UTC UTC UTC 16feb2007

2

2

2

10000 8000

ice

2000 2000 00

20 20

20

13dec2005

08 08

26feb2007 16feb2007 26feb2007 26feb2007 R² = 0.75 16f 3. +Temporal evolution diagrams of (g/kg) andlightning lightning for 6UTC casesto Fig.Fig. 3. 3. Temporal evolution diagrams of ice anddiagrams lightning for 6ice+graupel+snow casesconcerning concerning the time period 04:00 26 Feb 2007 16 3. Temporal evolution offor ice+graupel+snow (g/kg) and for 6 2000 cases 2000 26feb2007 R² = 0.77 (b. phase) 26feb2007 13dec2005 diagrams ofFigure 13dec2005 Temporal evolution ice+Figure +graupel graupel +snow snow (g/kg) (g/kg) and lightning 6Figure cases the time period 04:00 UTC to and lightning R² = 0.75 R² = 0.75 4000 2000 3. Temporal evolution diagrams ice+graupel+snow (g/kg 22(R square) 4. diagrams of of ice (g/kg) for R² = (b. 0.77 (b. phase)evolution R² =Temporal 0.77 phase) 26 cases 22:00 UTC. In the upper left corner the value of R between both parameters is given for the same period and for the time period R² = 0.75 2 Figure 3. Temporal evolution diagrams of ice+graupel+snow (g/kg) and lightning for 3.0In Temporal evolution diagrams of ice+graupel+snow ( R² = evolution diagrams of 22:00 ice+graupel+snow (g/kg) and lightning for 6 cases (R concerning the time period 04:00 UTC to UTC. the upper left corner the value of R = 0.75 0.78 R² 22:00 R²UTC. the upper left corner theFigure value of3. R Temporal (R square) between both parameters isFigure given the same period and for the time period 0 0 0for 0 (R concerning the time period 04:00 UTC to 22:00 UTC. In the upper left corner the value of R = 0.77 (b. In phase) 2000 0 R² = 0.77 (b. phase) 0 0 R² = 0.85 phase) 08 le R² = 0.49 R² = 0.49 04 (b.value concerning theUTC time 22:00left UTC. upper 20 04 04 08 08 12 12 04:00 16 16UTC 20 to untiluntil the maximum of lightning occurrence. period 04:00 toperiod 22:00 UTC. In the upper corner the of1 2 In 04 08 12 16 20 R² (b. = 0.55 (b. phase) 04 08 R² = 0.55 phase) 2R the maximum of lightning occurrence. (R concerning the time period 04:00 UTC to 22:00 UTC. In the upper left corner the value of concerning the time period 04:00 UTC to 22:00 UTC. In the upp square) between both parameters is given for the same period and for the time period until the the time period 04:00 UTC to microphysical 22:00 the upper left corner the R (R 0 In 0value UTC UTC square) between both parameters is given for theUTC. same period and for the time period untilof the 0 UTC 6 D. K. Katsanos etconcerning al.: Relationship between lightning and parameters over the Mediterranean

12000

ice 12000

0808

2

3000

3000 ice+graupel+snow +graupel+snow lightning tning

oflighnting lighnting NNof

11

08 08 08 08

20

20 20 16

16

g/kg

04

lightning

1000

00 00 04 0 04 04 04 04 04 08

00

12000 120004000 12000 4000 12000 ice+graupel+snow 1 ice ice 1000 1000 1 ice+graupel+snow 2 12000 = 0.35 R² lightning 3 R² = 0.35 4000 lightning lightning 1000 10004000 10000 ice lightning 13may2008 2000 3 1000 1000 2000 1000010000 10000 10.82 R² = 10.82 phase) R² R² = (b. (b. phase) = 0.35 R² = 0.34 lightning 0.34 2R² = 0.91 12000 R²==(b. 10000 R² 0.82 (b. phase) phase) 0 0 2000 2000 0 0 ice 8000 R² = 0.91 (b. phase) 0 004R² = 0.35 08000 08 12 16 20 08000 8000 04 08 12 16 20lightning 08 (b. phase) 12 16 20 204 0 04 08 12 16 20 010000 0 0 R² = 0.82 8000 UTC UTC 2 0 0 0 0 0 0040 0 08 08 12 UTC 16 16 206000 04 12 UTC 20 0 0 0 04 04 0 6000 08 12 16 20 04 08 12 16 20 04 08 12 16 20 6000 08 12 16 20 6000 1 1 08 UTC 12 UTC12 16 20 04 1 04 08 16 20 80006000 UTC UTC UTC UTC 4000 UTC 4000 26feb2007 26 Feb UTC 2007 1 4000 4000 1 1 60004000 2000 2 3000 2 3000 2000 16feb2007 16feb2007 ice+graupel+snow ice+graupel+snow R² = 0.49 30oct2006 30oct2006 R² = 0.49 2000 16feb2007 4000 2000 16feb2007 R²2(b. = 0.55 (b. phase) R² = phase) 2000 2 0.55 3000 3000 lightning lightning 0 0 0 2 = 0.75= 0.75 0 3000 3000 R² R² 0422 08 12 16 20ice+graupel+snow 2 3000 3000 04 08 (b. phase) 12 16 ice+graupel+snow 20 0 0 0 R²==(b. 0.77 R² =0.75 0.77 phase) 2000 0 0.75 R² 0 R² = 0 lightning lightning ice+graupel+snow UTC ice+graupel+snow = 0.69 R² R² = 0.69 ice+graupel+snow 04 R² 08 12 UTC 16 16 20 04 08 12 20 ice+graupel+snow R² =(b.0.77 (b. phase) = 0.77 phase) 04 08 12 16 20 2000 2000 R² (b. = 0.76 (b. phase) R² = 0.76 phase) lightning lightning lightninglightning UTC UTC 0 0 UTC 2000 2000 08 12 16 20 104 1 13may2008 2000 2000 2000 2000

4000 4000 4000 40002000

4000

1

g/kg g/kg

0

ice+graupel+snow

04

04

0

20

11

UTC

=R²0.63 = 0.63 ==R² 0.69 = =R² 0.69 R² R²R² 0.69 0.69 3 = R² 3R² =R²(b. 0.97 R² =(b. 0.97 (b. phase) =(b. 0.76 (b. phase) R² phase) = 0.76 (b.phase) phase) R² =0.76 0.76 phase)

1

1000 6000 4000 6000 6000 600060006000

0 0 04 04

0

8000 8000 6000 8000 80008000 8000

1

1

0

20

2000

22

00

20 20

20

R² = 0.91 (b. phase) 1

1

1

3000 3000

2

R² = 0.49 R² 2 = 0.49 0.49 R² =0.49 0.55 (b. phase) R² =R² = 0.55 phase) = (b. 0.77 R² = R² = 0.77 R²phase) R² = R² 0.550.86 (b. = 0.55 (b. phase) 2R² phase) 3 2 2 =3 R² 2 (b. = 0.86 (b. phase)

3000 ice+graupel+snow ice+graupel+snow 12000 12000 12000 lightning 12000 12000 10000 lightning 12000

1

11

1

1

26feb2007 26 Feb 2007

2

g/kg of lightning N ofNlighnting NN of of lighnting lightning oflighnting lightning NNof g/kg g/kg

2000 2000

2000 16 16

0 0

12000 3000 3000 12000 12000 ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow lightning 12000 10000 lightning 12000 12000 lightning lightning lightning lightninglightning 10000 ice 10000 ice+graupel+snow

