Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Sensors (Basel). 2022 Feb 17;22(4):1581. doi: 10.3390/s22041581.
Moon-based Earth radiation observation can provide longer-term, continuous multi-angle measurements for the Earth's outward radiative flux. In addition, the large distance between the Moon and Earth means that the radiation can be monitored by a non-scanning Moon-based Wide Field-of-View (MWFOV) radiometer considering the Earth as one pixel. In order to parameterize the radiometer, studying the effect of the temporal sampling interval on irradiance is of great importance. In this work, based on radiation transfer model, simulated irradiance time series from March 2000 to December 2020 were analyzed. Then, we used them to reveal the effects of the sampling interval on irradiance. The results show that the measurements of the MWFOV radiometer can reveal the variation of irradiance on hourly, daily and monthly time scales, and the high-frequency measurements can reflect the variation of scene types in the MWFOV-viewed area. In order to obtain more meaningful measurements, the radiation resolution of the MWFOV radiometer should be better than 0.5mW∙m with an accuracy of 1% or better in the future actual design, and the sampling interval should be less than 1 h, which can ensure that 97% of the surface area can be sampled more than nine times per day for longwave radiation. The derived results in this study could facilitate Moon-based data processing and the determination of the sampling interval and radiation resolution of an MWFOV under a certain manufacturing cost and error limit.
基于月球的地球辐射观测可以提供地球向外辐射通量的长期、连续多角度测量。此外，月球与地球之间的大距离意味着可以通过非扫描基于月球的宽视场（MWFOV）辐射计来监测辐射，将地球视为一个像素。为了对辐射计进行参数化，研究时间采样间隔对辐照度的影响非常重要。在这项工作中，基于辐射传输模型，分析了 2000 年 3 月至 2020 年 12 月的辐照度时间序列的模拟数据。然后，我们使用这些数据来揭示采样间隔对辐照度的影响。结果表明，MWFOV 辐射计的测量可以揭示辐照度在小时、日和月时间尺度上的变化，高频测量可以反映 MWFOV 视场内场景类型的变化。为了获得更有意义的测量结果，MWFOV 辐射计的辐射分辨率在未来的实际设计中应优于 0.5mW·m，精度优于 1%，采样间隔应小于 1 小时，这可以确保 97%的表面积每天可进行超过九次的长波辐射采样。本研究得出的结果可以为基于月球的数据处理以及在一定制造成本和误差限制下确定 MWFOV 的采样间隔和辐射分辨率提供便利。
