摘要
利用徐闻站和湛江站1960—2015年4—10月的降水资料和NCEP/NCAR再分析资料,根据1倍标准差的原则对前、后汛期累计降水、无降水总日数和最长无降水日数3个变量进行偏大(小)年份的极端值判断,并在此基础上根据选出来的干旱年对500 h Pa位势高度、850 h Pa风场和水汽输送垂直积分异常分布进行合成分析。结果表明:徐闻站和湛江站的无降水日数在前后汛期变化趋势比较一致,但是最长无降水日数在前后汛期趋势显著不同;湛江站和徐闻站前后汛期干旱异常年对应的副高异常有着明显正异常关系,副高的正异常对于雷州半岛前后汛期干旱有着加强的作用;反气旋环流与反气旋式水汽环流控制下对湛江站前汛期和徐闻站后汛期干旱产生影响,而异常偏弱的季风环流和沿季风路径的水汽输送影响湛江站后汛期干旱,水汽输送辐散对徐闻站前汛期干旱有影响。
With the rainfall data of observation stations in Xuwen and Zhanjiang and NCEP/NCAR reanalysis from April to October in 1960-2015 and following the principle of one time standard deviation, we determine the anomalously large （small） extremes of three variables of accumulated rainfall, total number of rain-free days and maximum number of consecutive rain-free days. Then, for the drought years chosen on the basis of that, we perform a composite analysis of anomalous distribution of 500 hPa geopotential height, 850 hPa wind field and vertical integration of water vapor transport. The result is shown as follows. Between the two stations, the total number of rain-free days is quite consistent between the two flooding seasons while the maximum number of consecutive rain-free days is much different between them. The subtropical high anomalies for anomalously dry years in both seasons are much positive. The positive anomalies of the subtropical high play an enhancing role in the drought of Leizhou Peninsula in both seasons. Under the control of anti- cyclonic circulation and anti-cyclonic water vapor circulation, the drought in the Zhanjiang station during the annually first flooding season and the Xuwen station during the annually second flooding season is affected. Anomalously weaker monsoon circulation and water vapor transported along the monsoon route affect the drought of Zhanjiang station in the annually second flooding season while water vapor divergence affects the drought of Xuwen station in the annually first flooding season.
出处
《广东气象》
2017年第3期22-26,共5页
Guangdong Meteorology
关键词
气候学
干旱
前汛期
后汛期
雷州半岛
climatology
drought
annually first flooding season
annually second flooding season
Leizhou Peninsula
