广西降水非均匀性多尺度特征与综合评价

Multi-scale Characteristics and Comprehensive Evaluation of Precipitation Heterogeneity in Guangxi

针对广西降水时空分配不均、旱涝灾害频发的现象,开展降水非均匀性多尺度特征和综合评价,可为区域应对旱涝灾害及水资源智慧管理提供科学支撑。基于1961-2017年广西87个格点的逐日降水资料,采用降水集中度(PCD)、降水集中期(PCP)指数构建日、候、旬、月、季多时间尺度的降水非均匀性等级评价体系,借助R/S分析和地理空间分析方法讨论了广西时空演变和气候分区特征。研究表明:日、候、旬尺度的PCD和PCP时空变化特征相对一致,较月、季尺度更能表达广西降水的非均匀性特征;广西降水的PCD历时变化在东北地区主要呈现递增趋势,而在西南地区主要呈递减趋势,其未来一段时期的变化趋势与历时演变相同;广西降水的PCD空间分布存在显著的空间自相关性和分层异质性,主要表现在PCD的均值、变异系数和发生频率上;广西降水的综合非均匀性总体呈现东北部地区高度分散、南部地区高度集中、西北和中部地区则为轻度集中或分散的分布格局。月以内的时间尺度是表达广西降水非均匀性的最佳尺度,若要考虑侯、旬尺度更加稳定和日尺度更加精细的优势,则采用候尺度进行逐日滑动计算分析将是最佳方式。

Aiming at the uneven spatial and temporal distribution of precipitation and frequent occurrence of drought and waterlogging disasters in Guangxi,the multi-scale characteristics and comprehensive evaluation of precipitation heterogeneity can provide scientific support for regional response to drought and waterlogging disasters and intelligent management of water resources.Based on the daily precipitation data of 87 grid points from 1961 to 2017 in Guangxi,the Precipitation Concentration Degree(PCD)and Precipitation Concentration Period(PCP)index were used to build day,pentad,ten days,month,season precipitation heterogeneity of multiple time scale level evaluation system.By using R/S analysis and geographical spatial analysis methods,the space-time evolution characteristics and climate division in Guangxi were discussed.The study showed that the spatial and temporal variation characteristics of PCD and PCP at the diurnal,synoptic and monthly scales were relatively consistent,and the heterogeneity of precipitation in Guangxi could be better expressed than that at the monthly and seasonal scales.The diachronic change of PCD in precipitation in Guangxi shows an increasing trend in northeast China and a decreasing trend in southwest China,and the trend of its future period is the same as the diachronic evolution.The spatial distribution of PCD in Guangxi has significant spatial autocorrelation and stratification heterogeneity,which are mainly reflected in the mean value,coefficient of variation and frequency of PCD.The comprehensive heterogeneity of precipitation in Guangxi is highly dispersed in the northeast,highly concentrated in the south,and slightly concentrated or dispersed in the northwest and central regions.The timescale within a month is the best scale to express the non-uniformity of precipitation in Guangxi.If the advantages of more stable climatic and ten-day scales and more fine daily scales are taken into account,the use of climatic scale for daily sliding calculation and analysis will be the best way.