2006年夏季川渝地区伏旱与低频大气热源的关系  

The relationship between the low-frequency oscillation atmospheric heating source/sink and the drought in the Sichuan-Chongqing region in summer of 2006

作　　者：岑思弦[1] 巩远发[2] 秦宁生[1] 赖欣[2] 王霄[3] 黄先伦 

机构地区：[1]中国气象局成都高原气象研究所,成都610072 [2]成都信息工程学院高原大气与环境研究中心,成都610225 [3]河南省气象科技服务中心,郑州450003 [4]阳江市气象局,广东阳江529500

出　　处：《气象学报》2011年第6期1009-1019,共11页Acta Meteorologica Sinica

基　　金：国家自然科学基金资助项目(40675036;40633018);高原气象开放实验室基金课题(LPM2009019);四川省气象局青年基金课题"亚洲季风区大气热源汇的变化与川渝旱涝的研究"

摘　　要：利用NCEP/NCAR再分析资料和中国地面观测站的逐日降水资料,研究了2006年夏季中国川渝地区的伏旱与亚洲地区大气低频振荡的联系。结果表明,2006年夏季中国川渝地区降水低频振荡的主要周期约为60d;在川渝严重干旱期的7月下旬至8月上旬,经向上由于川渝地区上空低频热汇、广西和海南及其以西地区上空低频热源的影响,在15°—40°N地区上空形成一个低频经圈环流,该环流圈的下沉支刚好位于川渝地区上空;纬向上在中国台湾及其附近地区上空低频热汇和其以西地区上空低频热源的共同影响下,在105°—130°E地区上空形成的低频纬圈环流以及80°—105°E地区上空出现的次级低频纬圈环流,加强了中国川渝以南地区上空的低频上升气流,这样进一步加强了经向上15°—40°N地区的低频经圈环流。在这个低频经圈环流的作用下,一方面加强了中国川渝地区上空的低频下沉气流,另一方面加强了川渝地区低层的低频辐散气流,结果导致中国川渝地区发生了严重的伏旱。In the summer of 2006, the severe drought occurred in the SichuawChongqing region. In order to investigate the cause, using the NCEP/NCAR reanalysis data and the observed daily rainfall from the gauge stations, the relationship of the low-frequency oscillation （LFO） atmospheric heating source/sink with the severe drought in the Sichuan-Chongqing region in the summer of 2006 has been studied. The results show that the summer rainfall in 2006 over the Sichuan-Chongqing region was dominated by the about 60 day oscillatiom during the period of the severe drought in the Sichuan-Chongqing region from late July to early August, longitudinally, due to the influences of the LFO heat sink over the Sichuan-Chongqing region and the LFO heat source over the Guangxi, Hainan and west of the region, there was a low-frequency meridional circulation cell formed over the region between the 15~N and 40~N, whose downward branch of the circulation cell is just located over the Sichuan- Chongqing region; latitudinally, under the joint influences of the LFO heat sink over the Taiwan and its surrounding areas and the LFO heat source west of the Taiwan and its surrounding areas, the low frequency zonal circulation cell was formed over the region between 105~E and 130~E and another secondary low frequency zonal circulation cell emergenced over the region between 85~E and 105~E, which strengthened the low frequency upward motion over the Guangxi and Hainan and west of the region, and thus further strengthened the low-frequency meridional circulation that was formed over the region between the 15~N and 40~N. As a result, on the one hand, it strengthened the low-frequency downward flow over the Sichuan-Chongqing region and, on the other hand, also strengthened the low-frequency divergence of the low-level flow over the Sichuan-Chongqing region. The difference of zonal distribution of the LFO further strengthened the downward flow over the Sichuan-Chongqing region, which might be the important cause why over the Sichuan-Chongqing region th

关 键 词：低频振荡 大气热源(热汇) 川渝地区 伏旱 

分 类 号：P463.1[天文地球—大气科学及气象学]