大气环流指数和海温对呼伦贝尔地区年降水预测的指示意义

文章对近50a（1961—2010年）内蒙古呼伦贝尔地区的年、汛期和冬春季降水量和降水距平百分率（R%）作了统计,发现年R%和冬春季R%呈上升趋势,汛期R%略呈下降趋势;通过对年R%与大气环流指数、海温的相关分析发现：前期副热带高压（副高）、北半球极涡、大西洋欧洲环流C型、西藏高原位势高度和印缅槽（南支槽）强度指数等均与年R%密切相关,当北半球极涡收缩、强度减弱,副高扩张、强度加强,西藏高原位势高度偏高,南支槽减弱时,有利于来年呼伦贝尔地区降水,否则,相反。此外,前一年夏季北印度洋海域和赤道东太平洋海域海温对呼伦贝尔地区来年降水有显著影响,这两块海区的海温和上述环流指数可考虑作为呼伦贝尔地区年降水的预测信号使用。

Study on Indicating Functions of the Atmospheric Circulation Indices and the Sea Surface Temperature for Annual Precipitation Forecast of Hulun Buir Region

The annual,rain-season and winter-spring precipitation and precipitation anomaly in percentage(R%) of Hulun Buir City(Region) in Inner Mongolia,China during the past 50 years(from 1961 to 2010) were calculated in this study.From the result of the calculation,it has been found that the annual and winter-spring R% display a significant increase trend.In opposite,the rain-season R%,however,shows a slight decrease trend during the 50-year period.Besides,it has been found in outcomes of the correlation analyses between the R% and all atmospheric circulation indices that the precious subtropical high(SH),North Polar vortex(NPV),Atlantic and Europe pattern C(Pattern-C),geopotential high of the Tibetan Plateau(GH-TP) and the India-Burma trough(IBT,also called South branch trough) have close connections with the R%.That indicates when the NPV is small and weak,the atmospheric circulation over the Atlantic and European region exhibits the Pattern-C,the GH-TP changes to higher than normal,the IBT is weak,the SH extends to north-westward and becomes strong in the previous time,all of these will be very helpful for next year precipitation in the Hulun Buir Region,and vise verse.In addition,two significant regions(the northern India Ocean and the Equator nearby region over the East Pacific Ocean) in correlation field between the R% and the sea surface temperature anomaly(SSTA) have been found to be very close to the next year precipitation of the Hulun Buir.Mean sea surface temperature of the two regions and the atmospheric circulation indices mentioned above may provide significant predicting signals to future annual precipitation forecast for the Region.