Field Radiometric Calibration of a Micro-Spectrometer Based on Remote Sensing of Plateau Inland Water Colors

Abstract

Remote sensing reflectance (Rrs), which is currently measured mainly using the above-water approach, is the most crucial parameter in the remote sensing inversion of plateau inland water colors. It is very difficult to measure the Rrs of plateau inland unmanned areas; thus, we provide a measurement solution using a micro-spectrometer. Currently, commercial micro-spectrometers are not factory calibrated for radiation, and thus, a radiometric calibration of the micro-spectrometer is an essential step. This article uses an Ocean Optics micro-spectrometer (STS-VIS) and a traditional water spectrometer (Trios) to simultaneously measure the irradiance and radiance of diffuse reflectance plates with different reflectance values for field calibration. The results show the following: (1) different fiber types have different calibration coefficients, and the integration time is determined according to the diameter of the fiber and the type of fiber, and (2) by comparing the simultaneous measurement results of STS-VIS with Trios, the mean absolute percentage difference (MAPD) of both reached 18.64% and 5.11% for Qinghai Lake and Golmud River, respectively, which are accurate Rrs measurements of water bodies. The Rrs of the Hoh Xil and Qarhan Salt Lake water bodies in unmanned areas of China was measured, and this was the first collection of in situ spectral information with a micro-spectrometer. This article shows that the micro-spectrometer can perform the in situ measurement of water Rrs in unmanned inland areas. With this breakthrough in the radiometric performance of the micro-spectrometer, we are able to obtain more accurate remote sensing reflectance results of unmanned water bodies.

Special Issue on Remote Sensing Applications in Archaeology, Geography, and the Earth Sciences

“…In the realm of water remote sensing, Li et al [8] presented a simulation method for generating a two-dimensional sea surface current field, aiming to overcome the challenge of limited trajectory crossings in spaceborne SAR data. Shi et al [9] emphasized the significance of remote sensing reflectance as a crucial parameter in the remote sensing inversion of plateau inland water colors. They highlighted the necessity of conducting Field Radiometric Calibration of a Micro-Spectrometer to accurately measure the remote sensing reflectance in unmanned areas of plateau inland regions.…”

A Systematic Review of the Application of GOCI to Water Quality Monitoring of Inland and Coastal Waters

“…Earth's surface water accounts for about 74% of the global area. Water is an important carrier and critical factor in studying the energy exchange of surface materials [1,2]. For research convenience in watercolor remote sensing, the Earth's water is usually divided into Case-I and Case-II waters based on the optical properties of water [3][4][5].…”

A Systematic Review of the Application of the Geostationary Ocean Color Imager to the Water Quality Monitoring of Inland and Coastal Waters

“…Water accounts for about 74% of Earth's surface. Water is an important carrier and critical factor in studying the energy exchange of surface materials [1,2]. For research convenience in water color remote sensing, the Earth's water is usually divided into Case I and Case II waters based on the optical properties of water [3][4][5].…”