13 Dec 2005 13may2008

2 R² 0.63 R² ==0.69

R² = 0.35

26feb2007 13dec2005 26 Feb 2007 13dec2005 2

3000 12000

ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow ice+graupel+snow lightning lightning lightning 2000 lightning 10000 lightning 10000 10000 10000 10000 10000 8000

R² = 0.34 R² = 0.34 R²2= 0.91 phase) R² =(b. 0.91 (b. phase)

1 222

16

16 16 12 16 1212 16 12 16 08 UTC 16 UTC12 UTC12 16 08 UTC 12 UTC12 UTC UTC

08 08

08 08

UTC

N of lighnting

4000

2

N of lighnting

0

UTC

N of lighnting

4000 4000

g/kg g/kg

N of lighnting

g/kgN of lighnting

N of lighnting

6000 6000

g/kg g/kg g/kg g/kg

3

g/kg g/kg

10000

6000

0

2000 0 0

16 30oct2006

06nov2008 30oct2006 30oct2006 UTC 30oct2006 06nov2008 13 Dec 2005

0.34 2 R²R²= =0.82 (b. phase) 2

1 1 21 22

oflighnting lighnting NNof

UTC

R² = = 0.63 R²0.69 3 R² = 0.76 (b. phase) R² = 0.69 R² = 0.97 (b. phase) ice+graupel+snow ice+graupel+snow 0.77 R² phase) R² R² = 0.77 = 0.77 =0.76 0.77 R²(b. R²== lightning R² 0.86 phase) R² =3330.86 phase) R²lightning =(b.0.86 (b. phase) R²(b. =3 0.86 (b. phase) 3=

10000 10000

8000

20 20

D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean UTC

30 Oct 2006 13dec2005 13dec2005 13may2008 13 May 2008 13dec2005 13dec2005

2

lighnting NNofoflighnting

g/kg

0 0 00 04 0 08 04 008 08 04 04 0 04 040 004 04 04 04

0

12

= 0.69

g/kg g/kgg/kg g/kg g/kg g/kg N of lighnting g/kg g/kg

UTC

2

ice+graupel+snow 12000

8000 8000

16 20

g/kg

12 12

0

20

N of lightning N of lighnting

08

UTC

08

2

2000 2000 2000

N of lighnting

08

08

2000 4000 4000 2000 20002000 2000

1

30 Oct 2006 06nov2008

12000 12000

htning

16

R² =R²=0.76 = 0.63 0.69 =(b. R² R² 0.69 0.77 phase) R²R² = =0.97 (b. phase) 2 3 R² R² 13may2008 = (b. 30.76 R² = (b. 0.76 (b. R²== 0.76 (b.phase) phase) R² =phase) 0.97 (b.phase) phase) 0.86 3R² =R² 0.78 R² = 0.77ice+graupel+snow 2 R² = 0.88 (b. phase) (b. phase) 33 R² = 0.86lightning

g/kg g/kg g/kg g/kg

6

08

08

04

16

1

1

N lighnting of lighnting NNofoflighnting

0

04

12

4000 4000 4000

oflighnting lightning of lightning N of N lighnting NNof

04

08

6000 6000 4000 40004000 4000 4000

2000

2000 02000

04

0 04 004

0

lightning e+graupel+snow

204000 0 2000 20 00

16

12 16 12 UTC 16 12 16 UTC UTC UTC UTC

g/kg

0

6000

6000

2

1 1 1 1

2000

1

0

11

1

6000 60008000 8000 6000 6000 6000 6000

2

2

N of of lighnting lighnting N of lightning N

4000 2000 4000

2 22 2 g/kg

4000 4000 4000

2 2

2

g/kg g/kg

6000 4000 6000

N lightning of g/kg lighnting N of

N of lighnting

6000

8000 8000 8000

N of lighnting of lighnting N of N lighnting

20

12

2

2

lightning lightning 8000 800010000 10000 8000 8000 8000

of lighnting N ofNlighnting

1

N of lighnting

g/kg

8000 6000 8000 6000

6000

1

1 1

8000

8000

2

12000 12000 1200012000 12000 12000 ice+graupel+snow 12000 12000 ice+graupel+snow ice+graupel+snow ice+graupel+snow lightning ice+graupel+snow ice+graupel+snow 10000 10000 12000 lightninglightning 1000012000 lightning 10000 10000 10000 lightning lightning ice+graupel+snow ice+graupel+snow10000 10000

0.63 R² R² = 0.63 0.34 R² ==(b. R²3= 0.91 phase) 3 R² phase) R² =(b. 0.97 (b. phase) R² == 0.97 0.91 (b. phase)

N of lighnting N of lightning g/kg g/kg

10000 10000 8000 8000

R²2= 0.91 phase) R² =(b. 0.91 (b. phase)

2

0

200

12

08

04

6 Nov06nov2008 2008

10000 10000

2000 16

12 08

0808

0

R² = 0.77 ice+graupel+snow R² = 0.77 =phase) R²R² =0.77 0.77ice+graupel+snow R² lightning 3 = 0.86 (b. = phase) 0.63 = 0.86 0.63 R² phase) 3 R²3 =330.86 R²R² =(b. (b. R² =0.86 (b.phase) lightning 3= 0.97 3 = R² 0.34 R² =(b. 0.97 (b. phase) R² phase)

3

12000 12000 10000 10000

g/kg g/kg g/kg

lightning lightning

ice+graupel+snow ice+graupel+snow

g/kg

Ng/kg of lighnting

2 2

1

2000

2000

R²3 = 0.97 phase) R² = (b. 0.97 (b. phase) lightninglightning

lightninglightning R²3 = 0.34 R² 3= 0.34 R² = 0.34 0.91 phase) R² = 0.91 phase) = (b. 0.34 R² =(b. R²

g/kg g/kgg/kg

N of lighnting

4000

4000

08 08

g/kg

12000 12000 12000 12000 ice+graupel+snow ice+graupel+snow

R² = 0.63 = 0.63 R² ice+graupel+snow ice+graupel+snow

3 3

2

1 1

0

04 0 0 0 04 04 04 04

0

0

3

6000

6000

0

13dec2005 13may2008 13dec2005 13dec2005 13may2008 13dec2005 6 Nov 06nov2008 2008

13may2008 13 May 2008

8000

8000

0

1 0

20

2000

2

D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean

12000

10000

0

20

20

4000

6000 2000 4000 2000 2000

2000

04

06nov2008 06nov2008 13 May 2008 13may2008

10000

20 16

16

2000

8000 4000 4000 6000 4000

D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean

6 12000

16

12 12 16 UTC 12 UTC UTC UTC

08

2000

1

g/kg

1724

08

0 04

2 1

1 1 1

1

N of lighnting N of lighnt

0

4000

g/kg g/kg

2000

04

N

2000

1

040

4000

4000

1

1

N of

1

1

11

1

04 2

2000

1 1

1 1

08

1

1

1000 4000 500 40004000 on diagrams2000 of ice+graupel+snow (g/kg) and lightning for 2000 4000 2000 20006 cases 2 2000 2000 2000 4000 4000

