李鸿雁杨巍李峰平
摘要:基于嫩江流域17個气象站点1959—2010年逐日降水数据,选取降水量、降水日数和降水强度作为代表性指标,采用Mann-Kendall趋势检验法和线性回归法系统研究了嫩江流域降水的时空变化特征。结果显示:近51年来,①嫩江流域平均年降水量、夏季和秋季降水量分别以6mm/(10a)、4mm/(10a)和5 mm/(10a)的速率呈下降趋势,而春、冬两季降水量分别以2mm/(10a)和1mm/(10a)的速率增加;空间上,年降水量和季节降水量在流域上游多于下游。②嫩江流域平均年、夏季和秋季降水日数分别以1.5d/(10a)、1.1d/(10a)和1.2d/(10a)的速率下降,且上游下降较明显;春、冬两季降水日数则以0.1d/(10a)、0.7d/(10a)的速率呈增加趋势,且中游增加趋势明显;流域降水日数在年和季节尺度上均表现出上游多于下游的空间特征。③嫩江流域平均年降水强度、夏季和秋季降水强度分别以-0.018mm/(d·10a),-0.007mm/(d·10a)和-0.105mm/(d·10a)下降,而春、冬两季降水强度分别以0.051mm/(d·10a)和0.047mm/(d·10a)上升;空间上,年和春、夏、冬3个季节降水强度表现为流域上游弱于下游,而秋季降水强度在嫩江中游干流附近较大,其他地区降水强度较小。结果表明,在全球气候变化下,嫩江流域年和季节的降水特征在1959—2010年间均有不同程度改变,并呈现出明显的空间分布特征。
关键词:嫩江流域;降水量;降水日数;降水强度;降水特征
中图分类号:P467
DOI:10.16152/j.cnki.xdxbzr.2020-03-013
The spatiotemporal distribution of precipitationcharacteristics in Nenjiang River Basin
LI Hongyan, YANG Wei, LI Fengping
Abstract: Based on the daily precipitation data of 17 meteorological sites in the Nenjiang River Basin from 1959 to 2010, precipitation amount, precipitation days and precipitation intensity were selected as representative indicators, and the spatial and temporal change characteristics of precipitation in Nenjiang Basin were studied by Mann-Kendall trend test and linear regression method.The results show that, for nearly 51 years: ①The average annual precipitation in the Nenjiang Basin, the precipitation in summer and autumn decreased at the rate of 6mm/(10a), 4mm/(10a) and 5 mm/(10a), respectively, while the precipitation in spring and winter increased at a rate of 2mm/(10a) and 1mm/(10a); spatially, annual and seasonal precipitation in the upstream is more than downstream. ② The average annual, summer and autumn precipitation days in the Nenjiang Basin decreased at a rate of 1.5d/(10a), 1.1d/(10a) and 1.2d/(10a) respectively, and the decrease in the upstream was more obvious; the number of days of precipitation in the basin showed the spatial characteristics that is more in upstream than downstream on the year and seasonal scale. ③ The average annual precipitation intensity, summer and autumn precipitation intensity in the Nenjiang Basin decreased by -0.018mm/(d.10a),-0.007mm/(d.10a) and-0.105mm/(d.10a), while the inereasing rate precipitation intensity in the spring and winter seasons was 0.051mm/d.10a and 0.047mm/da.Precipitation intensity of spring, summer and winter is shown to be weaker in the upper reaches of the basin than downstream, while the precipitation intensity in autumn is larger near the main stream in the middle of the Nenjiang River.The results show that under global climate change, the annual and seasonal precipitation characteristics in the Nenjiang River Basin during 1959—2010 have changed in different degrees, and exhibit obvious spatial distribution characteristics.
Key words: Nenjiang River Basin; precipitation amount; precipitation days; precipitation intensity; precipitation characteristics
降水是最重要的水文气象要素之一,同时也是全球水循环的关键组成部分[1],也是最为活跃的要素。20世纪以来,全球平均气温明显升高[2-3],严重影响全球和区域水文循环[4-6],加剧了降水的时空分布差异性[7-8]。研究发现,近半个世纪我国平均年降水量呈现出比较明显的年代和多年代尺度波动[9-13]。降水的趋势性变化将对区域生态系统状况、河流、湖泊等水文过程产生深刻影响[14-15]。因此,变化环境下降水时空变化研究引起了气象、水文、生态等领域的高度关注。
嫩江流域地处我国东北中高纬度地区,对全球变化具有高度的敏感性[16-17]。近年来,许多学者围绕东北地区降水变化情况进行研究,并取得了较大进展。唐蕴等[18]对东北地区1951—2000年间降水的时空分异特征进行了分析,得出东北地区降水整体上呈现下降趋势,且具有明显的周期性;陆志华等[19]分析了松花江流域1960—2010年的年降水和四季降水的时空变化特征;缪驰远等[20]对嫩江、哈尔滨两地48年的夏季降雨量多时间尺度变化特征进行了研究。目前,针对东北地区降水的研究大多侧重于对降水量的分析,而对降水日数、降水强度等降水特征指标的分析相对较少。因此,