广东北江流域降水集中度和集中期的时空变化特征

Spatio-temporal change characteristics of PCD and PCP in Guangdong Beijiang river basin

基于广东北江流域分布较均匀的18雨量站1965年-2009年日降水资料,统计出各站各年份降水集中度(PCD)和集中期(PCP)指标,然后基于该指标分析流域降水集中度和集中期多年均值、变化趋势、与年降水量相关性、丰水年枯水年合成分析的空间分布情况,以期研究流域降水年内非均匀分布的时空变化特征。结果表明:(1)降水集中度总体表现为从南向北递减;降水集中期主要表现为中北部的大部分区域较为提前,南部区域较为滞后。(2)大部分区域表现为年降水量随着降水集中度的下降而增加;南部区域年降水量随着降水集中期的滞后而减少,北部区域反之。(3)MK趋势检验表明,流域降水集中度、集中期均主要表现为上升,但不显著。(4)降水集中度空间分布上,丰水年与枯水年比较一致,但枯水年降水集中度更高;丰水年降水集中期差别较大,从流域平均来看,丰水年集中期较枯水年约滞后20天。

Based on the daily precipitation data between1965and-009from18rainfall stations in Guangdong Beijiang river basinand the definitions of Precipit ation Concentration Deg ree(PCD)and Precipitation Concentration Perio d(PCP),this paper stud-ied the intr a-annual inhomogeneo us distribution char acteristics of the precipitation in the basin by analyzing the spatial distribu-tion of the multi-year mean values,variation tr end,cor relation with annual precipitation,and wet-year and dry-year composit evalues of PCD and PCP.The results are as follows:(1)PCD g enerally decr eased from south to north;PCP wasear lier in mostofthe north-centr al basin,but relatively later in the southern basin.(2)Annual precipitation would incr ease as PCD decreased inmost of the basin;as PCP dela yed,annual precipitation in t he southern basin w ould decrease but that in the northern basinwo uld incr ease.(3)As the Mann-Kendall test showed,the PCD and PCP in the basin w ere mainly on the rise,but not in a sig nif-icant manner.(4)The spatia l distributio n o f PCD in w et y ears w as similar to that in dr y y ears,but the PCD o f dry y ea rs w ashigher.The PCPs in wet years were much more varied than those in dry years.On average,the PCP in wet years lagged about20days behind that in dry years.