1

1

N of lightning

g/kg

N of lightning

1

12

1

2

2

1

1

R² = 0.35 lightning 0 2000 500 12000 10000 2000 0R² = 0.82 (b. phase) 0 0 0 500 00 ice 04 0 08 12 16 20 00 2000 0 00004 0 000 0 08 12 16 20 08 12 12 16 16 20 R² =040.35 08 040 0404 08 12 16 08 12 UTC 08 12 1616 16 20lightning 202020 0 0 0 04 04 04 08 12 16 20 04 08 12 08 12 20 0 = 00.82 (b. phase) 0 08 12 UTC UTC 16 16 20 10000 R² 004 08000 0 UTC 08 12 16 20 0 04 0 004 08 12 16 20 UTC 2 UTC UTC 0 0 0 0 0 UTC 12 04 04 04 08 0808 12 20 16 16 20 20 UTC12 UTC 16 UTC 0404 0808 16 16 20 2020 20 08 12 12 16 16 04 08 04 12 UTC12 UTC UTC UTC UTC 80006000 1 UTCUTC UTC 16feb2007 26feb2007 26 Feb 16feb2007 26 Feb 2007 2007

2000 2000 500 20000 20002000 002000 00 20 02000 2000 2020 20 20 0 0 0 20 0 0 0

1 1

1 1

13may2008 06nov2008

R² = 0.82

0.35 R² = R² = 0.95 (b. phase)

0 0 In the upper left corner the value of R 0 1 R² 0 = 0.82 (b. phase) (R 04:00 UTC to 22:00 UTC. 00 0 0R²04= 0.82 0 08 0808 12 16 616 2020 Figure Temporal evolution diagrams ice+graupel+snow (g/kg) lightning 6 cases Figure 3.004004 043. Temporal evolution diagrams of of ice+graupel+snow (g/kg) andand lightning for for 6 cases 12 16 04 08 08 0 04 08 12 16 16 20 08 12 16 08 12 04 08 004 08 12 16 16 20 040= 0.95 08 08 004 R² 0004 00404 (b. 6 20 0 08 phase) UTC 0 0 08 UTC 0 04 UTC 04 08 0040404 04 0 0 08 08 UTC 08 1212 12for 20 20 08 08 16 16 time eters period and the period the 20 is given for 0 the 04 0 UTC UTC 16 08 08 04 0 0 same 04 12 period 20 20to0 22:00 04 08time 12 161604:00 20 UTC 04the08 08time 12 16 UTC 04 08 concerning the to0 until 22:00 UTC. In the upper corner value of R (R20004(R concerning period 04:00 UTC. In the upper leftleft corner the the value of R

20

08

04

08

04 1

08

g/kg

20

g/kg

12 16 20 12UTC 16 UTC UTC UTC UTC 16feb2007 UTC UTC UTC 26feb2007

04

N of lighnting

12 08

0

06nov2008

12 12 12

12 12

16 16 16 16 16

12 16 12 12 16 16 12 UTC 16 12 16 12 UTC 16 12 12 UTC 16 12 16

UTC 16 12 12 UTC 16 12 UTC UTC UTC 16 UTC UTC UTC

20

20

8000 6000 6000

g/kg

26feb2007 16feb2007 30 Oct 2006 square) both parameters is of given for same period for time period until the 04:00 UTC 3000 1 between square) between both parameters is given for the the same period and for the the time period until the 30 Oct 2006 16 Feb 16feb2007 16feb2007 26feb2007 13dec2005 30oct2006 1 3000 13dec2005 3000 1 Fig. diagrams ice lightning forand 630oct2006 cases concerning the time period to200722:00 UTC. In 1 4. 2Temporal evolution 3000 6000the upper 3000(g/kg) and 3000 1 1 3000 4000 4000 ice R² = 0.57 3000 1

pha

1

1

1

R² = 0.82 R² = 0.95 (b. phase)

0

0 04 00 04 0 04 0 04 04 04

08

0 04

08 08 08 08 08

08 11 12 12

1

ice ice+graupel+snow 10000 lightning lightning 10000 2000

R² = 0.69 2 R² = 0.76 (b. phase) R² = 0.49 R² = 0.49 R² (b. phase) R² phase) = 0.55 0.77 0.77 R²=(b. R²== 0.55 R² (b. = 0.86 (b. phase) phase) 3 R² 3= 0.86

2

1

2

6000 3000 3000 ice ice ice ice+graupel+snow ice+graupel+snow 3000

R² = 0.57 0.49 R² = 0.49 R² = 0.67 (b. phase) R² 0.57 = 0.55 (b. phase) 0.55 phase) R² =2(b. R² =2 0.67 (b. phase)

R² 1 = R² = 2 2

2 1

3000 30003000

2 R² = 0.57 12 1 R² = 0.67 (b. phase) R² == 0.57 0.49 R² R² == 0.67 R² 0.55(b. (b.phase) phase)

lightning lightning lightning 4000 2000 3000 3000 ice 3000 3000 lightning ice+graupel+snow ice+graupel+snow 2000 2000 2000 2000 0 lightning lightning ice+graupel+snow ice+graupel+snow 2000 2000 20 lightninglightning 2000 2000 2000

lightning lightning

1

ice ice 3000 ice+graupel+snow ice+graupel+snow 3000 3000 lightninglightning 2000 lightning lightning ice+graupel+snow iceice

12

lightning lightning lightning

08

12

16

UTC

20

613dec2005 Nov06nov2008 2008

1 1

0

2000

08

12

16

20

2000 2000

UTC

1

1

30oct2006 13 Dec 2005 maximum occurrence.of lightning occurrence. 13may2008 06nov2008

1000

1000 1000 1000 1000 1000 12000 1000 12000

2000 2000

0

04

1000 1000 10001000

g/kg

104

1 1 21

0

g/kg g/kg

1

16

UTC

g/kg g/kg

1000 1000 1000 4000 6000 600012000 4000 12000 12000 1000 ice ice 1000 500 1000 1000 ice 1000 2000 4000 400010000 lightning lightning 2000 10000 10000 0 lightning 0 0 20 0 0 0 2020 2000 02000 20 0 8000 20 20 8000 8000 20 0 20 0 00 20 00 6000 0 20 20 6000 6000 20 2020

12

N of lighnting

1000

13may2008 13 May 2008

08

N of lighnting N of lightning N of N of lighnting N of lightning lightning N of lighnting N of lightning NNofoflightning lightning N of lighnting N of lighnting N of lightning g/kg g/kg g/kg g/kg g/kg N of lightning

2000 2000

2

04

0

g/kg g/kg g/kg g/kg g/kg

1

= 0.69 = 0.69

0

g/kg g/kg g/kg g/kg g/kgg/kg g/kg g/kg

2

N of lighnting

g/kg g/kg g/kg g/kg g/kg g/kg

1

1

N of lighnting N of lighnting N of lighnting N of lighnting

1000

4000 4000 12000

ice 12000 12000 ice 3000 ice+graupel+snow lightning 3000 icelightning icelightning lightning lightning ice ice+graupel+snow lightning 3000 3000 10000 10000 12000 12000 ice+graupel+snow ice+graupel+snow lightninglightning 2000 2000 lightning lightning ice+graupel+snow ice+graupel+snow 20002000 8000 8000 2000 lightninglightning 10000 10000

