The influence of lunar surface position on irradiance of moonbased earth radiation observation

As a platform for longer-term continuous moon-based earth radiation observation(MERO)which includes reflected solar short-wave(SW)radiation and long-wave infrared(LW)radiation,the huge lunar surface space can provide multiple location choices.It is important to analyze the influence of lunar surface position on irradiance which is the aim of the present work based on a radiation heat transfer model.To compare the differences caused by positions,the site of 0°E 0°N was selected as the reference site and a good agreement of the calculation results was verified by the comparison with the NISTAR’s actual detected data.By analyzing the spatial characteristics of the irradiance,the results showed that the irradiance on the lunar surface was of circular distribution and the instrument that was placed in the region of 65°W-65°E and 65°S-65°N could detect the irradiance most effectively.The relative deviation between the reference site and the marginal area(region of>65°S or 65°N or>65°W or 65°E)was less than 0.9 mW∙m^(-2) and the small regional differences make a small-scale network conducive to radiometric calibration between instruments.To achieve accurate measurement of the irradiance,the sensitivity design goal of the MERO instrument should be better than 1 mW∙m^(-2) in a future actual design.Because the lunar polar region is the priority region for future exploration,the irradiance at the poles has also been analyzed.The results show that the irradiance changes periodically and exhibits complementary characteristics of time.The variation range of irradiance for short-wave radiation is greater than longwave radiation and the irradiance of SW reaches the maximum at different times.The MERO at the polar region will provide valuable practical experiment for the followup study of the moon-based earth observation in low latitudes.