The relationships between the global satellite-observed outgoing longwave radiation and the rainfall over China in summer and winter

Abstract

The relationships between the flux of outgoing longwave radiation (OLR) and the rainfall over China are examined by using monthly OLR data from NOAA polar-orbiting satellites and China 160-station precipitation observations in summers and winters, respectively, for 20-year period from 1980 to 1999. The singular value decomposition (SVD) analysis is carried out for the two fields: (1) The first two principal rainfall modes of China are related with the south–north oscillation occurred over the western Pacific and East Asia for the summers. One of them is wetter over the south-eastern China and the other is wetter to the south of Yellow River. (2) The first rainfall mode over China, which exhibits most parts of China wetter, is closely associated with the east–west oscillation between the equatorial central-eastern Pacific and the western Pacific for the winters. (3) The OLR practical anomaly distributions indicate that the intensely convective activities dominate the China rainfall areas during the summers of 1997, 1998 and 1999. The OLR anomalies also clearly showed extreme drought events occurred over the north-eastern China in the summers of 1997 and 1999.