R² R² 2000 2000 04 08 until the maximum of lightning occurrence. R² (b. = 0.76 (b. phase) R² = 0.76 phase) period 04:00 UTCuntil to 22:00 UTC. Inperiod the upper left corner the val parameters isperiod given for the same period and forthe the period un1 2000 parameters square) between parameters is given the same period the time until the time is given for the sameisperiod and for the the of lightning 0time 0 2000 square) between bothboth parameters given forfor the same period andand forfor themaximum time period until 2000 2000 UTC 2000 2000 08 both 12parameters 16 20 given 2000 square) between is for the same period and f 1 04 parameters is given for the same period and for the time period unt 1500 1 6000 occurrence. 1 6000 8000parameters 2000 8000parameters 2000 is given for the same period and for the time period until the maximum of lightning is given for the same period and for the time period until the maximum of lightning parameters is given UTC for samecoefficient period andR for occurrence. 1500 1500 1000maximum of lightning occurrence. 2 the time period 1000Furthermore, the correlation 1000 occurrence. the time distribution 06nov2008 of the sum of lightning within boxesoccurrence. of the selected box. maximum of lightning

g/kg g/kg g/kg g/kg g/kg g/kg

6000 6000 1000

g/kg N of lighnting N lighnting of of lighnting N ofNlighnting

N of lighnting

2000 8000 8000

2

R²2= 0.57 R² = 0.67 (b. phase) R² 2= 0.67 (b. phase)

N of lightning N lighnting of lightning N of N N of lighnting of lighnting NNof of lightning N of lighnting Nlightning of lighnting N of lightning g/kg

2 1

g/kg g/kg

12000

g/kg

16feb2007 4000 R² = 0.78 26feb2007 26feb2007 26feb2007 Figure 4. Temporal evolution diagrams of the iceFigure (g/kg)period and lightning 6to cases concerning the time and lightning 16f 16feb2007 16for Feb 2007 Fig. 4.1 Temporal evolution of ice (g/kg) and lightning for 6given cases concerning time 04:00 UTC 22:00 UTC. In upper R² = 0.78 26 Feb 2007 26feb2007 1 3000 Figure 26feb2007 4. Temporal evolution diagrams offor ice (g/kg) fo = 0.85 0.75 (b. 2 (R square) 26feb2007 R²== 16 = 0.78 R² 3. Temporal evolution diagrams of ice+graupel+snow (g/kg) and lightning 6time cases 16feb2007 R² phase) 0.78 R² 16feb2007 16feb2007 13dec2005 30oct2006 13dec2005 30oct2006 3000 = lightning 0.75 left corner the ofoccurrence. Rdiagrams between both parameters is for the same period and for the period until the maximum of = 0.75 0.78 time Figure 3.1 4.Temporal evolution diagrams ice+graupel+snow (g/kg) and lightning for 6the cases maximum maximum of lightning occurrence. R² = R² = 0.78 R² Figure evolution diagrams ofoffor ice (g/kg) and for 6time cases concerning the 3000 3000 R² snow = (b. 0.85 (b. phase) 3000 11 Temporal =of 0.77lightning (b. value phase) evolution = 0.78 =R²= 0.64 R²R² Temporal diagrams of ice + graupel + (g/kg) and lightning 6 cases concerning the period 04:00 UTC to andR²lightning 4000 R² = 0.85 phase) 0.88 (b. phase) 2 1 Fig. 3. 3000 2000 ice R² = 0.77 (b. phase) R² = 0.88 (b. phase) 2 R² = 0.77 (b. phase) 3000 1 0.78 R²= =0.57 R² = 0.85 (b. phase) R² = 0.64 R² Figure 3. Temporal evolution diagrams of ice+graupel+snow (g/kg 0.64 4. Temporal evolution diagrams of ice (g/kg) for R² = Temporal R² = 0.80 value (b. phase) ice between R² = 0.85 (b. phase) left lightning corner the of R (R square) both parameters is given for the same period and for the time period until the maximum of ice Figure 4. evolution diagrams of ice (g/kg) and lightning for 6 cases concerning the time Figure 4. Temporal evolution diagrams of ice (g/kg) and lightning for 6 cases concerning the time = 0.78 R² (R square) between both period 04:00 UTC to 22:00 UTC. In the upper left corner the value of R ice 2 = 0.78 R² = 0.75 ice Figure 4. Temporal evolution diagrams of ice (g/kg) lightnin R² =and 2500 R² = 0.57R²R²= = 2 R² =(b.0.80 (b. phase) lightning 0.78 R² 2 and 0.67 (b. phase) ice occurrence. 2 period 04:00 UTC to 22:00 UTC. In the upper left corner the value o 0.85 (b.In phase) R²R² ==0.80 phase) (R concerning the time period 04:00 UTC to 22:00 UTC. In the upper left corner the value of R 0.78 R² = 0.75 = 0.75 2500 ice 22:00 UTC. the upper left corner the value of R (R square) between both parameters is given for the same period for the time period R² lightning 0.85 (b.upper phase) of R² = 0.77 (b. phase) 2500 left (R square) between both(R 0 R² period 04:00 UTC to 22:00 UTC.UTC In the upper corner value R² = 0.67 (b. phase) concerning the0.77 04:00 to lightning 22:00 UTC. InR²0 =the leftR corner the value R²time = 0.85 (b.period phase) lightning lightning 2000 0of R = 0.85 (b. phase) lightning R² =(b. 0.77 (b. phase) (b. phase) R²R²==0.85 phase) lightning occurrence. 2 lightning theUTC time 04:00 UTC tobetween 22:00 UTC. In the value upper of le period 04:00 toperiod 22:00 UTC. Insquare) the upper left corner 2000period (R between both 04:00 to for 22:00 UTC. the upper corner the R(R parameters isUTC given the same period andconcerning forleft the time until maximum of lightning 04 theperiod 08 value 16 20 square) both period 04:00 UTC to 22:00 UTC. In In the upper left corner value of12 of R2the

lightning lightning

2000

08

N of lighnting

3000 12000 3000

ice ice+graupel+snow icelightning 3000

08 04

04

UTC 16

20 00

g/kg

04

ence.

0

0 00 0

8000 8000 2000 6000 1500 1000 10001000 1000 6000 6000 1000 1000 1500 1000 4000 1000 1000 1000 1000 1000 1000 12000 12000 4000 4000 ice 1000 2000 500 lightning ice 0 10000 12000 2000 0 00010000 500 202000 0 lightning 0 20 20 0 20 20 20 00 0 ice 20 00 0 20 10000 8000 20 16 20 2008000 0 20 20 20 lightning 0 20

lighnting Nlightning of lightning NNof lightning Nofof N of lighnting N of lightning N of lightning

2000

08

R² = 0.85 phase) = 0.78 R² (b.

0.75 R²== R² =0.64 0.78R² = 0.85 (b. R² R²==0.80 phase) R² (b.(b. phase) R² = 0.77 0.85 (b. phase) R² = 0.69 R² = 0.64 R² = 0.76 (b. phase) R² = 0.80 (b. phase)

g/kg

0

104 2

N of lightning

02

1

2 1

N of lightning g/kg g/kg g/kg g/kg g/kg g/kg

4000 4000

2 1

121

lightning 3000 ice lightning ice+graupel+snow lightning 20002500 2000 20002000 lightninglightning ice 10000 10000 2000 2000 2000 2000 2000 2000 8000 2500 lightning 2000 2000 2000

g/kg

1

g/kg

g/kg

1500 1000 4000 6000 6000 4000 40004000 1000 6000 6000

6000

UTC

2000

01500 0 6000 8000 8000 6000 6000 6000 8000 20 8000 6000 60006000

3000 3000 ice lightning icelightning ice ice 3000 ice ice+graupel+snow lightning lightning ice+graupel+snow ice+graupel+snow ice 12000 lightning 12000 lightning lightning lightning ice 10000 lightning lightning lightning

