西藏高原夏季旱涝年OLR分布差异

OLR DISTRIBUTION IN SUMMER IN DRYNESS/WETNESS YEARS OVER TIBETAN PLATEAU

根据美国NOAA卫星观测得到的射出长波辐射资料 (OutgoingLongwaveRadiation ,简称OLR) ,分析了西藏高原及其附近地区各月的辐射气候特征 ,指出 :高原冬、春季节OLR主要反映了高原下垫面温度的季节变化 ,高原夏季为雨季 ,OLR与降水之间存在较好的负相关。印度季风爆发前后的OLR演变特征反映出中、低纬大气环流调整对高原雨季形成及降水分布的影响。旱涝年OLR合成分析表明 :高原夏季降水与赤道印度洋反Walker环流强弱、印度季风槽、副热带高压及西太平洋暖池区对流强度。

Based on the OLR data observed by NOAA satellite,the climatic features of the radiation over the Tibetan Plateau and adjacent areas are investigated.The main results are as follows:the Plateau acts as the heat sink of the surface heating fields in winter and OLR is low ;the Plateau rainfall mainly concentrates in summer and OLR is also low.There exists significant negative correlation between OLR over the Plateau and Plateau precipitation in summer;the change of OLR during the onset of Indian Monsoon reflects the adjustment of the Northern Hemisphere general circulation as well as the spatial and temporal pattern of thermal conditions over the Plateau during wet season.Composite India Ocean OLR anomalies patterns for five wet(dry) years over the Tibetan plateau in summer are studied. It is found that convection on the west and east of the Indian Ocean is abnormal obviously.Correlation analysis shows that OLR over the Bay of Bengal during spring has better negative relationship with rain over the Plateau in summer.