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Changes in Persistent and Non-Persistent Flood Season Precipitation over South China During 1961–2010 WU Hui1,2 (
) and ZHAI Panmao2∗ (
)
1 Hainan Climate Center, Haikou 570203 2 State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081 (Received June 20, 2013; in final form September 22, 2013)
ABSTRACT The characteristics and possible causes of changes in persistent precipitation (PP) and non-persistent precipitation (NPP) over South China during flood season are investigated using daily precipitation data from 63 stations in South China and NCEP/NCAR reanalysis data from 1961 to 2010. This investigation is performed using the Kendall’s tau linear trend analysis, correlation analysis, abrupt climate change analysis, wavelet analysis, and composite analysis techniques. The results indicate that PP dominates total precipitation over South China throughout the year. The amounts of PP and NPP during flood season vary primarily on a 2–5-yr oscillation. This oscillation is more prominent during the early flood season (EFS; April–June). NPP has increased significantly over the past 50 years while PP has increased slightly during the whole flood season. These trends are mainly due to a significant increase in NPP during the EFS and a weak increase in PP during the late flood season (LFS; July–September). The contribution of EFS NPP to total flood season precipitation has increased significantly while the contribution of EFS PP has declined. The relative contributions of both types of precipitation during LFS have not changed significantly. The increase in EFS NPP over South China is likely related to the combined effects of a stronger supply of cold air from the north and a weaker supply of warm, moist air from the south. The increase in NPP amount may also be partially attributable to a reduction in the stability of the atmosphere over South China. Key words: persistent precipitation, non-persistent precipitation, climate change, South China Citation: Wu Hui and Zhai Panmao, 2013: Changes in persistent and non-persistent flood season precipitation over South China during 1961–2010. Acta Meteor. Sinica, 27(6), 788–798, doi: 10.1007/s13351-013-0613-x.
1. Introduction Changes in climate extremes have attracted increasing attention during recent decades because extreme events often exert a greater influence on natural and human ecosystems than mean climate (Katz and Brown, 1992; Aguilar et al., 2009). Daily temperature and precipitation data have been widely used to study changes in regional climate extremes since the late 1990s. Analysis of these daily observations has revealed important trends (Karl and Easterling, 1999; Zhai et al., 1999). Alexander et al. (2006) recently analyzed changes in temperature and precipitation extremes on global scale. IPCC (2007) reported that precipitation increased significantly between 1900
and 2005 over the eastern parts of North and South America, northern Europe, and northern and central Asia, while decreased over the Sahel, the Mediterranean, southern Africa, and parts of southern Asia. The frequency of heavy precipitation events has likely increased over most areas during the last 50 years, as has the proportion of total rainfall that occurs in heavy precipitation events. China is located in the East Asian monsoon region, where the characteristics of changes in precipitation vary greatly by location. Many previous studies have discussed the possible causes of precipitation changes in China (e.g., Yu et al., 2004; Yu and Zhou, 2007; Zhou et al., 2009). Yu et al. (2004) ascribed some changes in precipitation over China to a weaken-
Supported by the National (Key) Basic Research and Development (973) Program of China (2012CB417205) and National Science and Technology Support Program of China (2013BAK05B03). ∗ Corresponding author:
[email protected]. ©The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg 2013
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ing of the summer monsoon over East Asia, including changes in the three-dimensional large-scale tropospheric circulation and upper troposphere temperature. Yu and Zhou (2007) and Zhou et al. (2009) pointed out that this weakening of the East Asian summer monsoon is part of an interdecadal variation in climate. This interdecadal signal exists throughout the year but is most robust in spring and summer. Changes in extreme precipitation are substantially different between northern and southern China (Zhai et al., 1999, 2005, 2007; Yan and Yang, 2000; Qian et al., 2007; Ren et al., 2010). Although the trend in total precipitation over all of China was small from 1951 to 2000, precipitation decreased significantly over the southern part of Northeast China, North China, and Sichuan basin, while it increased significantly over western China, the Yangtze River valley, and along the southeastern coast. The number of rainy days has decreased substantially in most parts of China, even though the precipitation intensity has increased (Zhai et al., 2005). Studies on changes in precipitation events of different intensities indicate that the increase in total precipitation from 1960 to 2003 was mainly attributable to an increase in extreme precipitation, while the decrease in the number of rainy days was due to a reduction in the occurrence frequency of very light rain. The ratio of extreme precipitation to total precipitation increased over most areas of China (Min and Qian, 2008). A significant increase in heavy precipitation was the primary driver of the increase in total precipitation between 1957 and 2004 (Wang and Zhai, 2008). Bai et al. (2007) showed significant decreases in the number of days during wet spells in North China, central China, and Southwest China between 1953 and 2003. Meanwhile, the amount of annual precipitation occurring during wet spells decreased significantly in North China, eastern Northeast China, and eastern Southwest China. Huang et al. (2011) reported that the number of precipitation events with durations longer than 5 days has reduced significantly since 2000, while continuous precipitation events with durations of 2 or 3–4 days have become more frequent during the Meiyu season in the Yangtze-Huai River valley.