NN of of lighnting N of lightning lighnting lightning NNofoflighnting

20

13dec2005

oflightning lighnting NN ofof lighnting N lightning of lightning N of lightning NNlighnting of of NN Nlightning of lighnting Nofof lighnting

UTC

16

16

R² 0.85 (b.phase) phase) 30oct2006 == 0.78 1 =R² R² =phase) 0.78 R² = 0.78 R² ==(b. 0.77 (b. R² 0.77 0.69 R²R² =R² R² = 0.78 0.67 (b. phase) = 0.69 ===0.57 R² 0.49 R²=R² 0.88 (b.phase) R² = 0.64 R² R² =phase) 0.85 (b. phase) R² 0.76 R² 0.85 (b. phase) =R²=0.85 (b. phase) =(b. 0.76 (b. phase) R²R² = 0.67 (b. R² 0.55 (b.phase) phase) =R² 0.78 R² = 0.80 (b. phase) R² = 0.77 R² = 0.88 (b. phase) 0.86 (b. phase) 3 R²R²= =0.64 R² = 0.80 (b. phase)

1

N of lighnting

12

2

N of lighnting

8000

12

12

N of lighnting

08

ice

lightning lightning 2500 2000 lightning 2500 lightning ice+graupel+snow ice+graupel+snow lightning lightning lightning 2000 2000 10000 10000 10000 2000 80002000 2000 2000 8000 8000 8000 8000 lightninglightning 2000 2000 0 0 8000 2000 8000 8000 1500 1500 2000 2000 12 16 20 6000 12 16 20 6000 6000 6000 6000 1500 1000 1500 6000 6000 1000 1000 6000 1000 4000 1000 4000 1000 13may2008 4000 4000 4000 1000 1000 1000 12000 4000 1000 4000 500 4000 1000 500 1000 ice 2000 2000 13may2008 2000 20002000

N of lighnting N of lighnting

08

ice

3000 ice+graupel+snow iceice lightning lightning ice+graupel+snow 1000 ice ice 10003000 12000 lightning 12000 12000 ice lightninglightning lightning icelightning lightning 2500 10000 lightning 3000 3000 ice 2500 10000 10000 lightning 10000 10000 ice ice ice+graupel+snow ice+graupel+snow

lighnting NN ofof lighnting N of lighnting g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kgg/kg Ng/kg of lighnting g/kg g/kg g/kg g/kg g/kg g/kg g/kg

1 1 1 04 2 2

g/kg

1

04

13dec2005 = 0.82 0.82 == 0.78 = 0.64 R² == (b. 0.57 R² R² 0.77 R² 1R² R²== 0.55 0.55 (b. phase) 0.64 R² phase) R²R² =phase) 0.77 R²= R² 0.67 phase) 1 R²= =0.67 R² R² == (b. phase) R² ==(b. (b. phase) R²0.88 =(b. 0.80 (b. phase) 0.86 (b. phase) 2 = 0.95 (b. phase) 0.95 (b. phase) R²R² = 0.67 0.80 (b. phase) =R² 0.64 R² =R² 0.86 (b. phase) 3= 2R² =2 0.78 R² 0.64 R²==0.63 0.80 phase) =(b. 0.63 R² R² R² R² = 0.80 (b. phase) = 0.88 (b. phase) = 0.69 3 R² = 3 =R²0.97 R²0.69 phase) R² =(b. 0.97 (b. phase) R² (b. = 0.76 (b. phase) R² = 0.76 phase)

3

NNofoflightning Nlighnting oflightning lighnting of lighnting N NN of lightning lightning N of lightning lighnting g/kg Nof of NN ofof lighnting g/kg g/kg

4000 4000 4000 4000

10

11 2 2

12

R² = 0.34 R² = 0.34 R²2= 0.91 phase) R² =(b. 0.91 (b. phase) 0

N of lighnting lighnting N ofNlighnting NN ofof lighnting of lighnting

4000

6000 6000 6000 6000

3 304 lightninglightning 08 R² (b. = 0.86 (b. phase) phase) 3 R² 3= 0.86

g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kg

6000

8000 8000 8000

g/kg g/kg g/kg g/kgg/kg g/kg

8000

ice+graupel+snow ice+graupel+snow

0

g/kg N ofNlighnting of lighnting oflighnting lighnting NNof

20

N of lighnting

16

3000 ice ice+graupel+snow ice ice lightning lightning 1000 1000 10000 icelightning ice+graupel+snow 10000 2500 1200010000 12000 lightning lightning lightning 10000 10000 0 8000 2000 16 20 10000 80008000 10000 8000 2000 lightninglightning 10000 100008000 8000 8000 ice

R²0.76 = 0.97 (b. phase) 10000 lightning R² = (b. phase) R² = 0.88R² (b.=phase) ice 12000 12000 10000 lightning R² 0.82 (b. phase) 0.82 (b. phase) lightning maximum of lightning occurrence. R² = lightning 0.80 (b.= phase) lightning maximum of occurrence. 10000 2500 lightning ice+graupel+snow ice+graupel+snow R² = 0.77 R² = 0.77

10000 10000 10000 10000 0 8000

lighnting NN ofoflighnting N of N lighnting Nof oflighnting lighnting

lightning

lightning lightning

Nlightning ofof lightning of NNof of lighnting Nlightning NN ofof lighnting Nlighnting lightning lighnting NNofoflightning

0.78 R² 1 R² R² = 0.88 (b. = phase) 0.63 = =0.80 (b. phase) R² =0.69 0.95 (b. phase) R² = 0.78R² =R²0.35 R² = 0.35 R² (b. 0.88 phase) 3 R²R²= =0.64

