Analysis Of The Circulation Variations And The Summer Rainfall In Shandong Province

By using monthly averaged NCEP/NCAR reanalysis data of the atmospheric circulation and the data of summer precipitation in 17 meteorological stations in Shandong province from 1961 to 1998, spatial and temporal characteristics of summer precipitation are analyzed, and the relations between the atmospheric circulation and rainfall patterns are discussed. The basic precipitation pattern is in phase with each part of the whole province. The summer rainfall is degressive from southeast to northwest of the province. The difference of rainfall between the south and the north is obvious, and the oscillation period is about 3.8-9 year.Based on the drought and flood that had been definded, The relation between the atmospheric circulation and rainfall patterns during summer in Shandong province is discussed. The resultes show tha; in drought/flood years prominent circulation anonmalies occur over Northern Hemisphere. The trough in East Asia , Ural Araea Blocking and Western North Pacific Subtropical High are very important systems influencing the summer precipiation .The difference of physical features and high jets beteen drouht and flood show that tropical and subtropical systems are effecting the summer precipiation .The circulation anomalies in Europe-Asia from high latitudes to low latitudes appears to be the EU teleconnection pattern of the general circulation.Studied the pre~atmospheric circulations find that Tropical convection activity are important system influencing the summer precipitation. In the wet-years they are strong .Through Hadley Cell and Wealk Cell the energy is transfer to middle latitudes and high latitudes. The PNA, EU teleconnection pattern in winter may be a important factor which effected the the summer precipitation in Shandong province.