Publications

Song, T; Gong, SQ; Liu, JZ; Gu, ZF; Shi, JZ; Wu, W (2018). Performance Assessment of Atmospheric Correction for Multispectral Data of GF-4 on Inland Case II Turbid Water. SPECTROSCOPY AND SPECTRAL ANALYSIS, 38(4), 1191-1197.

Abstract
GF-4 satellite is the first geostationary satellite with high spatial resolution in China, which has great potential in the aspects of inland water monitoring. This paper takes the Taihu Lake as study area to evaluate the accuracy of GF-4 derived spectral reflectance after atmospheric correction, aiming to provide valuable information for the application of GF-4 data to water color remote sensing. The MODIS-aided improved Gordon atmospheric correction algorithm was used to conduct atmospheric correction for GF-4 images obtained on 2016-07-21 and 2016-08-17. In situ measurements of quasi-synchronous samples and atmospheric corrected GOCI (Geostationary Ocean Color Imager) data were used to validate the GF-4 derived spectral reflectance. The results show that the red-light B4 band had the highest accuracy with RMSE (Root Mean Square Error) of 1.25 X 10(-3) and MAPE (Mean Absolute Percentage Error) of 10.71%, the green-light B3 band had RMSE of 2.43 X 10-3 and MAPE of 13.21%, and the near-infrared B5 band had RMSE of 1.95 X 10(-3) and MAPE of 33.06%. The blue-light B2 band had the worst accuracy with RMSE of 6.81 X 10(-3) and MAPE of 53.55%. The accuracy of B3, B4 and B5 bands of GF-4 were higher than those of GOCI. This is because that the spatial resolution of GF-4 is much higher than that of GOCI, so the errors caused by mixed pixel were relatively smaller, showing the advantage of GF-4 as a high-resolution geostationary satellite when used in water color remote sensing. The accuracy of B2 band of GF-4 was lower than that of GOCI, indicating the B2 band of GF-4 still has room for improvement. In the future, the B2 band should be corrected separately, and the usage of this band in water color remote sensing should be avoided if it is not corrected properly. Overall, the multispectral data of GF-4 has relatively high accuracy and can used to monitor the inland case II turbidwater. In order to improve the accuracy of GF-4 derived spectral reflectance, several researches should be conducted in the future. First, aerosol observation stations should be established to obtained long-term data needed by the multiple scattering algorithm forlocalaerosol. Second, the study area should be divided into several subregions in order to reduce the errors caused by the assumption that the air condition was the same for the whole study area. The third, the spatial resolution of GF-4 was 50 m, while the effective area of thespectrograph probe was only 1 m(2). Spectrum data should be collected at multiple points within one GF-4 pixel, so that the errors caused by scale mismatch can be reduced.

DOI:
10.3964/j.issn.1000-0593(2018)04-1191-07

ISSN:
1000-0593