ice ice+graupel+snow 10000

g/kg

g/kg

1000

g/kg

g/kg

N of lighnting

2000

g/kg g/kg g/kg g/kg

lightning

g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kg g/kg

3000

ice+graupel+snow

g/kg

1 1 1 60004000 on diagrams2000of ice+graupel+snow (g/kg) and lightning for 6 cases 2000 4000 4000 4000 2000 2000 2000 2000 2000 Figure 3. 1 Temporal evolution diagrams of ice+graupel+snow(g/kg) (g/kg)andandlightning lightningforfor6 6cases cases 1 2000 2000 16feb2007diagrams 16feb2007 Figure 3. 1 Temporal offor ice+graupel+snow 2000 2000 2000 2000 2 graupel Fig. 3. Temporal evolution diagrams of ice + + snow evolution (g/kg) and lightning 62000 cases 4. concerning time period 04:00 UTC to 4000 04:00 UTC to Figure 3. Temporal Temporalthe evolution diagrams (g/kg 0(R2 0 2000 2000 evolution diagrams of of iceice+graupel+snow (g/kg) and lightning for 2 3000 3000 2000 2000 0 22:00 UTC. In the upper left corner the value of R 0 for Figure 3. Temporal evolution diagrams of ice+graupel+snow (g/kg) and lightning 6 cases Figure 3. Temporal evolution diagrams of ice+graupel+snow (g/kg) and lightning 0 ice+graupel+snow 0 08 06 cases 0 042 0000 0 for 0 0 diagrams of (g/kg) and lightning for 6 cases 12 16 20 0 concerning the period 04:00 UTC to 22:00 UTC. In the upper left corner the value of R 16 20 = 0.75 0.75 22:00 UTC. In the upper left corner the value of0 R (R between both parameters is given for the same period and for the time period R² R²0 =square) 0 UTC. 04 08time 12 16 ice+graupel+snow 20to 22:00 ice+graupel+snow (R(R0 040 0 concerning the time period 04:00 UTC In the upper left corner the value of R 6 20 0 04 00 04 08 12 16 20 0 0 0 04 12 12 16 16 20 20 04R² =04 08 12 16 20 08 12 16 20 R² =(b. 0.77 (b.08 phase) 0.77 phase) 2000 08 UTC 0 0 04 08 12 16 20 eters is given for the period and for the time period until the0040400 In 008the timetoperiod 22:00left UTC. In 04the value upper le1 0 concerning lightning 0 UTC 16 and 0 00 04:00 UTC 22:00 04:00 UTC. UTC In thetoupper corner 20 16lightning 20 08 of 04 12 UTC 20lightning 12 16 20 Figure 3. Temporal evolution diagrams of ice+graupel+snow (g/kg) lightning for 6R 2UTC. Figure 3. same Temporal evolution diagrams ice+graupel+snow (g/kg) and foroffor 6period UTC 08 UTC until the maximum of lightning occurrence. UTC corner (R the concerning the time period 04:00 UTC toof 22:00 In 080808the upper left the value of2cases (Rcases concerning the time period 04:00 UTC toof22:00 upper left corner the value R 04 1 08 20 04 08 04 08 20 0808 12 04 04 12 12UTC12 16 16 20 20 (RUTC. UTC to 22:00 UTC. corner the value R square) between both is given same period for thetime period untilthethe0 04040 0404 UTC UTClightning 0 0 UTC UTC parameters UTC 6 In the upper left D. K. Katsanos et al.: Relationship between and microphysical parameters over thetime Mediterranean square) between both parameters is16 given for thethe same period andand the period until 08 12 08 12for 20 UTC 004 0 0 0 UTCUTC 16 UTC UTCUTC UTC UTC 04 period 08 12f 2000 2000 2 between 08 both 12parameters 16 2020 given 2 ence. square) is for the same and parameters is given for the same period and for the time period unt 0404 08 12 16 04 08 12 16 20 UTC 30 Oct04:00 2006UTC (R concerning the time period UTC to 22:00 UTC. In the upper left corner the value of R (R concerning the time period 04:00 to 22:00 UTC. In the upper left corner the value of R square) between both parameters is given for the same period and for the time period until the 26Feb Feb 2007 26feb2007 square) between both parameters is given for the same period and for the time period until the 26 2007 16feb2007 26feb2007 06nov2008 13dec2005 30oct2006 13dec2005 30oct2006 of lightning occurrence. 30the Oct 2006 1 is given for the same period and 13dec2005 for time period 1000 untilmaximum the 1of lightning 16 Feb 2007 UTC 16feb2007 30oct2006 UTC UTC 13dec2005 30oct2006 06nov2008 12000 maximum occurrence. 26 Feb30oct2006 2007 26feb2007 26feb2007 30 Oct 20062008 3000 16feb2007 16 Dec Feb 2007 13dec2005 13may2008 13 May 1 613dec2005 Nov06nov2008 2008 1 3000 3000 2 26feb2007 30oct2006 1 1 13 2005 1 21 12000 12000 26feb2007 13dec2005 Feb 2007 30oct2006 occurrence. 2 of lightning 16 2 30003000 occurrence. 11 3000 ice 2 3000 3000 maximum R² = 0.57 16f 26 Feb 2007 1 2same 3000 3000 until ice 12000 3000 =10.57 12000 12000 12000 0.78 13may2008 13 May 2008is given 6 Novfor 2008 06nov2008 12000 R² =lightning 16 12000 3000 3000 22 R² 12000 1 = 0.49 period 12000 3000 22=1 0.78 3000 3000 2 2111 2R² square) between both parameters is icegiven for and the time period the ice 0.78 maximum lightning occurrence. maximum of occurrence. R² 12000 12000 12000 ice 12000 13 Dec 2005 square) between both parameters for the 1the same theice+graupel+snow time period until the 1 1=210.49 3000 3000 ice ice+graupel+snow =of 0.82 ice 3000 3000 R² 1= 0.78 12000 == 0.64 R²period = 0.67 (b. phase)and for R² == 0.75 R² 13dec2005 30oct2006 13dec2005 30oct2006 R² 12000 = 0.67 0.75 12000 R²R² 2 12000 R²0.57 lightning R² 0.57 R² = (b. phase) 0.88 (b. phase) ice+graupel+snow R² = 1 ice+graupel+snow R² = 0.57 = ice lightning

1

3000

1

16feb2007

20

4000

4000 40003000 3000 30003000 2000 iceice ice ice+graupel+snow lightning 2000 2000 lightning lightning lightning 3000 0 3000 ice+graupel+snow ice+graupel+snow 16 20 0 0 2000 2000 lightning lightning 2000 2000 16 20 20

1 12 R² = 0.57 26feb2007 26feb2007 R² = 0.57R² = 0.75 R² ==0.67 (b. (b. phase) R² 0.85 phase) R²(b. =phase) 0.77 (b. phase) 2 R² = 0.67

1

1

1

1

6000 40004000 4000 3000 60004000 3000 4000 ice 2000 20002000 ice lightning 4000 lightning 2000 3000 3000 2000 00 0 ice+graupel+snow ice+graupel+snow 16 2020000 2000 20 20 lightning lightning 2000 2 0 20 20 0 2000 2000 20

UTC

UTC

16 16

16 16 16

6000 6000 1500

4000 1000 6000 4000 4000

R² = 0.64 R² = 0.80 (b. phase)

0

04 00 04 04

08

08 08

11

g/kg g/kg

UTC

12 12 12 UTC

1616

N of lighnting

3000

UTC

12 12

12 12

N of lighnting

16 UTC UTC UTC

10000 3000 2500 lightning 10000 12000 10000 0 0 ice lightning 00 2020 0 20 8000 20 02500 icelightning 2000 0 20 10000 8000 8000 20 20 lightning 2000 6000 1500 8000

N ofNlighnting ofNlighnting of lightning

12

UTC

4000

ice

08

11

12000

ice

lightning ice

N of lighnting

04

12000 1000 1000 1000 12000 3000

ice ice lightning

g/kg g/kg

0

N of lighnting

6000

2

g/kgg/kgg/kg g/kg

0

N of lighnting N Nlighnting ofoflightning

20 20

20

12000

N of lighnting N of lighnting

6 16

g/kg

20

N of lighnting

16

R² =(b. 0.82 (b. phase) 1 R²01= 0.82 phase) 00 08 12 16 00 04 0 08 12 16 08 12 16 0 0404 0 04 04 08 12 16 08 12 16 04 08 12 16 04 08 12 UTC 16 16 004 08 12 UTC UTC 00 004 0 0 08 12 16 UTC UTC 04 04 08 12 16 08 12 12 08 12 16 08 08 12 16 16 16 10404 1 04

g/kg

0

00 8000

13may2008

1

1 = 0.78 ice 2 R² 2 R² = 0.78 12000 1000 1000 1000 1 R² = 0.88 (b. phase) 1000 R² =R²0.88 (b. phase) 2 500 ice ice12000 1000 = 0.64 lightning ice 13may2008 500 1000 10000 = =0.35 = 0.35 10000 0.78 R² R² R² =R² 0.80 (b. phase) 1 ice lightning 10000 0 0 lightning lightning 2 0 R² =R² 12000 10000 0.88 (b. phase) R² = 0.82 (b. phase) = 0.82 (b. phase) 1 0 0 0 0 = 0.64 0 0 R² lightning 0 0 0 10000 08 12 16 ice 20 0 0 04 0 0 04 0 04 08 12 16 20 04 08 04 08 12 16 20 R² = 0.80 (b. phase) 08 12 16 20 80008000 004 04 08 08 0 8000 R² = 0.35 04 0 08 20 08 12 12 16 20 04R² =040.82 (b. phase) 08 12 UTC 16 16 lightning20 10000 00 04 08 UTC 04 08 12 16 20 8000 0 0 0 UTC 000 0 04 08 UTC 04 08 0 0 0 8000 UTC 0 04 04 0 UTC 1212 04 08 16 16 20 20 6000 08 12 16 20 6000 1 04 0808 12 16 20 6000 04 08 12 16 20 1 04 08 12 16 208000 1 6000 1 UTC UTC g/kg g/kg g/kg g/kg g/kg

