ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-10-4673-2010 How can aerosols affect the Asian summer monsoon? Assessment during three consecutive pre-monsoon seasons from CALIPSO satellite data Kuhlmann J. 1 2 3 Quaas J. 1 Max Planck Institute for Meteorology, Hamburg, Germany TU Dortmund, Dortmund, Germany now at: GFZ German Research Centre for Geosciences, Potsdam, Germany 21 05 2010 10 10 4673 4688 Copyright: © 2010 J. Kuhlmann 2010 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/10/4673/2010/acp-10-4673-2010.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/10/4673/2010/acp-10-4673-2010.pdf

The impact of aerosols above and around the Tibetan Plateau on the Asian Summer Monsoon during pre-monsoon seasons March-April-May 2007, 2008, and 2009 is investigated by means of remote sensing and radiative transfer modelling. Four source regions are found to be responsible for the high aerosol loading around the Tibetan Plateau: the Taklamakan Desert, the Ganges Plains, the Indus Plains, and the Arabian Sea. CALIPSO lidar satellite data, providing vertically resolved images of aerosols, shows aerosol concentrations to be highest in the lower 5 km of the atmosphere with only little amounts reaching the Tibetan Plateau altitude. Using a radiative transfer model we find that aerosol plumes reduce shortwave radiation throughout the Monsoon region in the seasonal average by between 20 and 30 W/m<sup>2</sup>. Peak shortwave heating in the lower troposphere reaches 0.2 K/day. In higher layers this shortwave heating is partly balanced by longwave cooling. Although high-albedo surfaces, such as deserts or the Tibetan Plateau, increase the shortwave heating by around 10%, the overall effect is strongest close to the aerosol sources. A strong elevated heating which could influence large-scale monsoonal circulations as suggested by previous studies is not found.

 References Bollasina, M., Nigam, S., and Lau, K.&nbsp;M.: Absorbing Aerosols and Summer Monsoon Evolution over South Asia: An Observational Portrayal, J. Climate, 21, 3221–3239, 2008. Chung , C. E., Ramanathan, V., Kim, D., and Podgorny, I. A.: Global anthropogenic aerosol direct forcing derived from satellite and ground-based observations, J. Geophys. Res., 110, D24207, https://doi.org/10.1029/2005JD006356, 2005. Collier, J.&nbsp;C. and Zhang, G.&nbsp;J.: Aerosol direct forcing of the summer Indian monsoon as simulated by the NCAR CAM3, Clim. Dynam., 32, 313–332, 2009. Eguchi, K., Uno, I., Yumimoto, K., Takemura, T., Shimizu, A., Sugimoto, N., and Liu, Z.: Trans-pacific dust transport: integrated analysis of NASA/CALIPSO and a global aerosol transport model, Atmos. Chem. Phys., 9, 3137–3145, https://doi.org/10.5194/acp-9-3137-2009, 2009. Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D.&nbsp;W., Haywood, J., Lean, J., Lowe, D.&nbsp;C., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., and Van Dorland, R.: Changes in Atmospheric Constituents and in Radiative Forcing, in: Climate Change 2007 – The Physical Science Basis. Contribution of Working Group&nbsp;I to the Fourth Assessment Report of the IPCC, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.&nbsp;B., Tignor, M., and Miller, H.&nbsp;L., Cambridge University Press, 129–234, 2007. Gautam, R., Hsu, N.&nbsp;C., Lau, K.&nbsp;M., Tsay, S.&nbsp;C., and Kafatos, M.: Enhanced pre-monsoon warming over the Himalayan-Gangetic region from 1979 to 2007, Geophys. Res. Lett., 36, L07704, https://doi.org/10.1029/2009GL037641, 2009a. Gautam, R., Liu, Z., Singh, R.&nbsp;P., and Hsu, N.&nbsp;C.: Two contrasting dust-dominant periods over India observed from MODIS and CALIPSO data, Geophys. Res. Lett., 36, L06813, https://doi.org/10.1029/2008GL036967, 2009b. Gustafsson, O., Krusa, M., Zencak, Z., Sheesley, R.