VIIRS/NPP BRDF/Albedo WSA at Solar Noon Band M4 Daily L3 Global 30ArcSec CMG V002

The NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo white-sky albedo for band M4 (VNP43D70) is produced daily using 16 days of data at 30 arc second (1,000 meter) resolution. Data are temporally weighted to the ninth day, which is reflected in the file name. The VNP43D product suite is provided in a Climate Modeling Grid (CMG), which covers the entire globe for use in climate simulation models. Due to the large file size, each VNP43D product contains just one data layer.

VNP43D54 through VNP43D79 are the albedo products of the VNP43D BRDF/Albedo product suite. Black-sky albedo (BSA) and white-sky albedo (WSA) values are provided for the nine VIIRS moderate resolution bands (M1 through M5, M7, M8, M10, and M11) along with the visible, near-infrared (NIR), and shortwave bands included in the [VNP43MA3](https://doi.org/10.5067/VIIRS/VNP43MA3.002) product. In addition to the bands included in VNP43MA3, this product suite includes albedo values for the VIIRS Day/Night Band (DNB). The black-sky albedo (directional hemispherical reflectance) is defined as albedo in the absence of a diffuse component and is a function of solar zenith angle. White-sky albedo (bihemispherical reflectance) is defined as albedo in the absence of a direct component when the diffuse component is isotropic. Details regarding methodology are available on the [VNP43MA3](https://doi.org/10.5067/VIIRS/VNP43MA3.002) product page and in the Algorithm Theoretical Basis Document (ATBD).

VNP43D70 is the WSA for VIIRS band M4 (0.555 μm).

Known Issues
* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue).

美国国家航空航天局（NASA）与美国国家海洋和大气管理局（NOAA）的苏米国家极轨伙伴卫星（Suomi National Polar-orbiting Partnership, Suomi NPP）搭载的可见光红外成像辐射计套件（Visible Infrared Imaging Radiometer Suite, VIIRS）的双向反射分布函数（Bidirectional Reflectance Distribution Function, BRDF）与反照率产品中，M4波段的晴空反照率（white-sky albedo, WSA）产品（VNP43D70），以16天的观测数据为基础，采用30角秒（约1000米）的分辨率每日生成。数据的时间权重锚定至第9天，该信息将体现在文件名中。VNP43D产品系列采用气候建模网格（Climate Modeling Grid, CMG）进行存储，该网格覆盖全球范围，适配气候模拟模型的使用需求。由于单文件数据量较大，每个VNP43D产品仅包含一个数据图层。

VNP43D54至VNP43D79属于VNP43D BRDF/反照率产品系列的反照率子类产品。该系列为VIIRS的9个中分辨率波段（M1至M5、M7、M8、M10及M11），以及[VNP43MA3](https://doi.org/10.5067/VIIRS/VNP43MA3.002)产品中包含的可见光、近红外（near-infrared, NIR）与短波波段，提供了黑空反照率（black-sky albedo, BSA）与晴空反照率（WSA）数值。除VNP43MA3涵盖的波段外，本产品系列还为VIIRS夜间可见波段（Day/Night Band, DNB）提供了反照率数值。其中，黑空反照率（方向半球反射率）被定义为无漫射分量时的反照率，是太阳天顶角的函数；晴空反照率（双向半球反射率）则被定义为当漫射分量各向同性时，无直射分量时的反照率。相关方法学细节可查阅[VNP43MA3](https://doi.org/10.5067/VIIRS/VNP43MA3.002)产品页面及算法理论基础文档（Algorithm Theoretical Basis Document, ATBD）。

VNP43D70为对应VIIRS M4波段（0.555 μm）的晴空反照率产品。

已知问题
* 如需获取完整的已知问题信息，请参阅[MODIS/VIIRS陆地质量评估网站](https://landweb.modaps.eosdis.nasa.gov/knownissue)