R² = 0.35 R² = 0.35

0

20

1

2

lighnting NNofof lightning

2000 2000 10000

lightning

16

2

g/kg g/kg

1000

N of lighnting

◦ (thatofinclude occurrence. the almost time distribution the sumtheofarea lightning within boxes of13dec2005 was eventcalculated (04:00 tooccurrence. 22:00 As from the analysis of each the pre0.82 5R²◦=×5 ofoccurrence. maximum lightning for the UTC). entire studied time interval of = 0.82 0.82 30oct2006 R² = R² R² = ◦ 0.95 (b. phase) ◦ ×5 0.82 = 0.95 (b. phase) R² = R² 0.95 (b. phase) R² = 0.82 06nov2008 almost 5 (that include the area of maximum lightning vious two cases, it was evident that the temporal evolution activity) is compared to the average integrated mixing ratio event (04:00 to 22:00 UTC). As from analysis of the pre- of R²R² == 0.95 (b. phase) R² = 0.95 (b. phase) = 0.82 solid activity) isgraupel compared to the average integrated mixing ratio the lightning activity hydrometeor concentrations of ice + + snow of all model grid points that lie within vious two cases, it was R²R²with evident that the temporal evolution of = 0.95 (b. phase) of ice + graupel + snow of all model grid points that lie within was better correlated during the development phase of each 2 16feb2007 the selected box. Furthermore, the correlation coefficient R event. The correlation coefficient R 2 has been also calculated 26feb2007 16feb2007 26feb2007 16feb2007 non diagrams of ice (g/kg) and lightning for 6 cases concerning the time Fig. 4. Temporal evolution of for icetime (g/kg) and and lightning for 6for cases concerning the time 04:00 UTC to 22:00 UTC. In the upper diagrams of ice+graupel+snow (g/kg) anddiagrams lightning 6(g/kg) cases was calculated the entire studied interval of each theconcerning period up toperiod the maximum the observed lightning. Figure 4.R² =Temporal evolution diagrams ice (g/kg) lightning 6 for cases the time 0.78 for Nat. Earth Syst. Sci., 9, 1–8, www.nat-hazards-earth-syst-sci.net/9/1/2009/ Figure 4. lightning Temporal evolution diagrams of of ice (g/kg) lightning forof6and cases concerning time and lightning fo Figure 4.Hazards Temporal evolution of of ice2009 and for 6 cases concerning the time Figure 3. Temporal evolution diagrams ice+graupel+snow (g/kg) lightning 6(g/kg) cases R² = 0.78 Figure 4.and Temporal evolution diagrams offor icethe 2 diagrams ice

lightning

10000 10000

lightning1000 1000 ice lightning 10000 lightning 10000 lightning 2500 10000 lightning

2

g/kg

08

12

16

UTC

== 0.57 R² = 0.64 R² 0.64 R² R² ==0.88 (b.0.95 phase) = (b. phase) R²0.80 0.95 (b. phase) R² (b. phase) R²R² =(b.0.80 (b. phase) R² == 0.67 phase)

N of lightning N of lightning N of lightning

R² = 0.88 (b. phase) occurrence. R² = 0.35 0.95 (b. phase) = 0.80 (b. phase) = R² occurrence. R² =R²0.35

04

N of lightning

1

0

g/kg

2000 2000

g/kg

g/kg g/kg g/kg

g/kg

1

g/kg

1000

g/kg

2000

16feb2007 16feb2007

g/kg

2

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N of lightning N of lighnting N of lighnting N of lightning

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oflighnting lighnting NNof

lightning

lightning

N of lighnting N of lighnting

0.78 3. 4.Temporal evolution diagrams ice+graupel+snow (g/kg) and lightning for 6500 time cases R² =+ 2000 left corner the value valueevolution of R (Rdiagrams square) between between both parameters is given for the same period and the time period until the04:00 maximum of Fig. 3. Temporal ofFigure iceFigure +2both graupel (g/kg) and lightning 6(g/kg) cases concerning the period UTC to and lightning Temporal evolution ofoffor ice and lightning for 6time cases concerning the 4000 R² snow = 0.85 (b. phase) 2000 2diagrams (R square) UTC. In theice upper left corner the R corner R² Figure 3.for Temporal evolution diagrams of (g/kg 4. Temporal evolution diagrams of iceice+graupel+snow (g/kg) for 2 = 0.85 (b. phase) 2000 2 R (R square) between (R 04:00 UTC to 22:00 UTC. InUTC the upper of R agrams of (g/kg) and lightning 6left cases concerning the time 2 both period UTC toof 22:00 UTC. Invalue the left the value of 004:00 22 0corner 500 (R square) between period 04:00 UTC to(g/kg) UTC. Inconcerning the upper corner the value of R2and 2Rboth Figure 3. Temporal evolution diagrams of ice+graupel+snow and lightning for 6left cases (R square) between both period 04:00 tofor 22:00 UTC. Inthe the upper left corner the value of22:00 Rand Figure 3. Temporal evolution diagrams ofupper ice+graupel+snow (g/kg) lightning for 6isperiod cases 0 = 0.49 = 0.49 0=square) concerning the time period 04:00 UTC to 22:00 UTC. In the upper left corner the value of R² R²UTC. =lightning 0.75 0.75 2corner lightning 22:00 In the upper left corner the value of R between both parameters given for the same period for the time R² R² 04:00 UTC to 22:00 UTC. In the upper left corner the value o 0 0period 0 (R 4. Temporal evolution diagrams of ice (g/kg) and for 6 cases the time 2000Figure (R(R concerning the time period 04:00 UTC to 22:00 UTC. In the upper left the value of R 0 04 occurrence. 08 12 0 0 0 2000 0 (R square) between both periodand 04:00 tofor 22:00 UTC. In the upperthe left time corner of R 6 20 R² =(b.0.55 (b. phase) R² = 0.55 phase) 0 the value 0 0 R²UTC =(b. 0.77 (b.08 phase) =04 0.77 phase) 12 cases Figure 4. Temporal evolution diagrams of ice (g/kg) 6 concerning 04R²lightning 08 12 16 04 08 12 16 20 04 08 12 16 2 ame period and for the time period until the maximum of lightning 0 concerning the time period 04:00 UTC to 22:00 UTC. In the upper le 04 08 12 04 08 0 04 08 12 16 period UTC to 22:00 UTC. In 20the upper left corner value of 04same period 08 12 16 is upper given Nat. for the and for the04:00 time period until the 2 0004:00 0 UTCthe 04 08 12 16 20 0the time period until the maximum of lightning parameters is given for same period and for 04 08 2 time (R square) between both .eters In the left corner value of R until the the maximum of lightning occurrence. parameters given for the same period and for period until of lightning 04 08 12 UTC 04 time 08 12 16 maximum 20 period 216 Hazards Earth Syst. Sci., 9, 1719–1726, 2009 www.nat-hazards-earth-syst-sci.net/9/1719/2009/ UTCthe UTC corner (R concerning the time period tosquare) 22:00 UTC. Inis the upper left the value of R (Rthe concerning the time period to and 22:00 UTC. In the upper left corner value of R parameters is given the same period for the time period until the maximum of lightning 2the UTC square) between both is given for the same period and the time until the UTC04:00 UTCfor parameters isperiod given for the same period and forthe period un1 UTC 04 08 12 16 time 20 04 08 12 parameters 16 0both 0 between both parameters isthe given for the same period and for themaximum period until (R square) between period 04:00 UTC tofor 22:00 UTC.UTC InUTC the upper left corner the value of R 2 same parameters is given for the period and for the time until of lightning UTC 1 UTC UTCthe 08 both 12parameters 20 given both04between period 04:00 UTC to 22:00 UTC. In the upper left corner the value ofUTC R (R square) between square) forfor thethe same UTC parameters is given for the 16same is period and timeperiod periodand untf occurrence. eence. period and for the time period until the maximum of for lightning occurrence. 30 Oct 2006 square) between both parameters is given for same period and for time period until 26 Feb 2007the square) between both parameters isperiod given the same period and for the time period until the the maximum of lightning occurrence. UTC occurrence. 16feb2007 1000 26feb2007 1000 occurrence. 2 2 2 13dec2005 30oct2006 06nov2008 1 13dec2005 maximum of lightning occurrence. 30oct2006 1000 isdistribution given for the same and forthe the time period until the maximum of lightning 1000 1000 occurrence. 12000 parameters the time of of lightning within boxes of the selected box. Furthermore, the correlation coefficient R 13may2008 13 Maythe 2008 sum 613dec2005 Nov06nov2008 2008 30oct2006 1 11 3000 13 Dec 2005 1000 1000 3000 1 maximum of lightning occurrence. 1 3000 2 12000 occurrence. 26feb2007 parameters for the time period until the maximum of lightning 1 12000 2 is1 1 given for the same period and 12000 16 Feb 2007 12000 3000 ice = 0.57 21 R² 2 R² 12000 2 ice = 0.78 2 ◦ ◦ R² = 0.57 =of 0.82 ice R² 11 3000 12000 ice 12000 12000 12000 ice maximum lightning occurrence. maximum of lightning occurrence. R² = 0.78 R² = 0.78 ice 12000 1 3000 1 3000 ice = 0.78 3000 1 R² = 0.64 R² = 0.67 (b. phase) R² lightning almost 5R² = 0.88 ×5 (that include the area of maximum lightning for theR²1R² =entire time interval of3000each 13dec2005 was calculated = 0.82 0.82 30oct2006 ice ice R² R² ==0.78 R² 0.67 0.78 (b. phase) studied (b. phase) icelightning ice ice+graupel+snow

