热带地理2025，Vol.45Issue(8)：1404-1416,13.DOI:10.13284/j.cnki.rddl.20240664
北江流域总氮遥感反演及其与土地利用关系研究
Remote Sensing Inversion of Total Nitrogen in the Beijiang River Basin and Its Relationship with Land Use
摘要
Abstract
Total Nitrogen(TN)refers to the total amount of various forms of inorganic and organic nitrogen in a water body.At present,global rivers draining into the sea are facing the problem of exceeding TN standards.Evidence suggests that TN in a basin is directly affected by land use.National and local governments attach great importance to the TN reduction projects in the Pearl River Basin.The Beijiang River Basin is an important part of the Pearl River Basin.Therefore,exploring the temporal and spatial distribution characteristics of TN concentrations and revealing their correlation with land use are of great significance to the health of the aquatic environment in the Beijiang River Basin.Based on sentinel-2 MSI multispectral remote sensing data,combined with synchronous data from 59 automatic water quality monitoring stations in the basin,and by analyzing the correlation between TN monitoring data and band combination,this study constructed a random forest TN remote sensing inversion model and analyzed the temporal and spatial variation of TN in the basin from 2019 to 2023.In addition,the land use data from 2019 to 2023 released by the Environmental Systems Research Institute(ESRI)were collected.The Pearson correlation coefficient was used to conduct a single-factor correlation analysis between TN and various land-use types at different spatial scales,and the impact of land-use spatiotemporal change on TN in the watershed was discussed.The prediction effect of the random forest TN remote sensing inversion model was good,R2 was 0.75,root mean square error was 0.42 mg/L,and the model was suitable for the inversion of watershed TN.From 2019 to 2023,the TN concentration in the basin exhibits a downward fluctuating trend.The average concentration of TN was the highest in 2021 and lowest in 2023.The TN concentration increased from the upstream basin to the estuary.The high-value area of TN in the upstream basin was located in the mainstream section,the high-value area of TN in the midstream basin was located in the Changhu reservoir on the Yongjiang River,the high-value area of TN in the downstream basin was located in the Shujiang River section,and the high-value area of the delta basin was located in the Guangzhou section of the Pearl River.The TN concentration was found to have different correlations with different land-use types at different spatial scales.It had significant correlations with agricultural land and grassland at small spatial scales and with forest land and building land at large spatial scales.The proportion of forest land area from the upstream to the downstream basin was the highest,and the proportion of agricultural land area was similar to that of construction land.The delta basin had the highest proportion of construction land,which is much higher than that of forest and agricultural land.From 2019 to 2023,the proportion of agricultural land in the basin decreases annually,the degree of urbanization increased annually,and the source of TN gradually changed from agricultural to domestic and industrial sources.关键词
总氮/水质遥感反演/土地利用/北江流域Key words
Total Nitrogen/water quality remote sensing inversion/land use/Beijiang River Basin分类
资源环境引用本文复制引用
张灵波,周文能,荆文龙,舒思京,杨骥,邓应彬,贾翊文,史兴峰..北江流域总氮遥感反演及其与土地利用关系研究[J].热带地理,2025,45(8):1404-1416,13.基金项目
广东省科技计划项目(2024B1212050010) （2024B1212050010）
2024年广东省海洋经济发展专项(GDNRC[2024]37) （GDNRC[2024]37）
广东省科学院发展专项资金项目(2022GDASZH-2022010111) （2022GDASZH-2022010111）
