文献类型：期刊文献

英文题名：Seasonal variations of nitrate dual isotopes in wet deposition in a tropical city in China

作者：Chen, Fajin[1,2];Lao, Qibin[1,2];Jia, Guodong[3];Chen, Chunqing[1,2];Zhu, Qingmei[1,2];Zhou, Xin[1,2]

机构：[1]Guangdong Ocean Univ, Guangdong Prov Key Lab Coastal Ocean Variat & Dis, Zhanjiang 524088, Peoples R China;[2]Guangdong Ocean Univ, Coll Ocean & Meteorol, Zhanjiang 524088, Peoples R China;[3]Tongji Univ, State Key Lab Marine Geol, 1239 Siping Rd, Shanghai 200092, Peoples R China

年份：2019

卷号：196

起止页码：1

外文期刊名：ATMOSPHERIC ENVIRONMENT

收录：SCI-EXPANDED(收录号：WOS:000451492300001)、、Scopus(收录号：2-s2.0-85054459312)、WOS

基金：This work was supported by National Natural Science Foundation of China (41476066), Guangdong Natural Science Foundation of China (2016A030312004), International Science and technology cooperation project (GASI-IPOVAI-04), National Key Research and Development Plan (2016YFC1401403), Project of Enhancing School with Innovation of Guangdong Ocean University (GDOU2014050201, GDOU2013010203,GDOU2013050201). The authors would like to thank Xijie Yin for technical support in Third Institute of Oceanography, State Oceanic Administration.

语种：英文

外文关键词：Dual nitrate isotopes; Wet deposition; NOx oxidation pathways; Nitrogen source; Tropical area

外文摘要：Monthly analytical results for more than two years long of delta N-15 and delta O-15 of nitrate in wet deposition are reported for a tropical city of Zhanjiang in the southernmost mainland China, in an effort to elucidate NOx sources and its oxidation pathways to nitrate. The results showed that monthly variations of delta O-18 NO3- responded well to changes in sunshine hours, with lower delta O-15-NO3- values corresponding to longer sunshine hours. This pattern suggests that NO oxidation via the OH radical was the predominant pathway, which, by estimate, accounted for 87% in winter and 94% in summer, for nitrate formation. Remarkably, we found that the delta O-18-NO3- here are prominently low relative to previous studies, likely due to that annual sunshine hours in this tropical city is relatively long. Moreover, available data of reported delta O-18-NO3- in wet deposition showed an increasing trend with latitude, reflecting a shift of the predominant NOx oxidation pathways from those via the OH radical in low latitudes to those via O-3 in high latitudes, corresponding to the decrease of sunshine hours. A temporarily co-variation of delta O-15-NO3- and delta O-18-NO3- was observed, exhibiting higher values in dry winter and lower values in wet summer, which was attributed to the washout effect on the dual isotopes. During wet seasons, complete nitrate washout suggests that delta N-15-NO3- in precipitation should be similar to the nitrate formed in the atmosphere, and thereby can be used for source apportionment. A Bayesian model showed that the source of atmospheric nitrate deposition is mainly natural (61%) in Zhanjiang, with less anthropogenic contribution.