Spring Season Approximation for Earth's Solar-band Radiance at the Moon

This data file presents a simple formulation for approximating Earth's spectral radiance at the Moon, as a function of: 1. Earth's phase angle 2. sub-observer position, i.e. Earth's longitude and latitude from the perspective of a lunar observer, and 3. wavelength This approximation is described in Section 5 of the manuscript by Glenar et al., "Earthshine as an Illumination Source at the Moon" (submitted to Icarus on 2/27/2018.) It was computed by fitting to a grid of NASA Virtual Planetary Laboratory (VPL) models covering Mar-April 2008. This approximation and uncertainties are therefore restricted to spring season, but it is expected the functional form is general enough to extend to other seasons by a simple adjustment of parameter values. A description of the approximation function is included in the data file, along with tabulated parameter values and and the steps needed to compute radiance estimates as a function of wavelength.本数据集文件提供了一种用于近似月球处地球光谱辐亮度的简化公式，其相关自变量包括：1. 地球相位角；2. 亚观测点位置，即从月球观测者视角出发的地球经纬度；3. 波长。该近似方法由Glenar等人在其手稿《Earthshine as an Illumination Source at the Moon》（2018年2月27日提交至《伊卡洛斯（Icarus）》期刊）的第5章节中进行了阐述。本近似公式通过拟合2008年3月至4月期间的美国国家航空航天局（National Aeronautics and Space Administration, NASA）虚拟行星实验室（Virtual Planetary Laboratory, VPL）模型网格计算得到。因此该近似方法及其不确定度仅适用于春季，但通过简单调整参数值，该函数形式具备足够的普适性，可推广至其他季节。本数据集文件中还包含该近似函数的详细说明、制表形式的参数值，以及根据波长计算辐亮度估算值所需的全部步骤。