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

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 normal) 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 normal (below normal) in whole province type is the leading type in the past 51 years. Different type has obviously different atmospheric circulation 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 appear; 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.