Temporal And Spatial Characteristics Of Extreme Precipitation Events In China And Projection

The inter-annual component of warm half year mean (May to October)precipitation, extreme precipitation, tropical cyclone (TC) or typhoon precipitation, isstudied by trend analysis for the period1961-2010. The precipitation in Chinaincreased significantly mainly due to the enhancement of the intensity of precipitation.The increasing of the intensity is larger than the frequency of precipitation. Theprecipitation extremes in China increased significantly mainly due to the enhancementof the frequency of precipitation extremes, although the intensity has no change in thepast50years. The TC precipitation in China decreased mainly due to the reduction ofthe times of TC precipitation. To the east of103°E, the percentage of extremeprecipitation in total precipitation is10%larger than that to the west. East Asiansummer monsoon causes such difference. The precipitation of the trend of extremerainfall in the trend of total rainfall is25-50%to the west of103°E. They (bothincreasing and decreasing trends) are much larger to the east of103°E, up to50-100%.Different from the most part of china, the trend of rainfall in the middle reach ofthe Yangtze River to the South-west of China, the middle and lower reaches of theYellow River and the Bohai rim region is decreasing. The trend of TC rainfallcontributes significantly to the trend of total rainfall in these regions. Above themiddle and lower reaches of the Yellow River and the Bohai rim region, there arecyclonic decreasing in the upper troposphere and anticyclonic decreasing in the lowertroposphere. The anomalous upper-level southerlies and low-level northerlies exist inthe eastern part of the cooling region. The upper-level cooling is associated with ananomalous meridional cell with descending motions in the lower reach of the Yangtze River to the South of China and low-level northerly winds over southeastern China,causing deficient rainfall over the middle and lower reaches of the Yellow River andthe Bohai rim region. There is an obvious warming center over the Tibetan Plateau.Corresponding to the upper-level cooling, the atmospheric thickness is thinned in theupper troposphere. Thus the geopotential height lowers in the upper troposphere.Underneath the upper-level cooling, the geopotential height rises. This can beexplained by the thermal wind relation in terms of the hydrostatic balance.Accompanied with the upper-level cooling, the cold dense air in the upper troposphereis taken to the Southwest of China, causing deficient rainfall over this region.Evaluation and projection of extreme rainfall over China are carried out with33model data from CMIP5. Used for the prediction of extreme precipitation, with atleast41years of history data for prediction can achieve better prediction results. Interannual variation of extreme precipitation in the lower reach of Yangtze River isinfluenced significantly by high temperature of Yangtze River Basin and offshore SSTforcing in summer. Meanwhile, it is also influenced by the equatorial eastern Pacificin the previous spring and the sea ice extent of Arctic in the previous autumn. Interdecadal variation is effected by the equatorial eastern Pacific in the previous autumn,the north Pacific in the previous winter and the temperature of the Tibetan Plateau.The predictors of inter annual variation of extreme precipitation in the East of Chinaare SOI and NPO in the previous winter, the equatorial eastern Pacific in the previousautumn and Japan Current in the previous winter. Inter decadal variation is effected bythe sea ice extent of Arctic in the previous winter and the temperature of the TibetanPlateau.