选用1961-2019年中国京津冀地区气象观测站点日最低气温、NOAA月海表温度和NCEP/NCAR月500 hPa高度场,统计分析该地区冬季强冷空气日数变化特征及其与海表温度的关系,及Niño3.4区海温影响强冷空气的太平洋-北美型(Pacific North American pattern,PNA)遥相关机制.结果表明:京津冀地区冬季单站强冷空气年均发生日数为0.0～8.7 d,空间分布为西北向东南递减.京津冀地区冬季强冷空气日数同前期夏季、秋季和同期冬季海温的显著正相关区主要位于赤道中东太平洋,而西风漂流区和北大西洋东北部显著负相关区出现在前期秋季和同期冬季,赤道印度洋显著正相关仅在同期出现.京津冀地区冬季强冷空气日数异常受乌拉尔山高压脊、贝加尔湖低压、东亚中低纬度异常高压和东亚大槽等500 hPa高度场变化影响.同时,Nino3.4区海温异常通过PNA遥相关模式影响高度场变化,间接影响该地区的强冷空气日数.
Study on the relationship between the number of strong cold air days and the interannual variation of sea surface temperature anomalies from 1961 to 2019 in Beijing-Tianjin-Hebei region of China
Utilizing meteorological observatory data of daily minimum temperature from 1961 to 2019 in Beijing-Tianjin-Hebei region of China,along with NOAA's monthly sea surface temperature and NCEP/NCAR's monthly 500 hPa geopotential height field,this study employs physical statistical methods to analyze the variation character-istics of the number of strong cold air days during winter in the region and its relation to sea surface temperatures.This study also explains the mechanism behind the Pacific North American(PNA)teleconnection pattern influ-enced by sea temperatures in the Nino 3.4 region.The results indicate that the average annual number of strong cold air days in Beijing-Tianjin-Hebei region varies between 0.0 to 8.7 days,with a spatial distribution decreasing from northwest to southeast.Interannually,the number of strong cold air days during winter in Beijing-Tianjin-He-bei significantly correlating with the preceding summer,autumn,and concurrent winter sea temperatures are mainly in the central and eastern equatorial Pacific.Significant negative correlation areas in the westerly jet region and northeastern North Atlantic appear in the preceding autumn and concurrent winter.A pronounced positive correla-tion with the equatorial Indian Ocean is maintained concurrently.Anomalies in the winter strong cold air days in Beijing-Tianjin-Hebei region are influenced by variations of 500 hPa geopotential height field features such as the Ural Mountain high-pressure ridge,Baikal Lake low-pressure,the anomalous high-pressure over mid-low latitudes of East Asia,and the East Asian trough.Concurrently,sea temperature anomalies in the Nino 3.4 region affect the variation of height field through the PNA teleconnection pattern,indirectly influencing the number of strong cold air days in the region.
万方数据
