Estimation of atmospheric NO2dry deposition in Huaihe River Basin based on TROPOMI
Based on Sentinel-5P TROPOMI,we retrieved the surface NO2 concentration in the Huaihe River Basin(HRB)during 2018～2020 by using random forest(RF),and the estimation method was used to obtain the dry deposition flux of NO2.We then divided the HRB into four areas(water,agriculture,urban,and vegetation)to estimate the nitrogen contribution of atmospheric NO2 dry deposition to the HRB water.The results show that the model simulation result is in good agreement with the measured data,achieving a correlation coefficient(R)of 0.94,a mean absolute error(MAE)of 2.7,and a root mean square error(RSME)of 4.1 in surface NO2 estimation.There is a clear seasonal variation in the NO2 dry deposition flux and surface NO2 concentration in the HRB.The average surface NO2 concentration in spring,summer,autumn,and winter was 13.7,12.2,17.6,23.1μg/m3;the average dry deposition flux of NO2 was 1.25,1.13,1.61,2.13kg N/(hm2·a).The surface NO2 concentration and dry deposition flux in HRB are higher in the north and south,and lower in the east and west.NO2 dry deposition in agriculture was a major contributor with 83.47％.In 2019,the overall atmospheric NO2 dry deposition in HRB was 1.34× 105t,and its contribution to water nitrogen was 1.36× 104t N;In 2020,the overall atmospheric NO2 dry deposition was 1.25× 105t,and the contribution of NO2 to water nitrogen is 1.18× 104t N.
NO2 dry depositionTROPOMIrandom forestHuaihe River Basinnitrogen contribution
万方数据