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The Yangtze River valley and South China are the parts of China most affected by persistent heavy precipitation. In the Yangtze River valley, these persistent heavy precipitation events occur mostly during the Meiyu season from mid June to mid July (Chen, 2004; Ding et al., 2007). In South China, the flood season lasts long enough that it can be divided into two sub-periods: the early flood season (EFS; April–June) and the late flood season (LFS; July–September). Precipitation during the EFS is strongly related to largescale westerly frontal systems, low-level jet, and southern trough. Rainfall during the LFS is principally attributable to tropical weather systems such as the Intertropical Convergence Zone (ITCZ) and tropical cyclones (Wu et al., 1990). Changes in the climatology of extreme precipitation events over South China have been noticed. The results of recent studies have indicated that five out of six sub-regions of South China have experienced significant increases in the frequency of extreme precipitation during summer (Lu et al., 2010). The number of torrential rain days in South China has also increased slightly during both the EFS and the LFS (Wu et al., 2011). Persistent precipitation (PP) represents precipitation that occurs during wet spells. Non-persistent precipitation (NPP) represents all other precipitation, and provides an additional perspective on changes in the water cycle. It is therefore helpful to analyze both metrics to more fully understand changes in the climatological features of extreme precipitation and precipitation as a whole. This study provides an analysis of the changes in PP and NPP events over South China during the flood season using by daily rainfall data. It will help to understand how and why extreme precipitation has changed in South China. The paper is organized as follows. We introduce the data and methodology in Section 2, present the features of and changes in the climatologies of PP and NPP in Section 3, and discuss the implications of the results in Section 4. 2. Data and methods 2.1 Data The precipitation data used in this study come
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from observations of daily rainfall at 756 surface stations in China. These data were collected and screened for quality by the National Meteorological Information Center of the China Meteorological Administration (CMA). The analysis is based on data taken between 1961 and 2010 at 63 stations spaced approximately uniformly across South China in Guangdong Province, Hainan Province, Guangxi Region, and the areas of Fujian Province south of 26◦ N. Atmospheric reanalysis data (including relative humidity, temperature, and winds at 500 and 850 hPa) are taken from the NCEP/NCAR reanalysis from 1968 to 2010. The NCEP/NCAR reanalysis data are currently available from January 1948; however, we have chosen to limit the focus period because the quality of the reanalysis over Asia may be low prior to 1968 (Yang et al., 2002). 2.2 Methods Precipitation events are classified as either PP or NPP based on the definitions applied by Martin-Vide and Gomez (1999) and Tolika and Maheras (2005). A PP event is defined as any event with daily rainfall > 0.1 mm over duration of at least 3 days. All other rainfall events are classified as NPP events. The early flood season (EFS) is defined as the period from April to June, while the late flood season (LFS) is defined as the period from July to September (Li et al., 2002). The ratio of the precipitation amount during a given period to the total precipitation amount over the flood season (April–September) is referred to as the contribution of this period. The climate change signals in precipitation are
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evaluated as linear trends using Kendall’s tau (Sen, 1968; Zhai et al., 2005). Possible autocorrelation in the time series is removed using an iterative procedure introduced by Zhang et al. (2000) and refined by Wang and Swail (2001). Trends are assessed for statistical significance at the 5% level. The Morlet wavelet analysis technique (Torrence and Compo, 1998) is used to analyze the characteristics of variations in the time series of both types of precipitation during the flood season. The abrupt climatic change test for precipitation is conducted with both Mann-Kendall and Student’s t-test. The latter test is applied to 11 shorter time series of length 5–15 yr (Fu and Wang, 1992). Vertical gradients in pseudo-equivalent potential temperatures between lower (850 hPa) and upper (500 hPa) levels over South China are used to define the atmospheric instability. The atmosphere is considered convectively unstable when ∆θse = θse850 − θse500 is greater than 0. 3. Climatology and trends of persistent and non-persistent precipitation in flood season 3.1 Climatology Most of the rainfall over South China occurs as PP (Fig. 1), with contributions to total monthly precipitation ranging from 67% (December) to 88.5% (June). The PP during the EFS represents 42.4% of the total flood season precipitation, while PP during the LFS contributes 41.3%.
