Development of Himawari-8/Advanced Himawari Imager (AHI) Land Surface Temperature Retrieval Algorithm

Youn-Young Choi,Myoung-Seok Suh

doi:10.3390/rs10122013

Youn-Young Choi, Myoung-Seok Suh

Open Access

https://doi.org/10.3390/rs10122013

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Abstract

We developed land surface temperature (LST) retrieval algorithms based on the time of day and water vapor content using the Himawari-8/AHI (Advanced Himawari Imager) data, which is the Japanese next generation geostationary satellite. To develop the LST retrieval algorithms, we simulated the spectral radiance using the radiative transfer model (MODTRAN4) by applying the atmospheric profiles (SeeBor), diurnal variation of LST and air temperature, spectral emissivity of land surface, satellite viewing angle, and spectral response function of Himawari-8/AHI. To retrieve the LST from Himawari-8 data, a linear type of split-window method was used in this study. The Himawari-8 LST algorithms showed a high correlation coefficient (0.996), and a small bias (0.002 K) and root mean square error (RMSE) (1.083 K) between prescribed LSTs and estimated LSTs. However, the accuracy of LST algorithms showed a slightly large RMSE when the lapse rate was larger than 10 K, and the brightness temperature difference was greater than 6 K. The cross-validation of Himawari-8/AHI LST using the MODIS (Terra and Aqua Moderate Resolution Imaging Spectroradiometer) LST showed that annual mean correlation coefficient, bias, and RMSE were 0.94, +0.45 K, and 1.93 K, respectively. The performances of LST algorithms were slightly dependent on the season and time of day, generally better during the night (warm season) than during the day (cold season).

Highlights

Land surface temperature (LST) is affected by the solar zenith angle (SZA), albedo, land cover, soil moisture, and so on [1,2,3], and is an important biophysical parameter of the Earth’s surface that regulates sensible and latent heat fluxes between the surface and the atmosphere
When the viewing zenith angle (VZA) was above 40° and the bbrriigghhttnneessss temperature difference (BTD) was above 8 K, there was a significant increase in the root mean square error (RMSE)
When the VZA was above 40◦ and the BTD was above 8 K, there was a significant increase in the RMSE

Summary

Introduction

Land surface temperature (LST) is affected by the solar zenith angle (SZA), albedo, land cover, soil moisture, and so on [1,2,3], and is an important biophysical parameter of the Earth’s surface that regulates sensible and latent heat fluxes between the surface and the atmosphere. It is important to obtain quantitative and periodic observational LST data for use in a variety of studies, such as those analyzing surface urban heat islands of large cities, making drought predictions for agricultural purposes, and estimating soil moisture [4,5,6,7,8,9]. LST is highly variable, both spatially and temporally, owing to nonuniform surface properties such as vegetation, altitude, and soil moisture, and it is not possible to make in situ observations that are sufficiently accurate and high resolution [10,11]. In Korea, the National Meteorological Satellite Center (NMSC) operationally retrieves LST using the Communication, Ocean, Meteorological Satellite (COMS), which is Korea’s first geostationary multipurpose satellite [30,31,32]

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