Temporal and Spatial Variation of Wet Deposition of Nitrogen in the Source Region of the Yangtze River

Abastract：As the source of the longest river in Asia，the source region of the Yangtze River is great significance to explore its nitrogen deposition characteristics for protecting the safety of water sources in China. The result shows：（1）From April 2016 to July 2018，the average concentrations of NO - N、NO - N and NH - N were 1.01 mg/L，2.45 mg/L and 1.30 mg/L respectively ，the average deposition of NO-N 、NO-N and NH-N were 0.02 kg/hm 、0.09 kg/hm 、0.30 kg/hm. Qumalai had the highest proportion to the overall nitrogen deposition concentration in the source region of the Yangtze River ，followed by the Tuotuo River ，Zhimenda was the smallest ，and the nitrogen deposition in spring and summer was higher than that in autumn and winter.（2） There was a logarithmic function relationship between nitrogen concentration and precipitation ，and a positive power function relationship between deposition and precipitation ；NO - N and NO - N deposition were negatively correlated with temperature ，and NH -N was positively correlated with temperature.（3） The increase in NH -N deposition in the source region of the Yangtze River in summer is mainly due to grazing by herdsmen ，and the increase in NO - N deposition in winter is mainly due to coal combustion ，and the transmission of pollutants is also affected by westerly circulation and local circulation ，and overseas sources are more concentrated in West Asia.