Fig. 1. Monthly variations of total precipitation (TP), persistent precipitation (PP), and non-persistent precipitation (NPP) over South China. The ratios of PP and NPP to TP are also shown.
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As in many monsoon regions, there is a sharp peak in the annual cycle of total precipitation (Zhou et al., 2008), but monthly mean PP and NPP amounts both peak twice during the year over South China. The main peak of PP occurs in June while that of NPP occurs in May. The secondary peaks of both types of precipitation occur in August. The annual cycle of precipitation over South China is similar to the annual cycle of wet spells presented by Bai et al. (2007). 3.2 Climate variations 3.2.1 Interannual variability Wavelet analysis reveals not only the local features of precipitation but also its periodic variations. This is useful for understanding the detailed characteristics of how and why precipitation varies. Both types of precipitation principally vary on periods of
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2–5 yr during flood season in South China, but their changes are not necessarily consistent. PP oscillated on a quasi-2-yr cycle during the early and mid 1970s but on a quasi-4-yr cycle after the 1990s (Fig. 2a). NPP oscillated on a quasi-2-yr cycle from the mid 1960s to the mid 1970s and a quasi-5-yr cycle after the 1990s (Fig. 2c). This latter oscillation was accompanied by an increase in the NPP amount after the 1990s (Fig. 2b). The synoptic systems affecting precipitation are different during the EFS and the LFS in South China, so we have also applied the wavelet analysis technique to both types of precipitation during different sub-periods of the flood season (figure omitted). The oscillations in PP and NPP averaged over the full flood season were more similar to those during the EFS. Variations in these two types of precipitation during the flood season in South China were influenced primarily by variability on interannual timescales, es-
Fig. 2. (a, c) Wavelet power spectra and (b) time series of PP (top) and NPP (bottom) amounts during flood season in South China. In the wavelet power spectrum maps (a, c), contours indicate the wavelet power spectra and shading indicates areas significant at the 95% confidence level; dotted lines mark the areas of the spectra influenced by edge effects.
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pecially the variability that affected precipitation during the EFS. 3.2.2 Climate trends Trends in both types of precipitation amount have been calculated and are presented in this section. The area-averaged amount of PP during flood season in South China increased weakly at a rate of 5.4 mm (approximately 0.5%) per decade between 1961 and 2010. The amount of NPP increased more substantially, at a rate of 9.4 mm (approximately 4.4%) per decade. Table 1 lists the characteristics of the trends in PP and NPP for the full flood season, EFS, and LFS. Area-averaged PP during the EFS in South China decreased slightly at a rate of –2.7 mm (approximately –0.5%) per decade, while NPP during the EFS increased significantly at a rate of 7.8 mm (approximately 6.9%) per decade. Precipitation during EFS and LFS varied on both interannual and interdecadal timescales (Fig. 3). PP during EFS was generally smaller in the early 1960s and between the mid 1980s and the early 2000s. These periods include particularly dry years such as 1963 and 1995 (the lowest value was 257.7 mm in 1963). PP was relatively abundant from the mid 1970s to the early 1980s and in the mid and late 2000s, with very wet years in 1973 and 2008 (the peak value was 766.4 mm in 1973). NPP during the EFS was relatively small during the early 1960s to the early 1990s, and then increased substantially after the 1990s. Both types of rainfalls increased weakly during the LFS in South China since 1961 (Fig. 4), with PP increasing at a rate of 8.1 mm (about 1.5%) per decade and NPP increasing at a rate of 1.6 mm (approximately 1.6%) per decade. PP was relatively light from the early 1960s to the early 1970s and from the early 1980s to the early 1990s (with a minimum of 338.8 mm in 1989), and was relatively abundant from the mid 1970s to the early 1980s and from the mid 1990s to the early 2000s (with a maximum of 844.7 mm in 1994). NPP was relatively abundant in the early and mid 1960s and after the 1980s, with a deficit from the late 1960s to the early 1980s (with a minimum in 1976 and a maximum in 2008). Analysis using the Mann-Kendall test and Student’s t-test indicates that abrupt climate change
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points occurred in 1992 for NPP over the full flood season and during the EFS. No abrupt climate change points were identified for NPP during the LFS or for PP during any sub-period of the flood season. The significant increase in precipitation associated with NPP events during the flood season since 1992 was mainly due to an increase in NPP during the EFS. By contrast, the slight increase in precipitation associated with PP events during the flood season resulted from a weak increase in PP during the LFS. Trends in the two types of precipitation over South China between 1961 and 2010 had distinct spatial patterns. PP during the EFS had not changed much over most areas of South China (Fig. 5a). NPP during the EFS changed significantly at nearly 20% of observation stations, particularly in the coastal areas of Guangdong and Fujian provinces. PP during the LFS increased significantly along part of the southern coast of Fujian Province, but decreased in some areas
Fig. 3. Time series of area-averaged PP (filled circles) and NPP (empty circles) during the early flood season (EFS) in South China from 1961 to 2010. The thin solid and thick dash-dotted lines represent binomial 11-point smoothing of the PP and NPP time series, respectively.