&nbsp;J., Granat, L., Engstrom, E., Praveen, P.&nbsp;S., Rao, P. S.&nbsp;P., Leck, C., and Rodhe, H.: Brown Clouds over South Asia: Biomass or Fossil Fuel Combustion?, Science, 323, 495–498, 2009. Hara, Y., Uno, I., Yumimoto, K., Tanaka, M., Shimizu, A., Sugimoto, N., and Liu, Z.: Summertime Taklimakan dust structure, Geophys. Res. Lett., 35, L23801, https://doi.org/10.1029/2008GL035630, 2008. Haywood, J. and Boucher, O.: Estimates of the Direct and Indirect Radiative Forcing Due to Tropospheric Aerosols: A Review, Rev. Geophys., 38, 513–543, 2000. Huang, J., Minnis, P., Yi, Y., Tang, Q., Wang, X., Hu, Y., Liu, Z., Ayers, K., Trepte, C., and Winker, D.: Summer dust aerosols detected from CALIPSO over the Tibetan Plateau, Geophys. Res. Lett., 34, L18805, https://doi.org/10.1029/2007GL029938, 2007. Huang, J., Minnis, P., Chen, B., Huang, Z., Liu, Z., Zhao, Q., Yi, Y., and Ayers, J.&nbsp;K.: Long-range transport and vertical structure of Asian dust from CALIPSO and surface measurements during PACDEX, J. Geophys. Res.-Atmos., 113, D23212, https://doi.org/10.1029/2008JD010620, 2008. Huang, J., Fu, Q., Su, J., Tang, Q., Minnis, P., Hu, Y., Yi, Y., and Zhao, Q.: Taklimakan dust aerosol radiative heating derived from CALIPSO observations using the Fu-Liou radiation model with CERES constraints, Atmos. Chem. Phys., 9, 4011–4021, https://doi.org/10.5194/acp-9-4011-2009, 2009. Kaufman, Y.&nbsp;J., Tanre, D., and Boucher, O.: A satellite view of aerosols in the climate system, Nature, 419, 215–223, 2002. Kistler, R., Kalnay, E., Collins, W., Saha, S., White, G., Woollen, J., Chelliah, M., Ebisuzaki, W., Kanamitsu, M., Kousky, V., van&nbsp;den Dool, H., Jenne, R., and Fiorino, M.: The NCEP-NCAR 50-Year Reanalysis: Monthly Means CD-ROM and Documentation, B. Am. Meteor. Soc., 82, 247–267, 2001. Lau, K.&nbsp;M. and Kim, K.&nbsp;M.: Observational relationships between aerosol and Asian monsoon rainfall, and circulation, Geophys. Res. Lett., 33, L21810, https://doi.org/10.1029/2006GL027546, 2006. Lau, K.&nbsp;M., Kim, M.&nbsp;K., and Kim, K.&nbsp;M.: Asian summer monsoon anomalies induced by aerosol direct forcing: the role of the Tibetan Plateau, Clim. Dynam., 26, 855–864, 2006. Lau, K.&nbsp;M., Ramanathan, V., Wu, G.&nbsp;X., Li, Z., Tsay, S.&nbsp;C., Hsu, C., Sikka, R., Holben, B., Lu, D., Tartari, G., Chin, M., Koudelova, P., Chen, H., Ma, Y., Huang, J., Taniguchi, K., and Zhang, R.: The Joint Aerosol-Monsoon Experiment, B. Am. Meteor. Soc., 89, 369–383, 2008. Lelieveld, J., Crutzen, P. J., Ramanathan, V., Andreae, M. O., Brenninkmeijer, C. A. M., Campos, T., Cass, G. R., Dickerson, R. R., Fischer, H., de Gouw, J. A., Hansel, A., Jefferson, A., Kley, D., de Laat, A. T. J., Lal, S., Lawrence, M. G., Lobert, J. M., Mayol-Bracero, O. L., Mitra, A. P., Novakov, T., Oltmans, S. J., Prather, K. A., Reiner, T., Rodhe, H., Scheeren, H. A., Sikka, D., and Williams, J.: The Indian Ocean Experiment: Widespread Air Pollution from South and Southeast Asia, Science, 291, 5506, https://doi.org/10.1126/science.1057103, 2001. Lin, S.&nbsp;J., Atlas, R., and Yeh, K.&nbsp;S.: Global Weather Prediction and High-End Computing at NASA, Comput. Sci. Eng., 6, 29–35, 2004. Liu, D., Wang, Z., Liu, Z., Winker, D., and Trepte, C.: A height resolved global view of dust aerosols from the first year CALIPSO lidar measurements, J. Geophys. Res., 113, D16214, https://doi.org/:10.1029/2007JD009776, 2008. Liu, Z., Omar, A.&nbsp;H., Hu, Y., Vaughan, M.&nbsp;A., and Winker, D.