短时间尺度下降水中稳定同位素变化特征及其意义

根据2007年11月－2008年3月广州大气降水中稳定同位素和气象资料，探讨了短时间尺度下降水中稳定同位素变化规律。采样期间所得到的降水中稳定同位素与气温在天气尺度下呈现出显著的正相关关系，可能与2008年初南方发生严重冰雪冻雨灾害期间特殊的大气环流形势、水汽输送等因素有关。在单次连续降水过程中，降水中稳定同位素变化特征主要有两类，一类是随着降水的持续，降水中稳定同位素逐渐降低，另一类则是降水中稳定同位素表现出V型结构特征，且降水中过量氘（d）的变化与同位素变化趋势类似，这些不同类型的同位素组分变化趋势可能跟水汽来源、锋面活动、雨滴下落过程中所受到的蒸发分馏等有关。

Isotopic Variations of Precipitation in Guangzhou and Its Implications at Short - Time Scales

Based on the stable isotope (D, 18O) in precipitation selected at Guangzhou from November 2007 to March 2008 and the meteorological data, the isotopic variations of precipitation at short-time scales was analyzed. On the daily time-scale, there is a significantly positive relation between the 18O and D in precipitation with the daily air temperature, and this could be correlated to the occurrence of the severe cold surge, ice-snow and frozen disasters in the south China at the beginning of 2008. We also find that there are mainly two kinds of the isotopic changing tendency during one single precipitation process. One kind is an obvious declining pattern during the continuance of the rainfall process, and another kind is a V pattern during the rainfall process, and it is quite similar with the variation of its d-excess. We concluded primarily that these different kinds of isotopic variation patterns were probably correlated to the water sources, frontal activities, evaporation, dephlegmation processes and etc.