Abstract:The data used in this study are taken from themonthly precipitation dataset at 160 stations in China during 1951 to 2000.The precipitation-concentration degree(PCD)and precipitation-concentration period(PCP)of annual precipitation are quantitatively defined by the so-called serial,variance,and departuremethods respectively.According to the temporal variation of annual precipitation(AP),the seasonal cycle of the AP can be describedmore accurately with the help of the two parameters(PCD and PCP).Relationships of the spatial and temporal distribution patterns of PCD and PCP with the annual precipitation in China are further investigated.The computed results by using the threemethods are compared with each other.Based on the correlation coefficients between precipitation anomalies of different stations in themid-and low-reaches of the Changjiang River,the representative stations of this region are selected.The PCD and PCP at selected stations are summed up and then the time series of the regionally averaged PCD and PCP are computed,and further studied using the wavelet and trend analysis.Results show that the two parameters,PCD and PCP,both exhibit prominent interannual and interdecadal variations in this area,with the latter to bemore stable in recent 50 years.