Fig. 4. As in Fig. 3, but for the late flood season (LFS).
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Table 1. Trends in persistent and non-persistent flood season precipitation over South China Flood season (April–September) Total PP NPP 14.8 5.4 9.4 1296 1084 212 1.1 0.5 4.4 –0.5 0.5
Early flood season (April–June) Total PP NPP 5.1 –2.7 7.8 660 546 114 0.8 –0.5 6.9 –0.1 –0.6 0.5
Rainfall trend: b1 (mm per decade) Annual average rainfall: a1 (mm) Percentage trend of rainfall: b2 (% per decade) Trend contribution relative to rainfall in flood season: b3 (% per decade) Note: b2 = b1/a1×100%. Underlined values are significant at the 95% confidence level.
Late flood season (July–September) Total PP NPP 9.7 8.1 1.6 636 538 98 1.2 1.5 1.6 0.1 0.1 0.0
Fig. 5. Spatial distribution of trends in PP (black) and NPP (red) over South China during the (a) EFS and (b) LFS. Empty circles indicate the lack of a significant trend. Solid circles indicate a significant increasing trend and solid squares indicate a significant decreasing trend.
of Guangxi Region (Fig. 5b). Significant increases in NPP during the LFS occurred at only 8% of stations, mainly along the Guangxi coast, in the mountainous central district of Hainan, and in southern Guangdong Province. Changes in the relative contributions of each type of precipitation to the total precipitation amount are
shown in Fig. 6. The relative contribution of PP to total flood season precipitation has decreased significantly since 1961, at a rate of approximately –0.5% per decade (Table 1). The relative contribution of NPP has accordingly increased at a rate of approximately 0.5% per decade. The contribution of EFS PP to total flood season precipitation decreased weakly over this
Fig. 6. Relative contributions of persistent and non-persistent precipitation to total flood season precipitation during the (a) EFS and (b) LFS from 1961 to 2010. Linear trends in the relative contributions of PP and NPP are shown as solid and dotted lines, respectively.
