贵州省2011年与2013年7—8月干旱对比分析及对农业的影响

Comparative Analysis of Drought in Guizhou from July to August between the Year of 2011 and 2013 and the Effect on Agriculture

利用NCEP再分析月平均资料、全省87站降水、气温、MCI监测资料、向外长波辐射OLR(Outgo inglongw ave rad iation)资料,分析了2011年和2013年夏季7到8月间干旱实况和环流的异常特征。结果表明,2011年和2013年降水偏少,降雨量排位为1981年以来同期第一和第二,气温偏高,2013年7到8月平均气温为1981年以来最高的1年达到25.4℃。2011年和2013年副高和南压高压偏强,贵州等地及其水汽来源区域的对流活动都受到抑制,由南向北的水汽输送较差,来自北方的冷空气偏弱,西北气流不明显,贵州、四川一带没有明显的冷暖空气交汇带,导致降水偏少、气温偏高,最终形成了2011年和2013的干旱。赤道中东太平洋海表面温度大范围持续变冷(暖)的现象可引起大气环流的异常相应,可将ENSO事件作为次年预测贵州夏季干旱与否的重要因子。建议在贵州夏季干旱易发区域建设农业生产对策研究试验基地,指导农民改进农业种植结构,加大人工增雨力度应对夏旱。

Based on the NCEP /NCAR reanalysis monthly mean data, the 87 stations＇ precipitation, temperature, MCI monitoring data in Guizhou and the OLR（outgoing long wave radiation） data, the July-August drought situation and the anomalous character of atmospheric circulation in the summer of 2011 and 2013 have been analyzed. The results show that both 2011 and 2013 have low rainfall and high temperatures in July and August,the precipitations are the least one and next to the least one,and the July-August mean temperature of 25.4 ℃ ranks highest ever since 1981. The Western Pacific subtropical high and South Asia high are both relatively strong so that the atmospheric convection of the moisture sources area and Guizhou are restrained. Because of poor water vapor transport from south to north and weak north cold air, there is no obvious confluence of cold and warm air belt in Guizhou-Sichuan region,therefore the temperature is on the high side and the precipitation is on the low side. Eventually the drought appears in 2011 and2013. Eastern equatorial Pacific sea surface temperatures continued large-scale cold（warm） phenomenon can cause atmospheric circulation anomalies corresponding. It is suggested that in summer drought prone areas in Guizhou, constructing agricultural production countermeasures to cope with summer drought testing base, guiding farmers to improve agricultural planting structure, increasing artificial rainfall to deal with summer drought.