&nbsp;M.: CALIOP {A}lgorithm {T}heoretical {B}asis {D}ocument, {P}art&nbsp;3: {S}cene {C}lassification {A}lgorithms, NASA Langley Research Center, <a href="http://www-calipso.larc.nasa.gov/resources/pdfs/PC-SCI-202_Part3_v1.0.pdf">http://www-calipso.larc.nasa.gov/resources/pdfs/PC-SCI-202_Part3_v1.0.pdf</a>, last access: 17&nbsp;February&nbsp;2010, 2005. Liu, Z., Liu, D., Huang, J., Vaughan, M., Uno, I., Sugimoto, N., Kittaka, C., Trepte, C., Wang, Z., Hostetler, C., and Winker, D.: Airborne dust distributions over the Tibetan Plateau and surrounding areas derived from the first year of CALIPSO lidar observations, Atmos. Chem. Phys., 8, 5045–5060, https://doi.org/10.5194/acp-8-5045-2008, 2008. Meehl, G.&nbsp;A., Arblaster, J.&nbsp;M., and Collins, W.&nbsp;D.: Effects of Black Carbon Aerosols on the Indian Monsoon, J. Climate, 21, 2869–2882, 2008. Menon, S., Hansen, J., Nazarenko, L., and Luo, Y.: Climate effects of black carbon aerosols in China and India, Science, 297, 2250–2253, 2002. Omar, A.&nbsp;H., Winker, D., and Won, J.-G.: Aerosol models for the CALIPSO lidar inversion algorithms, Soc. Photo-Opt. Instru., 5240, 153–164, https://doi.org/10.1117/12.511067, 2004. Pease, P.&nbsp;P., Tchakerian, V.&nbsp;P., and Tindale, N.&nbsp;W.: Aerosols over the Arabian Sea: geochemistry and source areas for aeolian desert dust, J. Arid Environ., 39, 477–496, 1998. Ramanathan, V. and Carmichael, G.: Global and regional climate changes due to black carbon, Nat. Geosci., 1, 221–227, 2008. Ramanathan, V., Chung, C., Kim, D., Bettge, T., Buja, L., Kiehl, J.&nbsp;T., Washington, W.&nbsp;M., Fu, Q., Sikka, D.&nbsp;R., and Wild, M.: Atmospheric brown clouds: Impacts on South Asian climate and hydrological cycle, P. Natl. Acad. Sci., 102, 5326–5333, 2005. Ramanathan, V., Crutzen, P. J., Kiehl, J. T., and Rosenfeld, D.: Aerosols, Climate and the Hydrological Cycle, Science, 294, 2119–2124, https://doi.org/10.1126/science.1064034, 2001. Randles, C.&nbsp;A. and Ramaswamy, V.: Absorbing aerosols over Asia: A Geophysical Fluid Dynamics Laboratory general circulation model sensitivity study of model response to aerosol optical depth and aerosol absorption, J. Geophys. Res., 113, D21203, https://doi.org/10.1029/2008JD010140, 2008. Tafuro, A.&nbsp;M., Kinne, S., De Tomasi, F., and Perrone, M.&nbsp;R.: Annual cycle of aerosol direct radiative effect over southeast {I}taly and sensitivity studies, J. Geophys. Res., 112(D20), D20202, https://doi.org/10.1029/2006JD008265, 2007. Tindale, N.&nbsp;W. and Pease, P.&nbsp;P.: Aerosols over the Arabian Sea: Atmospheric transport pathways and concentrations of dust and sea salt, Deep-Sea Res. II, 46, 1577–1595, 1999. Wang, C., Kim, D., Ekman, A.&nbsp;M.&nbsp;L., Barth, M.&nbsp;C., and Rasch, P.&nbsp;J.: Impact of anthropogenic aerosols on Indian summer monsoon, Geophys. Res. Lett., 36, L21704, https://doi.org/10.1029/2009GL040114, 2009. Winker, D.&nbsp;M., Pelon, J., and McCormick, P.: The CALIPSO mission: {S}paceborne lidar for observation of aerosols and clouds, Soc. Photo-Opt. Instru., 4893, 1–11, 2003. Winker, D.&nbsp;M., Hostetler, C.&nbsp;A., Vaughan, M.&nbsp;A., and Omar, A.&nbsp;H.: CALIOP {A}lgorithm T}heoretical {B}asis {D}ocument, {P}art&nbsp;1: {CALIOP {I}nstrument, and {A}lgorithms {O}verview, NASA Langley Research Center, <a href="http://www-calipso.larc.nasa.gov/resources/pdfs/PC-SCI-202.Part1_v2-Overview.pdf">http://www-calipso.larc.nasa.gov/resources/pdfs/PC-SCI-202.Part1_v2-Overview.pdf</a>, last access: 17&nbsp;February&nbsp;2010, 2006. Xia, X. and Zong, X.: Shortwave versus longwave direct radiative forcing by Taklimakan dust aerosols, Geophys. Res. Lett., 36, L07803, https://doi.org/10.1029/2009GL037237, 2009. Xia, X., Wang, P., Wang, Y., Li, Z., Xin, J., Liu, J., and Chen, H.: Aerosol optical depth over the {T}ibetan {P}lateau and its relation to aerosols over the {T}aklimakan {D}esert, Geophys. Res. Lett., 35, L16804, https://doi.org/10.1029/2008GL034981, 2008.