Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 25 Precipitation: Measurement, Climatology, Remote Sensing, and Modeling (EGU Session 2009) 2010 10.5194/adgeo-25-23-2010 http://www.adv-geosci.net/25/23/2010/ http://www.adv-geosci.net/25/23/2010/adgeo-25-23-2010.html http://www.adv-geosci.net/25/23/2010/adgeo-25-23-2010.pdf 23 28 2010-03-08 Seasonal changes in diurnal rainfall cycle over and around the Indochina Peninsula observed by TRMM-PR H. G. Takahashi hiroshi3@tmu.ac.jp Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kanagawa, Japan Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University (TMU), Tokyo, Japan This study used TRMM-PR data to examine seasonal changes in rainfall characteristics over the Indochina Peninsula, with a focus on the diurnal rainfall cycle. No distinct seasonal changes in the phases of diurnal variations of rainfall were found, even though low-level wind fields changed largely with the seasonal march. Regions with an afternoon maximum received large amounts of rainfall during the pre-monsoon season, whereas regions with a nocturnal or morning rainfall maximum received little rainfall during the pre-monsoon season. This result suggests that the difference in diurnal rainfall variations may be associated with the regional differences in seasonal march of monsoon rainfall over and around the Indochina Peninsula, through the different mechanism between evening and morning rainfalls. Fujita, M., Sasaki, T., and Kimura, F.: A dramatic daytime decrease in water vapor over coastal Thailand, SOLA, 2, 49–52, 2006. Hirose, M. and Nakamura, K.: Spatial and diurnal variation of precipitation systems over Asia observed by the TRMM Precipitation Radar, J. Geophys. Res., 110, D05106, doi:10.1029/2004JD004815, 2005. Iguchi, T., Kozu, T., Meneghini, R., Awaka, J., and Okamoto, K.: Rain-profiling algorithm for the TRMM Precipitation Radar, J. Appl. Meteorol., 39, 2038–2052, 2000. Kodama, Y., Ohta, A., Katsumata, M., Mori, S., Satoh, S., and Ueda, H.: Seasonal transition of predominant precipitation type and lightning activity over tropical monsoon areas derived from TRMM observations, Geophys. Res. Lett, 32, doi:10.1029/2005GL022986, 2005. Matsumoto, J.: Seasonal transition of summer rainy season over indochina and adjacent monsoon region, Adv. Atmos. Sci., 14, 231–245, 1997. Murakami, M.: Analysis of the deep convective activity over the western Pacific and Southeast Asia. Part I: Diurnal variation, Journal of the Meteorological Society of Japan, 61, 60–76, 1983. Nitta, T. and Sekine, S.: Diurnal variation of convective activity over the tropical western Pacific, Journal of the Meteorological Society of Japan, 72, 627–641, 1994. Onogi, K. et~al.: The JRA-25 Reanalysis, Journal of the Meteorological Society of Japan, 85, 369–432, 2007. Satomura, T.: Diurnal variation of precipitation over the Indo-China Peninsula: Two-dimensional numerical simulation, Journal of the Meteorological Society of Japan, 78, 461–475, 2000. Takahashi, H. and Yasunari, T.: A climatological monsoon break in rainfall over Indochina -A singularity in the seasonal march of the Asian summer monsoon-, J. Climate, 19, 1545–1556, 2006. Takahashi, H. and Yasunari, T.: Decreasing trend in rainfall over Indochina during the late summer monsoon: Impact of tropical cyclones, Journal of the Meteorological Society of Japan, 86, 429–438, 2008. Takahashi, H., Yoshikane, T., Hara, M., and Yasunari, T.: High-resolution regional climate simulations of the long-term decrease in September rainfall over Indochina, Atmos. Sci. Lett., 10(1), 14–18, doi:10.1002/asl.203, 2009. Takahashi, H., Fujinami, H., Yasunari, T., and Matsumoto, J.: Diurnal rainfall pattern observed by TRMM-PR around the Indochina Peninsula, J. Geophys. Res., 115, \doi10.1029/2009JD012155, 2010a. Takahashi, H., Yoshikane, T., Hara, M., Takata, K., and Yasunari, T.: High-resolution modelling of the potential impact of land-surface conditions on regional climate over Indochina associated with the diurnal precipitation cycle, Int. J. Climatol., doi:10.1002/joc.2119, 2010b.