JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, D19302, doi:10.1029/2010JD015509, 2011
Influences of the springtime northern Indian biomass burning over the central Himalayas Rajesh Kumar,1,2 Manish Naja,1,2 S. K. Satheesh,3 N. Ojha,1 H. Joshi,1 T. Sarangi,1 P. Pant,1 U. C. Dumka,1 P. Hegde,4 and S. Venkataramani5 Received 15 December 2010; revised 7 July 2011; accepted 18 July 2011; published 6 October 2011.
[1] The influences of the springtime northern Indian biomass burning are shown for the first time over the central Himalayas by using three years (2007–2009) of surface and space based observations along with a radiative transfer model. Near‐surface ozone, black carbon (BC), spectral aerosol optical depths (AODs) and the meteorological parameters are measured at a high altitude site Nainital (29.37°N, 79.45°E, 1958 m amsl) located in the central Himalayas. The satellite observations include the MODIS derived fire counts and AOD (0.55 mm), and OMI derived tropospheric column NO2, ultraviolet aerosol index and single scattering albedo. MODIS fire counts and BC observations are used to identify the fire‐impacted periods (372 h during 2007–2009) and hence the induced enhancements in surface BC, AOD (0.5 mm) and ozone are estimated to be 1802 ng m−3 (∼145%), 0.3 (∼150%) and 19 ppbv (∼34%) respectively. Large enhancements (53–100%) are also seen in the satellite derived parameters over a 2° × 2° region around Nainital. The present analysis highlights the northern Indian biomass burning induced cooling at the surface (−27 W m−2) and top of the atmosphere (−8 W m−2) in the lesser polluted high altitude regions of the central Himalayas. This cooling leads to an additional atmospheric warming of 19 W m−2 and increases the lower atmospheric heating rate by 0.8 K day−1. These biomass burning induced changes over the central Himalayan atmosphere during spring may also lead to enhanced short‐wave absorption above clouds and might have an impact on the monsoonal rainfall. Citation: Kumar, R., M. Naja, S. K. Satheesh, N. Ojha, H. Joshi, T. Sarangi, P. Pant, U. C. Dumka, P. Hegde, and S. Venkataramani (2011), Influences of the springtime northern Indian biomass burning over the central Himalayas, J. Geophys. Res., 116, D19302, doi:10.1029/2010JD015509.
1. Introduction [2] Biomass burning has been recognized as an important source of several trace species (both gases and aerosols) on local to regional and global scales [Crutzen and Andreae, 1990; Galanter et al., 2000; Thompson et al., 2001; Andreae and Merlet, 2001]. The trace species released by the biomass burning and the byproducts (e.g., ozone and secondary aerosols) of the reactions among these species are now well recognized for their contribution in the air quality degradation [e.g., Galanter et al., 2000; Andreae and Merlet, 2001; Pfister et al., 2008] and the radiation budget perturbation [e.g., Duncan et al., 2003; Stone et al., 2008]. Biomass 1
Aryabhatta Research Institute of Observational Sciences, Nainital, India. Department of Physics, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India. 3 Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, India. 4 Space Physical Laboratory, Vikram Sarabhai Space Centre, Trivandrum, India. 5 Physical Research Laboratory, Ahmedabad, India. 2
Copyright 2011 by the American Geophysical Union. 0148‐0227/11/2010JD015509
burning has also been shown to increase the tropospheric background levels of different species such as CO [e.g., Novelli et al., 2003]. [3] In light of these important roles played by the biomass burning, numerous efforts have been made to understand its impact on the atmospheric composition, the budget of trace species [e.g., Andreae and Merlet, 2001; Duncan et al., 2003] and the physical and chemical processes occurring during the transport of its plumes [e.g., Poppe et al., 1998; Jaffe et al., 2004]. However, such efforts were largely confined to Africa, Australia, Southeast Asia and the USA [e.g., Poppe et al., 1998; Takegawa et al., 2003; Pochanart et al., 2003; Kondo et al., 2004; Pfister et al., 2008] and are scarce over the South Asia where biomass burning contributes significantly to the budget of the trace species [e.g., Galanter et al., 2000; Lelieveld et al., 2001] and thereby affecting the radiation budget and atmospheric chemistry over this tropical region. [4] In contrast to the other tropical (e.g., Africa) and extra‐ tropical (e.g., boreal forests) regions, agricultural fires (116– 289 Tg/year) burn much more biomass annually than the forest fires (32–61 Tg/year) over India [Venkataraman et al., 2006]. Due to differences in the biomass types, pyrogenic
D19302
1 of 14
D19302
KUMAR ET AL.: INFLUENCES OF FIRES OVER THE HIMALAYAS
emissions in this region are expected to be different from other regions. In addition, the use of bio‐fuels in domestic cooking further augments the diversity of emissions in the Indian region. Here, it is also important to note that the biomass and bio‐fuel burning sources in this region are co‐located in close proximity of fossil‐fuel burning sources. Such a coincidence of these emission sources lead to the chemical processes that may differ from those in the other parts of world where either of these emissions dominates over a region as shown during Indian Ocean Experiment (INDOEX) [Lelieveld et al., 2001; Reiner et al., 2001]. For example, Dickerson et al. [2002] reported that unlike North American and European outflows, ozone concentrations in South Asian outflow are lower despite very high pollution loadings. [5] Different space‐based observations over the Indian region [Fishman et al., 2003; Jethva et al., 2005] exhibit highest pollution loadings over the Indo‐Gangetic Plain (IGP) region situated in northern India indicating wider range of anthropogenic activities in this region. This region also provides favorable climate for the agricultural activities due to its fertile soils and abundant water supply from the southwest monsoon and the rivers originating from the Himalayan glaciers such as the Ganges. Consequently, the cultivable land forms a major fraction of the total geographical area in the IGP region (∼76%) as compared to the rest of India (∼50%) (http://dacnet.nic.in/). In this large area of agricultural land, the crop residues left after the harvesting practices during spring are subjected to the fires and contribute to emissions in this region. [6] The enhanced pollution over this region during spring is shown to alter the strength of monsoonal rainfall [e.g., Lau and Kim, 2010]. BC emitted by the fires may also deposit onto the snow and can exacerbate the melting of glaciers by reducing the snow albedo. It is shown that BC from the IGP region can reach to the altitudes of Himalayan glaciers and reduces the snow albedo during spring [Yasunari et al., 2010, and references therein]. Despite these plausible consequences of fires, mitigation policies over India generally ignore the role of biomass burning. [7] In the above scenario, the present study is the first attempt aimed at identifying the impact of the northern Indian biomass burning on the trace species and radiation budget over the central Himalayas by using the surface and satellite observations, back‐air trajectories and results from a radiative transfer model. The manuscript provides a general description of the study region, general meteorology and the observation site in the section 2. The details of the different ground and space based instruments and the models used in this study are given in the section 3. The results are presented in the section 4 and the conclusions from this study are given in the section 5.
