基于水量平衡的长江上游地区气象水文要素时空变化特征分析

Spatial and Temporal Variation Characteristics of Meteorological and Hydrological Elements in Upstream Yangtze River Based on Water Balance

基于1980—2019年长江上游地区的逐月气温、降水数据,采用一元线性回归、F趋势检验、水量平衡分析、质心识别等方法,揭示了长江上游地区近40 a来气象水文要素的时空分布特征和变化规律。研究结果表明:①长江上游地区年均气温、年均降水量和年均蒸发量的空间分布均呈现由东南向西北逐渐降低的趋势,年均土壤蓄水变化量有着较大的空间差异。②1980—2019年期间长江上游地区气温上升的趋势较为明显,变化率为0.39℃/(10 a);年降水量整体变化不大,增加的区域主要位于金沙江石鼓以上;整个长江上游地区年均蒸发量变化率为6.08 mm/(10 a),其中,金沙江石鼓以上、金沙江石鼓以下、嘉陵江流域和岷沱江流域增加趋势明显;年均土壤蓄水变化量整体有略微下降,变化率为-6.144 mm/(10 a)。③长江上游地区气温质心经度、纬度变化的倾斜率分别为-0.03°/(10 a)和0.01°/(10 a),蒸发质心经纬度变化的倾斜率分别为-0.04°/(10 a)和0.02°/(10 a);降水质心和土壤蓄水变化量质心的经度倾斜率分别为-0.06°/(10 a)和-0.01°/(10 a)。各气象水文要素空间质心均呈现出向西北方向移动的趋势,说明从空间分布上来看,西北地区的气温、降水、蒸发和土壤蓄水变化量均有所增加。

Based on the monthly temperature and precipitation data in the upstream of the Yangtze River from 1980 to 2019,we revealed the spatial and temporal distribution characteristics and variation rules of meteorological and hydrological elements in the upstream of Yangtze River in the past four decades via unary linear regression,F trend test,water balance analysis,centroid identification and other methods.Results unveiled that:1)The average annual temperature,average annual precipitation,and average annual evaporation in the upstream of Yangtze River showed a trend of gradual decline from the southeast to the northwest,and the average annual soil water storage variation differed greatly spatially.2)Temperature in the upstream of Yangtze River climbed remarkably from 1980 to 2019,with a change rate of 0.39℃/(10 a).Annual precipitation as a whole changed rarely,and the increased area was mainly located above Shigu station of Jinsha River.The inclination rate of annual evaporation in upstream Yangtze River was 6.08 mm/(10 a),of which the upper and lower reaches of Shigu station of Jinsha River,Jialing River basin,and Minjiang-Tuojiang River basin witnessed obvious growth trend.Average annual soil water storage variation decreased slightly as a whole,with a change rate of-6.14 mm/(10 a).3)The longitude and latitude inclination rate of temperature centroid in upstream Yangtze River was-0.03°/(10 a)and 0.01°/(10 a),respectively,and those of evaporation centroid was-0.04°/(10 a)and 0.02°/(10 a),respectively.The longitude inclination rate of the centroid of precipitation and water storage variation was-0.06°/(10 a)and-0.01°/(10 a),respectively.The spatial centroid of all meteorological and hydrological elements showed a trend of moving towards the northwest,which implied that the air temperature,precipitation,evaporation,and water storage all increased in the northwest from the perspective of spatial distribution.