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period, while that of EFS NPP increased significantly at a rate of approximately 0.5% per decade (Fig. 6a). Changes in the relative contributions of both types of LFS precipitation were small during this period (Fig. 6b). 3.3 Possible causes of changes in EFS NPP The above analysis indicates that EFS NPP increased substantially over South China during 1961– 2010. This change is one of the most important components of the change in total flood season precipitation over South China and is examined further in this section. Precipitation over South China during the EFS is mainly frontal precipitation in origin before the outbreak of the South China Sea Monsoon (SCSM). This situation changes after the outbreak of the SCSM, when the dominant form of precipitation in South China is convective precipitation associated with the summer monsoon. The mean climatological onset date for summer monsoon rainfall over South China has been derived as 24 May (Zheng et al., 2006). We therefore speculate that the significant increase in EFS NPP over South China has been caused primarily by an increase in frontal and/or convective precipitation during the EFS. Frontal rainfall is associated with the convergence of cold air from higher latitudes and warm air from lower latitudes. We select northerly wind as an indicator of cold air incursions following Yang et al. (2002) and Yao and Yu (2005). As discussed in Section 3.2.2, abrupt climate change point occurred in 1992 for NPP during the EFS. We therefore divide the analysis period into two sub-periods: 1968–1991 and 1992–2010. Figure 7a shows differences in the average EFS meridional winds between these two periods (later minus earlier). It is found that the regions with negative differences cover areas from South China to the South China Sea, and the regions with significant changes are mainly over the western part of South China. This result indicates an increase in the supply of cold air from higher latitudes and a decrease in the supply of warm air from lower latitudes since 1992. Examination of a time-latitude cross-section of mean meridional wind
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at 850 hPa averaged over 100◦ –120◦ E (figure omitted) also supports the conclusion that northerly winds strengthened and southerly winds weakened during this period, leading to weaker convergence between cold and warm air over South China. This decrease in convergence was unfavorable for PP, and therefore enhanced the relative importance of NPP over South China during the EFS. Figure 7a suggests that an increased relative contribution from NPP is associated with a stronger supply of cold, dry air and a weaker supply of warm, moist air to the east of 100◦ E. By contrast, the years with an increased relative contribution from PP tend to have a weaker supply of cold, dry air from the north and a stronger supply of warm, moist air from the south (figure omitted). The relative contribution of EFS NPP to total flood season precipitation over South China therefore appears to be closely related to lowlevel meridional winds over South China. The correlation coefficient between EFS NPP and area-averaged (20.0◦ –27.5◦ N, 100◦ –117.5◦ E) meridional winds at 850 hPa is large (–0.46) and statistically significant, supporting this conclusion. Linear trend analyses identify significant decreases in meridional winds at 850 hPa over South China (Fig. 7b), further confirming that the supply of warm, moist air from the south has weakened over this period. Meridional winds over South China and simultaneous NPP at stations in South China are also negatively correlated during the EFS. These correlations are most significant at stations in Fujian and Guangdong provinces (Fig. 7c); with a spatial pattern similar to the spatial pattern of trends in EFS NPP (Fig. 5a). Convective precipitation is tied to atmospheric stability. Figure 7d shows the spatial distribution of differences in atmospheric stability during the EFS between 1992–2010 and 1968–1991. The atmospheric instability ∆θse (see Section 2.2) was larger during 1992–2010 than during 1968–1991 over most parts of South China. This result suggests that the atmosphere was more convectively unstable after the early 1990s. These differences were most significant (at the 95% confidence level) over the southeastern coast of South China and the South China Sea. During the entire
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period of 1968–2010 (Fig. 7e), the area-averaged atmospheric stratification over South China in the EFS became significantly less stable (at the 99% confidence level). Atmospheric instability and EFS NPP
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averaged over South China were indistinctive positively correlated during this period. The relationship between changes in NPP and the intensification of convective instability over the southeastern coast of
Fig. 7. (a) Difference in mean meridional wind (m s−1 ) at 850 hPa between 1992–2010 and 1968–1991; (b) time series of EFS NPP (mm) and 850-hPa meridional wind (m s−1 ) averaged over South China; (c) spatial distribution of the correlation between NPP observed at each station and 850-hPa meridional wind averaged over South China; (d) difference in atmospheric stratification (×10−2 K hPa−1 ) between 1992–2010 and 1968–1991 in EFS over South China; (e) time series of EFS NPP (mm) and atmospheric stratification (×10−2 K hPa−1 ) averaged over South China; and (f) spatial distribution of the correlation between NPP observed at individual stations and atmospheric stratification averaged over South China. Shaded areas in (a) and (d) indicate statistically significant differences. Red and black dots in (c) and (f) indicate statistically significant negative and positive correlations, respectively, while empty circles indicate no significant correlation.
