The Study Of Water Color Inversion Model In Fujian Province Based On HJ-1 A/B CCD And HSI Data

Based on the HJ-1 satellite data,the inversion model of water color parameters is developed.This can provide technical basis to monitor the chlorophyll a and suspension dynamically and continuously in Fujian province.The main contents and conclusions are summarized as follows:(1)The automatic water extraction and atmospheric correction.Based on the segment of automatic NDWI threshold,the water information is extracted widely.The confusion is removed by OSTU threshold,spectral and geometric feature.This method can quickly extract large water body information,but the small water body information is leaked.Based on the single-scattering theory of Gordon,the atmospheric correction for Xiamen Sea is completed assisted by MODIS data.The atmospheric correction for Xiamen Sea is also completed with FLAASH.Compared with the measured Rrs of water,the Rrs of FLAASH is bigger than the measured Rrs,but its ratio is close to the measured Rrs’s.However the Rrs of Gordon is close to the measured Rrs,its ratio is deviated from the measured Rrs’s.(2)The establishment and validation of chlorophyll-a and suspended sediment inversion model.With the spectral response of HJ-1 CCD,the correlation analysis between the measured Rrs of water and measured chlorophyll-a concentration is done.Then the inversion model of 10-inedx based on B1/B2 is built.Its correlation coefficient is 0.8147.The effect of different atmospheric correction method for the 10-index model’s precision is evaluated.The precision of 10-index model is bad for the HJ-1 CCD data corrected atmospherically with Gordon single-scattering theory.Then a new model based on the B2 and B3/B4 is built.It is reasonable to choose the atmospheric correction model whish’s Rrs is close to the measured Rrs.With the historical spectral reflectance and suspended sediment concentration,the inversion model of suspended sediment based on the B3/B1 for Xiamen Sea is fitted,the correlation coefficient is 0.506.(3)The study for half-analysis model of chlorophyll a and suspend sediment.With multiband analysis model,the linear inversion model of chlorophyll a based on B2/B1 and suspended sediment based on B3/B2 is built.The model can extract the distribution information of water color parameters for Xiamen Sea.With three-band model of Gordon,the most relevant three-band factor with the measured chlorophyll a concentration for the measured water spectrum is:663.01 nm,701.86nm,740.7nm.The most relevant three-band factor for HSI data is:669.28 nm,711.49 nm,732.01 nm.(4)The adaptability validation of inversion model in Fujian province.With the measured chlorophyll a concentration,the adaptability of OC3 model,10-index model,half-analysis model is validated.The adaptability of half-analysis model is the best.The OC3 model’s adaptability is better than the 10-index model’s.With the measured suspended sediment,the adaptability of experience model based B3/B2 and half-analysis model based on B3/B1 is validated.The experience model’s adaptability is better than half-analysis model’s.The inversion system of water color parameters is built in order to meet the commercial needs.