A Study On Some Problems Of The Climate Change Of Global Land Precipitation For December-February During 1948-2001

Based on global land monthly precipitation dataset PREC/L during the period of 1948-2001, NCEP/NCAR reanalyzed monthly mean wind data and global monthly SST grid data edited by British Meteorological Bureau .the flood/drought and the secular trend variation of precipitation of global, the Northern hemisphere (NH) ,the Southern hemisphere(SH), Eurasia, Africa, Australia, North America, South America and Antarctica in December-February (DJF) are investigated. The results indicate that the precipitation of global, NH and SH experienced decadal change: a minus-trend from 1974s global precipitation for DJF, regression coefficient is -0.017mm/a. The precipitation of northern hemisphere has a significant negative trend, lapse rate of precipitation during DJF is -0.028mm/a .for the southern hemisphere , hasn't pass the statistical significance .The flood/drought years are pick out in 1948-2001 for DJF over global, northern and southern hemisphere, six large-scale areas, the results point out has significant decadal change in The flood/drought years of global ,NH and SH in DJF,during 1940s-1970s global flood in DJF occurred frequently and from 1970s-1990s global drought in DJF occurred frequently. The flood/drought characteristics of Northern Hemisphere are agreed with ones of the global. There is no obvious correlation between the northern and southern hemispheric flood/drought in DJF. Eurasia, North America, Antarctica has significant Interdecadal change of The flood/drought during DJF. Global has a significant contrast of rainfall between flood/drought years. The correlations among six large-scale areas precipitation are analysed. Study shows that the relationships of precipitation are exist among the Eurasia and Africa (The correlation coefficients is 0.34), Antarctica and Eurasia, Antarctica and South America, the relations between rainfall in global land during \JJfi and wind fields, SST and ENSO are discussed. The results show that drought or flood in global land and large-scale areas correspond to the singularity of wind well in the same term,In addition, the global rainfall is coherent with SST to a certain degree.