Estimating the Earth’s Outgoing Longwave Radiation Measured from a Moon-Based Platform

Hanlin Ye,Yiwen Zhang,Jinsong Ping,Huadong Guo,Guang Liu,Lu Zhang

doi:10.3390/rs13112201

Abstract

Moon-based Earth observations have attracted significant attention across many large-scale phenomena. As the only natural satellite of the Earth, and having a stable lunar surface as well as a particular orbit, Moon-based Earth observations allow the Earth to be viewed as a single point. Furthermore, in contrast with artificial satellites, the varied inclination of Moon-based observations can improve angular samplings of specific locations on Earth. However, the potential for estimating the global outgoing longwave radiation (OLR) from the Earth with such a platform has not yet been fully explored. To evaluate the possibility of calculating OLR using specific Earth observation geometry, we constructed a model to estimate Moon-based OLR measurements and investigated the potential of a Moon-based platform to acquire the necessary data to estimate global mean OLR. The primary method of our study is the discretization of the observational scope into various elements and the consequent integration of the OLR of all elements. Our results indicate that a Moon-based platform is suitable for global sampling related to the calculation of global mean OLR. By separating the geometric and anisotropic factors from the measurement calculations, we ensured that measured values include the effects of the Moon-based Earth observation geometry and the anisotropy of the scenes in the observational scope. Although our results indicate that higher measured values can be achieved if the platform is located near the center of the lunar disk, a maximum difference between locations of approximately 9 × 10−4 W m−2 indicates that the effect of location is too small to remarkably improve observation performance of the platform. In conclusion, our analysis demonstrates that a Moon-based platform has the potential to provide continuous, adequate, and long-term data for estimating global mean OLR.

Highlights

The Earth’s outgoing longwave radiation (OLR) refers to the thermal radiation emitted by the Earth-atmosphere system, which is a critical component of the Earth’s radiation budget [1,2,3,4,5,6,7]
We identified the effects of observation geometry on the measurements, and based thereupon, estimated the differences in measurements recorded at different locations on the near side of the
Our study focused on global coverage and OLR measurements estimation based on the Moon-based Earth observation geometry

Summary

Introduction

The Earth’s outgoing longwave radiation (OLR) refers to the thermal radiation emitted by the Earth-atmosphere system, which is a critical component of the Earth’s radiation budget [1,2,3,4,5,6,7]. OLR is predominantly measured at the top of the atmosphere (TOA). Owing to much research effort, space-borne platforms are able to measure OLR at TOA at high accuracy levels [9,10,11]. In the early days of observations, the Earth’s radiation budget, including OLR, was measured by the Nimbus. In the 1980s, the National Aeronautics and Space Administration (NASA) launched new generation Earth Radiation Budget Experiment (ERBE) instruments for measuring OLR [4,13], while, since 1997, the Clouds and the Earth’s Radiant Energy. For a better understanding of the diurnal variation in OLR, the Geostationary Earth Radiation

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Results

Conclusion