Supported jointly by the National Natural Science Foundation of China under Grant No.40675025;the Jiangsu Key Laboratory of Meteorological Disaster under Grant No.KLME060101;the National Key Technology R&D Program under Grant No.2007BAC29B02.
The NCEP/NCAR reanalysis data have been employed to diagnose variations of the zonal mean flow in boreal summer. Two leading EOF modes are found to dominate the spatial and temporal changes of the summertime zonal mea...