Modification of 6SV to remove skylight reflected at the air-water interface: Application to atmospheric correction of Landsat 8 OLI imagery in inland waters.

Zhaoyi Lu,Fangfang Zhang,Junsheng Li,Shenglei Wang,Hao Zhang,Bing Zhang,Qian Shen,Rashid Ansumana

doi:10.1371/journal.pone.0202883

Zhaoyi Lu, Fangfang Zhang + Show 6 more

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https://doi.org/10.1371/journal.pone.0202883

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Abstract

During the atmospheric correction of remote sensing data in inland waters, the original Second Simulation of the Satellite Signal in the Solar Spectrum-Vector version (6SV) model does not eliminate the specular reflection of downward skylight radiance at the air-water interface. Thus, we propose a modified version of the 6SV model (M6SV) that does remove reflected skylight at the air-water interface. We apply the new model to the atmospheric correction of a Landsat 8 Operational Land Imager (OLI) image over Taihu Lake, China, where the aerosol optical depth is known. In situ reflectance measurements acquired concurrently with the L8/OLI image are used to validate the performance of the new M6SV algorithm. To further analyze the merits and demerits of M6SV, the model is compared with two short-wave infrared (SWIR)-based atmospheric correction models: the Sea-Viewing Wide Field-of-View Sensor Data Analysis System short-wave infrared (SD-SWIR) model and the Vanhellemont & Ruddick short-wave infrared with a per scene fixed aerosol type (VR-SWIR-F) model. Comparisons of results from all three L8/OLI image atmospheric corrections with the in situ remote sensing reflectance data show that M6SV produces reliable atmospheric corrections in the green and red spectral bands and is an effective alternative for Landsat 8 OLI atmospheric correction in inland waters.

Highlights

Satellite remote sensing is a cost-effective way to monitor and quantify optical, biological, and ecological processes and phenomena in inland waters at large and transboundary scales
To obtain the Rrs of each band using the SD-shortwave infrared (SWIR) model, we considered the aerosol type variable over the study area, chose 1609 and 2201 nm for aerosol correction, performed glint correction and cloud masking, and determined aerosol type per pixel
Rrs(561) values over Taihu Lake derived by Chen and Zhang [5, 39,40] are typically greater than 0.03 sr-1; the modified 6SV (M6SV)-derived Rrs(561) and SD-SWIR-derived Rrs(561) values are consistent with this research (Fig 3B and 3J)

Summary

Introduction

Satellite remote sensing is a cost-effective way to monitor and quantify optical, biological, and ecological processes and phenomena in inland waters at large and transboundary scales. Signals reaching a sensor over water contain both the desired water-leaving surface features and undesired atmospheric effects caused by absorption and scattering. Atmospheric correction, the manipulation that can remove such undesired effects from sensor received signals, is a crucial procedure for inland waters quality monitoring [1]. Ocean color sensors, including SeaWiFS (Sea-viewing Wide Field-of-view Sensor, 1997– 2003), MODIS (Moderate-Resolution Imaging Spectroradiometer, 1999–present), MERIS. Modification of 6SV for atmospheric correction over inland waters. 41571361 to Q.S., 41471308 to J.L.).The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

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