肇庆持续低温天气的气候背景与前期海气异常特征

根据地面观测、NCEP/NCAR再分析等资料,采用合成分析方法,研究了肇庆持续低温天气的气候背景与前期海气异常特征.结果表明,极涡和中高纬长波脊偏强,南支槽较常年活跃,以及蒙古高压中心偏强是肇庆持续低温天气发生的气候背景.前期11月500 hPa极涡、亚洲中高纬平均脊和东亚槽都较常年偏强,前期7-10月赤道太平洋和北太平洋海温持续明显异常可作为肇庆持续低温天气预报的前兆信号.

Climate Background and Preceding Atmospheric and Marine Abnormality for Sustained Chilly Weather in Zhaoqing

Based on surface observations and NCEP/NCAR reanalysis, the climate background and preceding atmospheric and marine anomalies for sustained chilly weather in Zhaoqing are studied using the composite method. The result shows that anomalously strong polar vortexes and longwave high ridges at the mid- and higher-latitudes, a more-active-than-usual branch of the westerlies and an anomalously strong high over Mongolia are all the climate background for the weather. Precursory signals for the weather include an anomalously strong mean high ridge over the Asian mid- and higher-latitudes and large sustained abnormality of sea surface temperature in the equatorial Pacific and North Pacific in the preceding July to October.