摘要
氮沉降对全球尺度的粮食生产、碳氮循环及大气环境质量均具有重要影响.本研究采用WRF-Chem模式对区域氮沉降过程进行数值模拟,着重分析氮干沉降的时空分布特征.结果表明:在空间场上,我国氮干沉降主要体现出东高西低的特点,华北平原和川渝地区为氮沉降高值区,这主要与排放高值区的空间分布有关,NH和HNO沉降量都是在东部最大,这与东部一直以来较高的经济增长速度和农业活动水平有直接联系.从氮的不同组分形式(气态/颗粒态氮或者氧化性/还原性氮)来看,气态氮较颗粒态氮对总氮沉降的贡献更大,贡献比达66%;相较氧化性氮,还原性氮对总氮沉降的贡献较大,贡献比为57%.进一步分析不同下垫面类型的氮干沉降结果,气态氮的干沉降均是在城市和农田下垫面上更高.NH干沉降通量主要受排放源影响,HNO_(3)干沉降通量则受气象条件影响较大,而排放源和气象条件均有很强的季节性变化.NH_(4)^(+)和NO_(3)^(-)在森林下垫面上的干沉降通量远多于其它类型的下垫面,这主要是因为森林下垫面粗糙度比较大,相应的摩擦速度也较大,湍流比较活跃,有利于粒子污染物的沉积.
Nitrogen deposition plays an important role in global grain production,carbon and nitrogen cycling and atmospheric environmental quality.In this study,the WRF-Chem model was used to conduct numerical simulation of regional nitrogen deposition process,focusing on the analysis of spatial and temporal distribution characteristics of nitrogen dry deposition.Results showed that in the space field,the nitrogen dry deposition in China was mainly characterized by high nitrogen dry deposition in the east and low nitrogen dry deposition in the west,and the North China Plain,Sichuan and Chongqing were regions of high nitrogen dry deposition,which was mainly related to the spatial distribution of the high emission.The deposition of NHand HNOwas the largest in the east,which was directly related to the high economic growth rate and agricultural activity level in the east.From different nitrogen forms(e.g.,gaseous or particulate nitrogen,oxidizing or reducing nitrogen),gaseous nitrogen contributed more to the total nitrogen deposition than particulate nitrogen,with a contribution ratio of 66%.Compared with oxidizing nitrogen,reducing nitrogen contributed more to total nitrogen deposition,with the contribution ratio of 57%.Further analysis of nitrogen dry deposition of different underlying surface types showed that the dry deposition of gaseous nitrogen was higher in urban and farmland.The dry deposition flux of NH_(4)^(-)was mainly affected by emission sources,while the dry deposition flux of HNO_(3)was greatly affected by meteorological conditions,and both emission sources and meteorological conditions have strong seasonal variations.The dry deposition flux of NH_(4)^(-)and NO_(3)^(-)on the forest was much higher than that of other types of underlying surface,mainly because the roughness of the forest was relatively large,the corresponding friction velocity was also relatively large,and the turbulence was relatively active,which was conducive to the deposition of particle pollutants.
作者
周慧娴
沈傲
崔寅平
田春艳
刘一鸣
卢骁
王雪梅
樊琦
ZHOU Huixian;SHEN Ao;CUI Yinping;TIAN Chunyan;LIU Yiming;LU Xiao;WANG Xuemei;FAN Qi(Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies,School of Atmospheric Sciences,Sun Yat-sen University,Guangzhou 510275;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082;Meteorological Center of Middle South Regional Air Traffic Management Bureau of CAAC,Guangzhou 510000;Institute for Environmental and Climate Research,Jinan University,Guangzhou 511443)
出处
《环境科学学报》
CAS
CSCD
北大核心
2022年第10期129-137,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.42075181)
国家重点研发计划大气专项课题(No.2017YFC0210105,2019YFC0214605)
广东省科技计划项目(科技创新平台类)(No.2019B121201002)。
关键词
氮
WRF-Chem模式
干沉降
沉降通量
不同组分
下垫面类型
nitrogen
WRF-Chem model
dry deposition
deposition flux
different components
underlying surface type
