利用湖北1961—2014年站点逐日降水资料及人口和人口城乡构成数据,通过平均值分离、最小二乘法拟合、趋势系数和气候倾向率分析、M-K检验和累积距平检验等方法,从时空分布、趋势变化、局地特征等方面,分析了近54 a湖北极端降水的变化特征及其与城市化的关系,结果表明:(1)对于第95百分位的极端降水事件,湖北极端降水阈值的范围为43.5~85.1 mm,大部分站的阈值在暴雨雨量范围,高阈值区位于江汉平原和鄂东,低阈值区位于鄂西北,最高阈值出现在武汉站,最低阈值出现在竹山站和房县站.(2)近54 a来湖北多年平均的极端降水日(Dep)、极端降水量(Pep)、极端降水强度(Iep)、最大5 d降水(R5 d)和雨量比均存在明显的区域特征,但Iep、R5 d的地域差异不如Dep、Pep明显.鄂西南南部以及鄂东南东部和南部是极端降水事件的高发区,鄂西北北部是极端降水事件的低发区.(3)极端降水指数(R)能反映极端降水的强弱,其大尺度存在明显的年际差异,而长期变化趋势不显著,Pep、Iep和雨量比呈弱增加趋势,R5 d和极端降水频数呈弱减少趋势.(4)城市化发展速度会改变R及其局地距平百分比DRij、趋势系数和气候倾向率的空间分布.随着城市化发展速度加快,湖北城市"雨岛效应"的格局发生了变化,Dep、Pep、Iep、R5 d及其DRij从南北差异明显变为东西差异明显,江汉平原和鄂东的Dep、Pep、Iep、R5 d增加,而鄂西南的减少,且四者趋势系数通过显著性水平检验的站点数更多,气候倾向率绝对值也普遍增大,但大部分站点的变化趋势为负值.(5)湖北极端降水具有明显的城市效应,城市化发展速度较快的大城市代表站的极端降水阈值大于配对的小城市代表站,两种代表站平均的Dep、Pep、Iep、R5 d的年际变化较一致,但大城市代表站的Iep、R5 d普遍较大,极端降水的变化趋势更明显.%Based on the daily precipitation data,as well as population,population composition data of urban and rural areas in Hubei Prov-ince from 1961 to 2014,by using methods such as mean separation,least-squares fitting,trend coefficient and climate trend analysis,M-K and cumulative distance test,the characteristics of extreme precipitation and its relationship with urbanization are analyzed from the aspects of spatio-temporal distribution,trend change and local characteristics in recent 54 years.The results show that:(1)For the extreme precipita-tion events of 95th percentile,extreme precipitation threshold range is from 43.5 to 85.1 mm,and thresholds of most stations are in the range of rainstorm in Hubei.The two high threshold areas are located in Jianghan Plain and east of Hubei,while the low threshold area is located in northwest of Hubei.The highest threshold appears at Wuhan station,and the two lowest thresholds appear at Zhushan and Fangxian station. (2)Extreme precipitation days(Dep),extreme precipitation(Pep),extreme precipitation intensity(Iep),maximum 5 d precipitation(R5 d)and rain-fall ratio have distinct regional characteristics in Hubei,although the regional differences for Iepand R5 dare less than those for Depand Pep.The southern region of southwest of Hubei, eastern and southern region of southeast of Hubei are high incidence areas of extreme precipitation events,and northwest of Hubei is low incidence area.(3)The extreme precipitation index(R)can reflect extreme precipitation intensity.There are obvious interannual differences on the large scale,although the long-term trend is not significant.Pep,Iepand rainfall ratio have a weak in-creasing trend,and R5 dand extreme precipitation frequency have a weak decreasing trend.(4)The urban development speed changed the spa-tial distribution of R and their local distances,trend coefficients and climate tendencies.With the urbanization in Hubei,the pattern of"rain island effect"has changed. Dep,Pep,Iep,R5 dand vary from obvious north-south difference to obvious east-west difference.Dep,Pep,Iep,and R5 d increased in Jianghan Plain and east of Hubei,but decreased in southwest of Hubei.The number of stations whose trend coefficients pass the significance level test becomes more. The absolute values of climate tendencies are generally increased,while the changes at most of stations are negative.(5)Extreme precipitation in Hubei has obvious urban effect,extreme precipitation thresholds at metropolitan-representative sta-tions with faster urbanization are more than that of the matching small city-representative stations.The interannual variation of average Dep, Pep,Iep,and R5 dof two kind of representative stations are consistent,while Iepand R5 dat metropolitan-representative stations are generally more,and the trend of extreme precipitation is more obvious.
展开▼