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South China is also reflected in the map of correlation coefficient between regionally-averaged ∆θse and observed EFS NPP at individual stations in South China (Fig. 7f). In summary, the significant increase in the importance of NPP during the EFS in South China between 1961 and 2010 is mainly attributable to a stronger supply of cold air to South China from the north and a weaker supply of warm, moist air from the south. A reduction in atmospheric stability over South China also established a favorable background for the increase in NPP. 4. Conclusions and discussion Precipitation events during the flood season in South China have been classified into two types: persistent precipitation (PP) and non-persistent precipitation (NPP). The trends in these two types of precipitation and their relative contributions to total flood season precipitation have been calculated and presented. Differences in these trends between the early flood season (EFS) and late flood season (LFS) have also been investigated. The characteristics of changes in flood season precipitation over South China between 1961 and 2010 are concluded as follows. PP is the primary type of precipitation during the flood season in South China; however, PP amounts increased only slightly over the analysis period, while NPP amounts increased significantly over the past 50 years. These changes are attributable to a significant increase in NPP amounts during the EFS and a weak increase in PP amounts during the LFS. The relative contribution of EFS NPP to total flood season precipitation has increased significantly while the relative contribution of EFS PP has declined. The relative contributions of both types of rainfall during LFS to total flood season precipitation have remained approximately steady. A preliminary investigation into the causes of the significant increase in EFS NPP over South China suggests that the increase was mainly due to an increased supply of cold air from the north and a reduced supply of warm, moist air from the south. A reduction in the stability of the atmosphere
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over South China also established a favorable background for the increase in NPP. Precipitation in South China is also strongly affected by tropical cyclone activity. The volume of tropical cyclone precipitation (TCP), the annual frequency of torrential TCP events, and the relative contribution of TCP to annual precipitation in China have all decreased in recent years (Ren et al., 2006). The number of the tropical cyclones landing on the coastal areas of South China also shows a decreasing trend (Zhang et al., 2012). The relationship between changes in tropical cyclone activity and changes in PP and NPP over South China requires a further study in the future. Acknowledgments. The language editor for this manuscript is Dr. Jonathon S. Wright.
REFERENCES Aguilar, E., A. A. Barry, M. Brunet, et al., 2009: Changes in temperature and precipitation extremes in western central Africa, Guinea Conakry, and Zimbabwe, 1955–2006. J. Geophys Res., 114(D2), doi: 10.1029/2008JD011010. Alexander, L. V., X. Zhang, T. C. Peterson, et al., 2006: Global observed changes in daily climate extremes of temperature and precipitation. J. Geophys. Res., 111(D5), doi: 10.1029/2005JD006290. Bai, A. J., P. M. Zhai, and X. D. Liu, 2007: Climatology and trends of wet spells in China. Theor. Appl. Climatol., 88, 139–148. Chen, G. T. J., 2004: Research on the phenomena of Meiyu during the past quarter century: An overview. East Asian Monsoon. World Scientific, 560 pp. Ding Yihui, Liu Junjie, Sun Ying, et al., 2007: A study of the synoptic-climatology of the Meiyu system in East Asia. Chinese J. Atmos. Sci., 31(6), 1082– 1101. (in Chinese) Fu Congbin and Wang Qiang, 1992: The definition and detection of the abrupt climatic change. Chinese J. Atmos Sci., 16(4), 482–492. (in Chinese) Huang, D. Q., J. Zhu, and X. Y. Kuang, 2011: Decadal variation of different durations of continuous Meiyu precipitation and the possible cause. Chinese Sci. Bull., 56(4–5), 424–431. IPCC, 2007: Climate Change 2007: Synthesis Report. Contribution of Working Group I, II and III to the
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797
Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Core Writing Team, Pachauri, R. K., and A. Reisinger, Eds., IPCC, Geneva, Switzerland, 104 pp.
Wang, X. L., and V. R. Swail, 2001: Changes of extreme wave heights in Northern Hemisphere oceans and related atmospheric circulation regimes. J. Climate, 14(10), 2204–2221.
Karl, T. R., and D. R. Easterling, 1999: Climate extremes: Selected review and future research directions. Climatic Change, 42, 309–325.
Wang Xiaoling and Zhai Panmao, 2008: Changes in China’s precipitation in various categories during 1957–2004. J. Trop. Meteor., 24(5), 459–466. (in Chinese)
Katz, R. W., and B. G. Brown, 1992: Extreme events in a changing climate: Variability is more important than averages. Climatic Change, 21, 289–302. Li Jiangnan, Wang Anyu, Meng Weiguang, et al., 2002: The climatological characteristics of precipitation of the presummer rainy reason and second rainy season in Guangdong Province. Acta Scientiarum Naturalium Universitatis Sunyatseni, 41(3), 91–94. (in Chinese)
Wu Hongyu, Du Yaodong, and Qin Peng, 2011: Climate characteristics and variation of rainstorm in South China. Meteor. Mon., 37(l0), 1262–1269. (in Chinese) Wu Shangsen, Huang Chengchang, and Xue Huixian, 1990: On interannual variation of precipitation during the second rainy season in South China. J. Trop. Meteor., 6(4), 348–356. (in Chinese)
Lu Hong, He Hui, and Chen Sirong, 2010: Spatiotemporal variation of extreme precipitation frequency in summer over South China in 1961–2008. Chinese Journal of Ecology, 29(6), 1213–1220. (in Chinese)
Yan Zhongwei and Yang Chi, 2000: Geographic patterns of extreme climate changes in China during 1951– 1997. Climatic Environ. Res., 5(3), 267–272. (in Chinese)
Martin-Vide, J., and L. Gomez, 1999: Regionalization of Peninsular Spain based on the length of dry spells. Int. J. Climatol., 19, 537–555.
