近51a福建早春不同低温阴雨分布型的环流特征及成因

The atmospheric circulation characteristics and causes about different types of cold and rainy weather during early spring in Fujian province in the past 51 years

利用1960—2010年福建省早稻播种育秧期平均气温、日照资料及NCEP/NCAR再分析资料,运用EOF和相关合成等方法,分析近51 a福建省早稻播种育秧期低温阴雨日数分布类型与各类低温阴雨日数分布类型同期大气环流背景场及海温分布特征,并探讨其成因。结果表明:福建省低温阴雨日数空间分布主要为全省一致、南北相异两种类型,其中全省一致偏多(少)型为福建省低温阴雨空间分布主要类型。不同的低温阴雨型具有明显不同的环流特征,当欧亚大陆中高纬度为两槽一脊形势,槽脊强度强,易发全省一致偏多型低温阴雨,其强度弱则易发北多南少型低温阴雨;当欧亚大陆中高纬度为两槽两脊形势,则易发北少南多型低温阴雨,当欧亚大陆中高纬度环流平直,则低温阴雨一致偏少。全省一致偏(多)少型、北多南少型与海温异常关系不大;前冬赤道中部海温异常偏暖,易发北少南多型低温阴雨。福建低温阴雨天气的发生,需要适当强度的冷空气和稳定的水汽通道。

Using the daily average temperature and sunshine at observatories in Fujian province and the NCEP/NCAR reanalysis data from 1960 to 2010, distribution types, atmospheric circulation and SST field characteristics of the cold and rainy weather during rice seeding period in early spring in Fujian are studied and the causes are investigated with the methods of empirical orthogonal function （EOF） and composite analysis etc. The results show that there are mainly two anomalous distribution types： one is above normal （below normaD in whole province, the other is above normal （below normal） in the northern province and below normal （above normal） in the southern province. The above nor- mal （below normal） in whole province type is/he leading type in the past 51 years. Different type has obviously different atmospheric circula- tion characteristics. When there are two troughs and one ridge over the mid-and high- latitudes area of Asia and Europe, the above normal in whole province type is easy to appear if the troughs and ridge are all strong or the above normal in the northern province and below normal in the southern province type is easy to appear if the troughs and ridge are weaker, When there are two troughs and two ridge over the middle and high latitude area of Asia and Europe, the below normal in the northern province and above normal in the southern province type is easy to ap- pear; when the zonal circulation over middle and high latitude area of Asia and Europe is considered as the main characteristics, the below normal in whole province type is easy to appear. The above normal （below normal） in whole province type, the above normal in the northern province and below normal in the southern province type have little relationship with the abnormal SST. The below normal in the northern province and above normal in the southern province type is easy to appear if the SST in the area of the middle equator in preceding winter is obviously higher than normal. The appearance of cold and rainy weather needs proper cold air and stable transferring of water vapor