ice ice 1000 1000 lightning iceice ice12000 10000

1000

R² = 0.85 (b. phase)

=0.88 R²=R² R² (b. phase) =0.78 0.64

icelightninglightning ice lightning ice

1

R² = 0.85 (b. phase)

R² = 0.64

D. K. Katsanos et al.: Relationship between lightning and microphysical parameters over the Mediterranean Figure 3 shows that: 1. There is a good correlation in general between the temporal evolution of the lightning activity with that of the solid (ice+graupel+snow) hydrometeor concentrations. R 2 varies from 0.34 to 0.77 when the entire time period is considered. 2. The correlation is much better during the development stage of each event with R 2 varying from 0.55 to 0.91. 3. During the decaying phase the lightning activity seems to decrease more rapidly than the concentrations of the solid hydrometeors. Although the correlation coefficient of the number of lightning with the solid hydrometeor concentration is good for each studied case, it does not seem that a general relation between the number of lightning and the solid hydrometeor concentration could be derived. At this point it is interesting to investigate the correlation of each solid hydrometeor species with the lightning. The analysis showed that the best correlation is found with the concentration of the simulated ice. Indeed, Fig. 4 shows the same analysis as Fig. 3 but for ice only. The correlation coefficient between the temporal evolution of the lightning activity with that of the ice concentration, is better than that when all solid hydrometeors are included, and varies from 0.35 to 0.82 when the entire time period is considered. When the time interval is restricted to the development stage, the calculated R 2 varies from 0.67 to 0.95. In recent studies, Mansell et al. (2005) and Barthe and Pinty (2007) using cloud resolving models, in order to study the electrical structure of idealized convective clouds through different parameterizations, concluded that inductive mechanisms of charge separation play a secondary yet important role. Hence, collisions between graupel – droplets, for example, are crucial for the separation of electric charges; the high mixing ratios of graupel at the lower levels of convective regions result to the necessary for lightning production charge separation. This is in good agreement with our Figs. 1d and 2d that show that graupel is the dominant hydrometeor at the lower levels of lightning producing clouds, although there are significant differences between a numerical weather prediction model and cloud resolving models. Barthe and Pinty (2007), suggested also that supercooled water is the key element for the production of graupel, while the presence of other types of hydrometeors, like ice crystals, is also important.

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scarcity of direct measurements of microphysical parameters such as ice content of lightning producing clouds, in the region of the Mediterranean, supports the need for the use of spaceborne passive microwave observations for such type of studies. As spaceborne microwave observations, available from low orbiting platforms cannot provide a continuous monitoring of lightning producing systems, but they only provide snapshots of these events (1–2 per day), another possibility is to relate lightning activity with the simulated microphysical parameters provided by weather forecasting models. For that reason, the present study investigates the possibility of using numerical weather model outputs as proxy for lightning occurrence. Indeed, a number of cases accompanied with strong lightning activity in the central and eastern Mediterranean have been selected. These cases were simulated with the non-hydrostatic MM5 model and the temporal evolution of the lightning activity, observed by ZEUS lightning detection network, has been studied, in relation with the temporal evolution of the simulated convective precipitation, as well as with the concentration of solid (ice + graupel + snow) hydrometeors. The results do not show a clear relationship between convective precipitation and lightning, as convective precipitation is simulated both before and after the whole period of lightning activity occurrence and also in areas without recorded lightning flashes. On the other hand, a good correlation was found between the temporal evolution of the number of lightning with the profiles of mixing ratio of solid hydrometeors and an approximate temporal coincidence in their maximum. The correlation is increased during the development stage of the events and also the correlation increases when only ice hydrometeors are considered in the comparison. These results could be expected, as the presence of ice particles is directly related with the phenomenon of lightning, while on the other hand rainfall, even convective, can still be observed in the absence of lightning activity. In order to quantify their qualitative results, the authors are convinced that it is worth to extend this study to a larger number of cases. Further, other techniques could be considered, such as the Lightning Potential Index (LPI) introduced recently by Yair et al. (2009), that measures of the potential for charge generation and separation that leads to lightning flashes in convective thunderstorms. Acknowledgements. This work has been supported by the EU financed project FLASH (Contract No. 036852). The authors thank the reviewers for their constructive comments.

Summary

The distribution and the number of lightning are related with the presence of ice, the strength of the updraft within the convective clouds as well as their vertical development. The www.nat-hazards-earth-syst-sci.net/9/1719/2009/

Edited by: S. Michaelides, K. Savvidou, and F. Tymvios Reviewed by: two anonymous referees

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