Water quality change (1988 and 1996) detection by using remote sensing data in several reservoirs of Shenzhen, China

The objective of this research is to explore a precise and fast way of water quality monitor. Water quality change in 1988 and 1996 are detected by remote sensing. One scene TM image in winter of 1996 was acquired and simultaneous in situ measurement, sampling and analysis were performed. Main methods include radiometric calibration of TM remote sensor, atmospheric correction to image data and model construction. The results indicate that satellite-based estimates and in situ measured water reflectance have very high correlation, and the root mean square difference between two kinds of indexes are close to 0.02-0.03 for each TM band in VI-NIR range. Quantity relationship between calibrated image data (average of 5x5 pixels) of TM bands and laboratory analyzed data of water samples indicated reflectance of TM band 1 to band 4 and organic pollution measurements such as TOC, BOD and COD had higher correlation. The same scene TM data in the same season of 1988 was processed in the same procedure. Results indicate water quality of most reservoirs has become worse. Water of eastern reservoirs near Dongjiang River is characterized with higher TOC and TSS, and water of western reservoirs is characterized with higher BOD and COD.The objective of this research is to explore a precise and fast way of water quality monitor. Water quality change in 1988 and 1996 are detected by remote sensing. One scene TM image in winter of 1996 was acquired and simultaneous in situ measurement, sampling and analysis were performed. Main methods include radiometric calibration of TM remote sensor, atmospheric correction to image data and model construction. The results indicate that satellite-based estimates and in situ measured water reflectance have very high correlation, and the root mean square difference between two kinds of indexes are close to 0.02-0.03 for each TM band in VI-NIR range. Quantity relationship between calibrated image data (average of 5x5 pixels) of TM bands and laboratory analyzed data of water samples indicated reflectance of TM band 1 to band 4 and organic pollution measurements such as TOC, BOD and COD had higher correlation. The same scene TM data in the same season of 1988 was processed in the same procedure. Results indicate water quality of most reservoirs has become worse. Water of eastern reservoirs near Dongjiang River is characterized with higher TOC and TSS, and water of western reservoirs is characterized with higher BOD and COD