Yang, S., K. M. Lau, and K. M. Kim, 2002: Variations of the East Asian jet stream and Asian-PacificAmerican winter climate anomalies. J. Climate, 15, 306–325.
Min Shen and Qian Yongfu, 2008: Trends in all kinds of precipitation events in China over the past 40 years. Acta Scientiarum Naturalium Universitatis Sunyatseni, 47(3), 105–111. (in Chinese) Qian Weihong, Fu Jiaolan, Zhang Weiwei, et al., 2007: Changes in mean climate and extreme climate in China during the last 40 years. Adv. Earth Sci., 22(7), 673–684. (in Chinese) Ren, F. M., G. X. Wu, W. J. Dong, et al., 2006: Changes in tropical cyclone precipitation over China. Geophys. Res. Lett., 33(20), doi: 10.1029/2006GL027951. Ren Guoyu, Feng Guolin, and Yan Zhongwei, 2010: Progresses in observation studies of climate extremes and changes in mainland China. Climatic Environ. Res., 15(4), 337–353. (in Chinese) Sen, P. K., 1968: Estimates of the regression coefficient based on Kendall’s tau. J. Am. Sat. Assoc., 63(324), 1379–1389. Tolika, K., and P. Maheras, 2005: Spatial and temporal characteristics of wet spells in Greece. Theor. Appl. Climatol., 81, 71–85. Torrence, C., and G. P. Compo, 1998: A practical guide to wavelet analysis. Bull. Amer. Meteor. Soc., 79, 61–78.
Yao Xiuping and Yu Yubin, 2005: Activity of dry cold air and its impacts on Meiyu rain during the 2003 Meiyu period. Chinese J. Atmos. Sci., 29(6), 973– 985. (in Chinese) Yu, R. C., B. Wang, and T. J, Zhou, 2004: Tropospheric cooling and summer monsoon weakening trend over East Asia. Geophys. Res. Lett., 31, L22212, doi: 10.1029/2004GL021270. —–, and T. J. Zhou, 2007: Seasonality and threedimensional structure of interdecadal change in the East Asian monsoon. J. Climate, 20, 5344–5355. Zhai, P. M., A. J. Sun, F. M. Ren, et al., 1999: Changes of climate extremes in China. Climatic Change, 42, 203–218. —–, X. B. Zhang, H. Wan, et al., 2005: Trends in total precipitation and frequency of daily precipitation extremes over China. J. Climate, 18, 1096–1108. —–, Wang Cuicui, and Li Wei, 2007: A review on study of change in precipitation extremes. Adv. Climate Change Res., 3(3), 144–148. (in Chinese) Zhang, X. B., L. A. Vincent, W. D. Hogg, et al., 2000: Temperature and precipitation trends in Canada during the 20th century. Atmos.-Ocean, 38(3), 395– 429.
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Zhang Junxiang, Liu Xulong, and Gong Qinghua, 2012: Tropical cyclones landing on the coastal areas of South China and related catastrophes over the past 60 years. Tropical Geography, 32(4), 357–363. (in Chinese)
1207–1216. (in Chinese) Zhou, T. J., L. X. Zhang, and H. M. Li, 2008: Changes in global land monsoon area and total rainfall accumulation over the last half century. Geophys. Res. Lett., 35, L16707, doi: 10.1029/2008GL034881.
Zheng Bin, Liang Jianyin, Lin Ailan, et al., 2006: Frontal rain and summer monsoon rain during pre-rainy season in South China. Part I: Determination of the division dates. Chinese J. Atmos. Sci., 30(6),
—–, D. Y. Gong, J. Li, et al., 2009: Detecting and understanding the multi-decadal variability of the East Asian summer monsoon—Recent progress and state of affairs. Meteor. Z., 18(4), 455–467.
