HR: 0800h
AN: B41C-0218    [Abstracts]
TI: Analyses on the factors influencing stable isotopes in precipitation in the southwestern China
AU: * Zhang, X
EM: zhang@geo.utexas.edu
AF: Hunan Normal University, College of Resources and Environment, Changsha, Hunan, 410081 China
AU: Yang, Z
EM: liang@mail.utexas.edu
AF: University of Texas at Austin, Department of Geological Sciences, 1 University Station #C1100, Austin, TX 78712 United States
AB: This study analyzes the relationships of stable isotopes in precipitation with temperature, pressure and humidity at different altitudes and the factors influencing stable isotopes in precipitation in the southwestern China. There are marked negative correlations of the delta-18O in precipitation with sampling precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations under synoptic scales; the marked negative correlations occur between the delta-18O in precipitation and the daily mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa, which is different from the temperature effect in mid- and high-latitude inland areas. In addition, the notable positive correlations between the delta-18O in precipitation and the dew-point deficit at different altitudes were found at the three stations. The annual mean delta-18O displays the negative correlations not only with annual precipitation, to a certain extent, but also with annual mean temperature at 500 hPa markedly. It can be deduced that, in the years with abnormally strong summer monsoon, more warm-wet air from low-latitude oceans is transported northward along the vapor channel located in the southwestern China and forms abnormally strong rainfall on the way. Simultaneously, the abnormally strong condensation process produced will release more condensed latent heat into the atmosphere, therefore, the atmospheric temperature rises during rainfall, but the delta-18O in precipitation reduces with the stronger rainfall. On the contrary, in the years with abnormally weak summer monsoon, the precipitation and the atmospheric temperature during rainfall decrease abnormally, but the delta-18O in precipitation increases.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1655 Water cycles (1836)
DE: 1854 Precipitation (3354)
DE: 3314 Convective processes
DE: 4904 Atmospheric transport and circulation
SC: Biogeosciences [B]
MN: Fall Meeting 2005