Comparative Analysis on Two Persistent Low-temperature Event in Zhaoqing

作者：Peng Duan · 发表于：Guangdong Meteorology · 年份：2012 · 研究领域：Environmental and Agricultural Sciences、Environmental Changes in China、Remote Sensing and Land Use

The conventional meteorological observation and the NCEP/NCAR reanalysis data are employed to study two persistent low temperature events in Zhaoqing at the beginning of 2008(case 2008) and 2011(case 2011),from the perspective of the weather characteristics,the large-scale circulation and the impact of La Nina event.The results show that in case 2008,the main chilling injury weather is the cold and rainy weather,while in case 2011,is low temperature,frost and freezing.The two cases have common circulation features of abnormally stronger Siberia cold high,as well as the mid-high latitude troughs and ridges at 500 hPa.Differences are also obvious.In case 2008,the active southern branch trough and strong subtropical high brought the warm and moist airstream northward,converging with the continuously southward cold air in south China,which resulted in persistent low temperature and rainy weather.In case 2011,the East Asian trough located more eastward,the subtropical high was weaker anomalously,the zonal circulation dominated the middle-low latitudes,warm and humid air was not strong enough at 850 hPa,and the Mongolia high and Aleutian low was abnormally stronger.All these are in favor of the enhancement the east Asian winter monsoon with less precipitation.The results also show that the moderate to strong La Nina event with eastern pattern might indicate the longer duration of cold weather in Zhaoqing at the beginning of the year when La Nina event comes to an end.