应用大气化学模型解析华北地区大气氮沉降时空分布特征及影响因素  

Model study on the spatial and temporal variations of nitrogen deposition over North China

作　　者：林以真 李凌 赵园红 陈优帆 LIN Yizhen;LI Ling;ZHAO Yuanhong;CHEN Youfan(College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China;Key Laboratory of Physical Oceanography,Ocean University of China,Qingdao 266100,China;Sichuan Academy of Environmental Policy and Planning,Chengdu 610041,China)

机构地区：[1]中国海洋大学海洋与大气学院,青岛266100 [2]中国海洋大学物理海洋教育部重点实验室,青岛266100 [3]四川省环境政策研究与规划院,成都610041

出　　处：《地球环境学报》2023年第2期170-181,共12页Journal of Earth Environment

基　　金：山东省自然科学基金项目(ZR202102280270,2022HWYQ-066);Shandong Provincial Natural Science Foundation(ZR202102280270,2022HWYQ-066)。

摘　　要：本研究基于大气化学传输模型模拟结果,分析了2005—2015年华北地区大气氮沉降的时空分布特征,通过对2005年和2015年的结果进行模型敏感性实验,定量分析了全国和华北本地的人为源排放以及气象场对华北地区氮沉降年际变化的贡献。结果表明:(1)2005—2015年华北地区氮沉降年均量为28.7 kg·hm^(-2)·a^(-1)(以N计,余同),其中18.7 kg·hm^(-2)·a^(-1)来自还原态氮(NHx),10.0 kg·hm^(-2)·a^(-1)来自氧化态氮(NOy)。湿沉降占比为56%(16.1 kg·hm^(-2)·a^(-1)),略高于干沉降(12.6 kg·hm^(-2)·a^(-1))。氮沉降的高值主要集中在华北的东南地区,低值集中在华北的西北地区,整体呈夏季高冬季低的季节特征。(2)2005—2015年,华北地区氮沉降整体呈先增加后减少的趋势,波动范围在27.4—30.4 kg·hm^(-2)·a^(-1)。相较2005年,2015年氧化氮沉降增加了2.2 kg·hm^(-2)·a^(-1),而还原氮沉降减少了1.9 kg·hm^(-2)·a^(-1)。其中氮氧化物(NOx)和氨气(NH3)人为源排放的变化分别导致了1.0 kg·hm^(-2)·a^(-1)氧化氮沉降的增加和2.5 kg·hm^(-2)·a^(-1)还原氮沉降的减少,分别占全国人为源排放贡献的89%和53%,这说明区域传输对于2005—2015年还原氮沉降变化的影响较大。(3)华北地区干沉降的年际变化主要取决于前体物排放的变化,而湿沉降不仅受前体排放的影响,也受到降水等气象场的驱动。Background,aim,and scope The observations indicate that North China is experiencing high levels of emissions and deposition of reactive nitrogen.A thorough analysis of the spatial and temporal variations of nitrogen deposition in North China is crucial for better understanding its potential ecological and climate impacts.Materials and methods In this study,we estimated the spatial and temporal variations of nitrogen deposition over North China using the atmospheric chemistry transport model GEOS-Chem.We also quantified the contributions of national(terrestrial regions in China)and regional(North China)anthropogenic emissions and meteorological conditions to the changes in nitrogen deposition between 2005 and 2015 based on model sensitivity experiments.Results The model simulations revealed that the averaged annual total nitrogen over North China during 2005—2015 is 28.7 kg·hm^(-2)·a^(-1),with 18.7 kg·hm^(-2)·a^(-1) is from reduced nitrogen(NHx)and 10.0 kg·hm^(-2)·a^(-1) is from oxidized nitrogen(NOy).Wet deposition contributes 56%(16.1 kg·hm^(-2)·a^(-1)),slightly higher than dry deposition(12.6 kg·hm^(-2)·a^(-1)).High values of nitrogen deposition are primarily concentrated in the southeast of North China,while low values are concentrated in the northwest.Compared to 2005,reduced nitrogen deposition increased by 2.2 kg·hm^(-2)·a^(-1),while oxidized nitrogen decreased by 1.9 kg·hm^(-2)·a^(-1) in 2015.Anthropogenic emissions over North China led to a 2.5 kg·hm^(-2)·a^(-1) decrease in reduced nitrogen and a 1.0 kg·hm^(-2)·a^(-1) increase in oxidized nitrogen,contributing to 89%and 53%,respectively,of the changes driven by total anthropogenic emissions in China.Discussion In this study,we discovered that the interannual variation of oxidized nitrogen deposition in North China is consistent with its precursor NOx emissions.However,the interannual variation of reduced nitrogen deposition is quite distinct from that of NH3 emissions.Interannual variations in precipitation can significantly influence

关 键 词：氮沉降 时空分布特征 人为源排放 气象场 

分 类 号：X51[环境科学与工程—环境工程]