江西信江一级支流丰溪河流域大气降水特征分析

Characteristics of Atmospheric Precipitation in Fengxi River Basin,First Tributary of Xinjiang River,Jiangxi Province

为了解江西省上饶市年内降雨变化特征,以上饶市丰溪河流域内降雨为研究区域,收集2020年3月至2021年2月中24 h降雨量大于等于5 mm的降雨。主要监测降水pH、电导率和常量离子浓度,以得到丰溪河流域内大气降水水质时空分布规律。调查数据结果表明:丰溪河降水时间分布极不均,降雨主要集中在3—9月,占全年降雨总量的87.1%,降雨量极差为657.8 mm,流域降雨呈现从南到北逐渐增强趋势,年最大降雨量流域北部的鹤山,年最小降雨量出现在流域南部的下会坑;酸雨频率为26.2%,全年pH平均值为5.79,有显著的季节差异,冬季<春季<秋季<夏季;SO^(2-)_(4)、NH_(4)^(+)、Ca^(2+)和NO^(-)_(3)为降水中主要离子,总无机离子加权平均浓度顺序为冬季>春季>秋季>夏季,与降水量呈负相关;降水离子与降水量加权年平均浓度分布规律为城区>郊区>农村>山区背景值站;SO^(2-)_(4)/NO^(-)_(3)在1.66~4.91之间,平均值2.16,属硫酸-硝酸的混合型污染,人为源对大气环境产生了一定影响。

In order to understand the annual rainfall variation characteristics of Shangrao city,Jiangxi province,taking the rainfall in Fengxi river basin of Shangrao city as the research area,the rainfall with a rainfall of greater than or equal to 5 mm in 24 hours from March 2020 to February 2021 was collected.It mainly monitored precipitation pH,conductivity and constant ion concentration to obtain the temporal and spatial distribution law of atmospheric precipitation water quality in Fengxi river basin.The results of the survey data show that the precipitation time distribution of Fengxi river is extremely uneven.The rainfall is mainly concentrated from March to September,accounting for 87.1%of the total rainfall of the whole year,and the rainfall range is 657.8 mm.The rainfall in the basin has gradually increased from south to north.In Heshan in the northern part of the basin,the annual minimum rainfall occurs in the Xiahuikeng in the southern part of the basin.The frequency of acid rain is 26.2%,and the annual average pH value is 5.79,with significant seasonal differences,winter<spring<autumn<summer.It is negatively correlated with precipitation.The distribution law of precipitation ion and precipitation weighted annual average concentration is urban area>suburb>rural area>mountain background value station;SO^(2-)_(4)/NO^(-)_(3) is between 1.66~4.91,with an average value of 2.16.It is a mixed pollution of sulfuric acid and nitric acid.Man-made sources have a certain impact on the atmospheric environment.