1. 生态环境部卫星环境应用中心，北京 100029
2. 国家环境保护卫星遥感重点实验室，北京 100101
3. NOAA Center for Satellite Applications and Research, College Park, MD 20740, USA
4. 中国科学院遥感与数字地球研究所，遥感科学国家重点实验室，北京 100101
5. 中国地质大学，湖北 武汉 430074
Temporal and Spatial Characteristics of Nitrous Oxide Concentration in China
MA Peng-fei1, 2, XIONG Xiao-zhen3, CHEN Liang-fu4, TAO Ming-hui5, CHEN Hui1, 2, ZHANG Yu-huan1, 2, ZHANG Li-juan1, 2, LI Qing1, 2, ZHOU Chun-yan1, 2, CHEN Cui-hong1, 2, ZHANG Lian-hua1, 2, WENG Guo-qing1, 2, WANG Zhong-ting1, 2*
1. Satellite Environment Center, Ministry of Ecology and Environment, Beijing 100029，China
2. State Environmental Protection Key Laboratory of Satellite Remote Sensing, Ministry of Environmental Protection, Beijing 100101, China
3. NOAA Center for Satellite Applications and Research, College Park, MD 20740, USA
4. The State Key Laboratory of Remote Sensing Science，Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences, Beijing 100101, China
5. China University of Geosciences, Wuhan 430074, China
Abstract：Retrieves nitrous oxide profiles from the thermal infrared satellite data, the results will be affected by the impact of atmospheric parameters such as atmospheric temperature and humidity profiles, as well as surface parameters such as surface temperature and surface emissivity and the like. N2O own changes to a lesser extent, so when using the optimal estimation inversion, to get a priori profile and to select the inversion channel are the keys. Therefore, the inversion of nitrous oxide is rarely seen in China. Study and analyze the absorption characteristics of nitrous oxide and other interfering gases in the thermal infrared region for channel selection, based on this, to retrieve and analyze the temporal and spatial variation characteristics of nitrous oxide concentrationis of great practical significance for the study of global climate change in China. In this paper, under the inversion framework of the optimal estimation method, an optimal sensitive profile channel selection method is used to retrieve the nitrous oxide concentration using the AIRS data. Compared with the Canadian station in the TCCON observation network, the results show that the retrieval results are in good agreement with the ground observations, and the correlation coefficient r is 0.73. This algorithm can be extended to the thermal infrared hyperspectral data such as IASI and CrIS, and increase the observation data of nitrous oxide to more than 20 years. This long-time series product is an effective supplement to the current ground observation. The annual and monthly mean changes of nitrous oxide and its spatial distribution characteristics in China are analyzed for the first time. The results show that the change of thenitrous oxide concentration is obvious with time and latitude, among which the annual change of the nitrous oxide concentration is small, and the monthly and seasonal meanvalue changes greatly. From January of each year, the concentration of nitrous oxide increased month by month, reached the maximum in July and August, and then began to decline month by month. The seasonal variation was the highest in summer (June-gust), spring and autumn are the second, while winter is the lowest. According to the annual average, the concentration of nitrous oxide in China changes obviously with latitude, and the higher the latitude is, the lower the concentration is. High-value regions are mainly concentrated in South China, especially in summer. The low-value regions are north China and southwest China. In the west of China, the concentration of nitrous oxide is higher in summer. In addition to local emissions, this seasonal or monthly mean change is also affected by air convection and transport.
Key words：Thermal infrared data; Nitrous oxide concentration; Temporal and spatial distribution characteristics
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