青藏高原热力状况与四川盆地汛期降水的联系

THE RELATIONSHIP BETWEEN THERMAL REGIME IN QINGHAI XIZANG PLATEAU AND PRECIPITATION IN SICHUAN BASIN DURING FLOOD SEASON

应用高原积雪日数和高原气温、四川盆地逐月降水量资料，应用ＳＶＤ等方法，探讨高原热力状况分布异常与四川盆地汛期降水分布的联系。分析结果表明，高原积雪日数场分布特征是以巴颜喀拉山和念青唐古拉山为中心。该区域冬季积雪日数异常与川中盆地汛期干旱有相当好的联系。春季青藏高原北部和祁连山的温度场的大范围异常则与川西的洪涝和川东的干旱均有较好的相关，均可作为四川降水长期预报综合考虑的重要参考因子。一般而言，积雪日数对降水的影响时间长于温度，可能与积雪融化和雪水向土壤的渗透等产生较长时间的滞后效应有关，因而对大气环流和四川降水的影响时段较长。其中与８月份降水的相关超过整个汛期。

Based on the data set of the perpetual snow duration and temperature in the Plat eau and precipitation in Sichaun Basin. The relationship between the thermal regime distribution in the Qinghai Xizang Plateau and the precipitation in the Sichuan Basin during the flood season was investigated using the Singular Value Decomposition method. The results are as follows: the distribution character of the Plateau perpetual snow duration is that the centers are located in the Bayanhar mountain and Nyainqêtanglha mo untain. The anomaly in these area in winter related to the precipitation in the middle part of Sichuan Basin during flood season. There is close relationship between the large extent anomalies of the temperature in Qaidam Basin and Qilian mountain and the flooding in the west part and the drought in the east part of Sichuan Basin. The prepetual snow duration and the temperature in the Plateau should be consider as the factor of the long forecas ting for the precipitation in Sichuan. In general,the period for prepetual snow bring atmospheric circulation and precipitation into effect is longer than the temperature, because of snow melting and water into the soil need long time. The August precipitation in Sichuan Basin obviously are affeced by the snow and temperature in the Qinghai Xizang Plateau.