Abstract:

 Based on temperature data of 82 stations in Northwest China and NCEP reanalysis data of the monthly mean grid OLR，the relationship between air temperature in Arid region of Northwest China and OLR over the Qinghai － Tibet plateau was analyzed by using EOF，synthesis and correlation analysis methods． The main conclusions are as follows: ( 1) The high value center of the first mode of OLR concentrated in the northern Tibet Plateau，which faced west in winter and moved to the east in spring，in summer located in west section of the Tanghla mountain． The temperature in January correlated positively with OLR at the same time，and they had the same decadal and interannual change tendency，but presented opposite correlation with the OLR lagged for six months ( July of last year) ．The temperature in July and the same time OLR presented opposite decadal tendency，but the opposite interannual trend was not remarkable，and correlated positively with the OLR lagged for seven months ( December of last year) and negatively with OLR lagged for11 months ( August of last year) ． Namely，when the OLR over Qinghai － Tibet plain in July was abnormally large ( small) ，the temperature in January of next year in arid region was abnormally low ( high) ． When OLR over Qinghai － Tibet Plain in August and December
was abnormally large ( small) ，the temperature in July of next year would be abnormally high ( low) ; ( 2) The low value center of OLR over Qinghai － Tibet plateau also has some relations with temperature in arid region of Northwest China，namely，the temperature in January correlated positively with OLR at the same time and negatively with OLR lagged for 17 months，the temperature in July correlated positively with OLR lagged for 17 months and negatively with OLR lagged for 12 months．

Key words: OLR, EOF, air temperature, Qinghai － Tibet Plateau, Northwest China, arid area

摘要：

利用中国西北地区82 站地面气温资料和NCEP 再分析月平均地气系统射出长波辐射( OLR)资料，采用EOF、合成分析、相关分析方法，分析了干旱区气温与青藏高原OLR 的关系，结果表明: ( 1)青藏高原OLR 第一模态的高值区相对集中在藏北高原，冬季偏西，春季向东移动，夏季最东在唐古拉山西段。OLR 异常影响干旱区的气温。其中，1月OLR 与同期气温正相关，有相同的年代际和年际变化趋势，滞后6 个月( 上年7 月) 负相关; 7 月OLR 与同期的气温年代际趋势是相反的，年际变化呈不显著的反相关，滞后7 个月( 上年12 月) 正相关、滞后11 个月( 上年8 月) 负相关，都有显著相关区。即当青藏高原夏季7 月OLR 异常偏大( 小) 时，对应干旱区次年冬季1 月气温异常偏低( 高) 。青藏高原8 月和12 月OLR 异常偏大( 小) 时，对应干旱区次年夏季7 月气温异常偏高( 低) ; ( 2) 青藏高原OLR 低值中心与干旱区气温的关系: 1 月气温与同期高原OLR 正相关、与前两年8 月负相关; 7月气温与前一年2 月高原OLR 正相关、与前一年8 月负相关。

关键词: OLR, 气温, EOF 分析, 青藏高原, 中国西北, 干旱区