2. The Study Region and Observation Site [8] The geographical region from 24°N to 34°N and from 65°E to 86°E is defined as the study region and is designated as the “Northern Indian Subcontinent.” The topography of the study region in the Indian subcontinent is shown in Figure 1a. The northeastern sector of the study region encompasses the higher altitude (>1000 m amsl) Himalayan mountain ranges while the rest of the regions are low alti-
D19302
tude (2.0.CO;2. Sagar, R., B. Kumar, U. C. Dumka, K. K. Moorthy, and P. Pant (2004), Characteristics of aerosol optical depths over Manora Peak: A high altitude station in the central Himalayas, J. Geophys. Res., 109, D06207, doi:10.1029/2003JD003954.
D19302
Satheesh, S. K., and J. Srinivasan (2006), A method to estimate aerosol radiative forcing from spectral optical depths, J. Atmos. Sci., 63, 1082–1092, doi:10.1175/JAS3663.1. Satheesh, S. K., V. Ramanathan, B. N. Holben, K. K. Moorthy, N. G. Loeb, H. Maring, J. M. Prospero, and D. Savoie (2002), Chemical, microphysical and radiative effects of Indian Ocean aerosols, J. Geophys. Res., 107(D23), 4725, doi:10.1029/2002JD002463. Sheridan, P. J., et al. (2005), The Reno aerosol optics study: Overview and summary of the results, Aerosol Sci. Technol., 39, 1–16, doi:10.1080/ 027868290901891. Stone, R. S., G. P. Anderson, E. P. Shettle, E. Andrews, K. Loukachine, E. G. Dutton, C. Schaaf, and M. O. Roman III (2008), Radiative impact of boreal smoke in the Arctic: Observed and modeled, J. Geophys. Res., 113, D14S16, doi:10.1029/2007JD009657. Stroppiana, D., S. Pinnock, and J.‐M. Grégoire (2000), The Global Fire Product: Daily fire occurrence from April 1992 to December 1993 derived from NOAA AVHRR data, Int. J. Remote Sens., 21, 1279–1288, doi:10.1080/014311600210173. Takegawa, N., et al. (2003), Photochemical production of O3 in biomass burning plumes in the boundary layer over northern Australia, Geophys. Res. Lett., 30(10), 1500, doi:10.1029/2003GL017017. Thompson, A. M., et al. (2001), Tropical tropospheric ozone and biomass burning, Science, 291, 2128–2132, doi:10.1126/science.291.5511.2128. Venkataraman, C., G. Habib, D. Kadamba, M. Shrivastava, J.‐F. Leon, B. Crouzille, O. Boucher, and D. G. Streets (2006), Emissions from open biomass burning in India: Integrating the inventory approach with high‐ resolution Moderate Resolution Imaging Spectroradiometer (MODIS) active‐fire and land cover data, Global Biogeochem. Cycles, 20, GB2013, doi:10.1029/2005GB002547. Weingartner, E., et al. (2003), Absorption of light by soot particles: Determination of the absorption coefficients by means of aethalometers, J. Aerosol Sci., 34, 1445–1463, doi:10.1016/S0021-8502(03)00359-8. Yamaji, K., et al. (2010), Impact of open crop residual burning on air quality over central eastern China during the Mount Tai Experiment 2006 (MTX 2006), Atmos. Chem. Phys., 10, 7353–7368, doi:10.5194/acp10-7353-2010. Yasunari, T. J., et al. (2010), Estimated impact of black carbon deposition during pre‐monsoon season from Nepal Climate Observatory—Pyramid data and snow albedo changes over Himalayan glaciers, Atmos. Chem. Phys., 10, 6603–6615, doi:10.5194/acp-10-6603-2010. Zeng, J., Y. Tohjima, Y. Fujinuma, H. Mukai, and M. Katsumoto (2003), A study of trajectory quality using methane measurements from Hateruma Island, Atmos. Environ., 37, 1911–1919, doi:10.1016/S1352-2310(03)00048-7. U. C. Dumka, H. Joshi, R. Kumar, M. Naja, N. Ojha, P. Pant, and T. Sarangi, Aryabhatta Research Institute of Observational Sciences, Nainital 263129, India. (
[email protected]) P. Hegde, Space Physical Laboratory, Vikram Sarabhai Space Centre, Trivandrum 263129, India. S. K. Satheesh, Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore 560012, India. S. Venkataramani, Physical Research Laboratory, Ahmedabad 380009, India.
14 of 14
