生态环境学报 ›› 2024, Vol. 33 ›› Issue (2): 231-241.DOI: 10.16258/j.cnki.1674-5906.2024.02.007

• 研究论文【环境科学】 • 上一篇    下一篇

基于OCO-2遥感数据的新疆维吾尔自治区大气XCO2空间化研究

张杨1(), 徐永明1,*(), 卢响军2, 莫亚萍1, 吉蒙1, 祝善友1   

  1. 1.南京信息工程大学遥感与测绘工程学院,江苏 南京 210044
    2.新疆生产建设兵团生态环境第一监测站,新疆 乌鲁木齐 830011
  • 收稿日期:2023-09-07 出版日期:2024-02-18 发布日期:2024-04-03
  • 通讯作者: *徐永明。E-mail: xym30@263.net
  • 作者简介:张杨(1999年生),女,硕士研究生,研究方向为大气环境遥感。E-mail: 20211211035@nuist.edu.cn
  • 基金资助:
    新疆生产建设兵团重点领域科技攻关计划(2022AB016);石河子市重点领域科技攻关计划(2022NY03)

Spatialization of Atmospheric XCO2 in Xinjiang Uygur Autonomous Region based on OCO-2 Remote Sensing Data

ZHANG Yang1(), XU Yongming1,*(), LU Xiangjun2, MO Yaping1, JI Meng1, ZHU Shanyou1   

  1. 1. School of Remote Sensing & Geomatics Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, P. R. China
    2. The First Ecological and Environment Monitoring Station of Xinjiang Production and Construction Corps, Urumchi 830011, P. R. China
  • Received:2023-09-07 Online:2024-02-18 Published:2024-04-03

摘要:

二氧化碳(CO2)是导致全球变暖最主要的温室气体,掌握准确的CO2空间分布信息可以有效评估碳减排成效,对于推进碳达峰、碳中和工作具有重要意义。相比站点观测,碳卫星能够获取大尺度的CO2分布信息,但是由于其幅宽较窄以及云覆盖的影响,大气CO2卫星遥感数据存在大量缺值区域,不能获得空间连续的大气CO2分布。以新疆维吾尔自治区为研究区,基于2019年OCO-2卫星大气二氧化碳柱平均干空气混合比(XCO2)数据,结合气温、地形、植被、大气NO2浓度等相关变量,综合对比了多元线性回归(MLR)、地理加权回归(GWR)、支持向量机(SVR)、随机森林(RF)、极端梯度提升树(XGBoost)和极端随机树(ERT)等方法在生成大气XCO2空间连续数据中的表现。交叉验证结果表明,RF、XGBoost和ERT这3种集成学习模型精度明显优于SVR、GWR和MLR模型,其中ERT模型精度最高,决定系数R2为0.748,平均绝对误差σMAE为0.489×10−6。基于ERT模型生成了新疆2019年逐月大气XCO2空间连续数据,该地区大气XCO2空间差异和季节变化都很明显。在空间分布格局上总体呈现与地形“三山夹两盆”相似的空间分布特征,裸地XCO2年均值最高,林地和草原的XCO2年均值最低;季节变化特征与植被生长周期相似,春冬季浓度较高,夏秋季浓度较低,最高值出现在4月,最低值出现在8月,不同土地覆盖类型的大气XCO2季节变化与全区域类似,其中草原和林地的季节差异最大,裸地季节差异最小。该研究为基于碳卫星遥感数据生成时空连续的大尺度XCO2数据提供了参考和借鉴。

关键词: OCO-2, XCO2, 卫星遥感, 集成学习模型, 空间化, 时空分布, 新疆维吾尔自治区

Abstract:

Carbon dioxide (CO2) is a primary greenhouse gas that plays a crucial role in global warming. Accurate information on the spatial distribution of CO2 is imperative for assessing the efficiency of carbon emission reduction, which is important for promoting carbon peaking and neutrality. Compared to station observations, carbon satellites can obtain large-scale information on CO2 distribution. However, the narrow width and cloud coverage associated with atmospheric CO2 satellite remote sensing data contribute to numerous gaps, hindering the acquisition of spatially continuous atmospheric CO2 distribution. Using the Xinjiang Uygur Autonomous Region as the study area, this study synthetically compared the performance of several methods in generating spatially continuous atmospheric XCO2 data. Multiple linear regression (MLR) models, geographically weighted regression (GWR) models, support vector machines (SVR), random forests (RF), extreme gradient boosted trees (XGBoost), and extreme random trees (ERT) were employed to produce gap-free XCO2 data based on the column-averaged dry-air mixing ratio of CO2 (XCO2) data derived from the 2019 OCO-2 satellite and auxiliary variables, such as temperature, topography, vegetation, and atmospheric NO2 concentrations. The cross-validation results showed that the three integrated learning models, RF, XGBoost, and ERT, outperformed the SVR, GWR, and MLR models. The ERT model achieved the highest accuracy with an R2 of 0.748 and a mean absolute error of 0.489×10−6. Based on the developed ERT model, spatially continuous atmospheric XCO2 data was mapped monthly across Xinjiang in 2019. Significant spatial differences were observed in the atmospheric XCO2 within the region. The spatial distribution pattern of XCO2 exhibited a distinct correlation with the topographical characteristics commonly referred to as “three mountains and two basins.” Bare land exhibited the highest annual mean XCO2, whereas woodland and grassland exhibited the lowest values. Seasonal fluctuations in XCO2 coincided with the phenological cycles of vegetation, with peaks observed during spring and winter, and troughs during summer and autumn. The highest value was observed in April, whereas the lowest was observed in August. Across different land cover types, the seasonal variation in XCO2 was similar to the regional patterns, with grassland and woodland experiencing the most pronounced seasonal disparities and bare land the least. This study provides a valuable framework for generating spatially and temporally continuous large-scale XCO2 data using satellite XCO2 products.

Key words: OCO-2, XCO2, satellite remote sensing, integrated learning model, spatialization, spatiotemporal distribution, Xinjiang Uygur Autonomous Region

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