VIIRS/NPP BRDF/Albedo Parameter 2 Band M7 Daily L3 Global 30 ArcSec CMG V001

The VNP43D17 Version 1 data product was decommissioned on July 31, 2025. Users are encouraged to use the [VNP43D17](https://doi.org/10.5067/VIIRS/VNP43D17.002) and [VJ143D17](https://doi.org/10.5067/VIIRS/VJ143D17.002) Version 2 data products.

The NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo Model Parameter 2 Band M7 product (VNP43D17) 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. Each of the three model parameters (isotropic, volumetric, and geometric) for each of the nine VIIRS moderate resolution bands along with the visible, near-infrared (NIR), and shortwave bands included in the [VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001) product is stored in a separate file as VNP43D01 through VNP43D36. In addition to the bands included in VNP43MA1, this product suite includes model parameters for the VIIRS Day/Night Band (DNB) as VNP43D37 through VNP43D39. Details regarding methodology are available on the [VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001) product page and in the Algorithm Theoretical Basis Document (ATBD).

VNP43D17 is the BRDF volumetric parameter for VIIRS band M7 (0.865 μm). The volumetric parameter, in conjunction with the isotropic and geometric parameters, is used to derive the BRDF/Albedo values for VIIRS band M7.

Known Issues
* The abnormally high activation of the high aerosol flag in the Collection 1 (C1) VNP09 product has impacted downstream products. The VNP43 BRDF/Albedo/NBAR product is affected by reducing the number of otherwise acceptable observations used as input to characterize surface anisotropy. This effect (most obvious over arid bright surfaces), results in a reduced number of high quality full BRDF model inversions. Therefore, users should be aware that bright arid surfaces (normally associated with high quality BRDF/Albedo/NBAR retrievals) are likely to be somewhat represented by lower quality results in C1. VNP09 has been corrected for Collection 2 (C2). Therefore, users should avoid substantive use of C1 VNP43 over arid regions (and wait for C2 products). In any event, users are **always strongly encouraged** to download and use the extensive QA data provided in VNP43[I-M]A2, in addition to the briefer mandatory QA provided as part of the VNP43[I-M]A1, 3 and 4 products.
* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS).

VNP43D17 版本1数据产品已于2025年7月31日正式退役。鼓励用户使用[VNP43D17](https://doi.org/10.5067/VIIRS/VNP43D17.002)与[VJ143D17](https://doi.org/10.5067/VIIRS/VJ143D17.002)版本2数据产品。

NASA与NOAA合作的Suomi国家极轨伙伴卫星（Suomi National Polar-orbiting Partnership, Suomi NPP）可见光红外成像辐射计套件（Visible Infrared Imaging Radiometer Suite, VIIRS）双向反射分布函数（Bidirectional Reflectance Distribution Function, BRDF）与反照率模型参数2波段M7产品（VNP43D17），采用16天的观测数据每日生成，空间分辨率为30角秒（约1000米）。数据以第9天为时间加权中心，该信息将体现在文件名中。VNP43系列产品采用气候建模网格（Climate Modeling Grid, CMG）格式，可覆盖全球范围，适配气候模拟模型的使用需求。由于单文件体积较大，每个VNP43系列产品仅包含一个数据层。针对[VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001)产品中涵盖的9个VIIRS中分辨率波段、可见光波段、近红外（Near-infrared, NIR）以及短波波段，其三类模型参数（各向同性、体散射、几何散射）分别以VNP43D01至VNP43D36的命名存储于独立文件中。除VNP43MA1包含的波段外，该系列产品还为VIIRS昼夜波段（Day/Night Band, DNB）提供了对应模型参数，对应文件为VNP43D37至VNP43D39。相关方法学细节可参阅[VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001)产品页面及算法理论基础文档（Algorithm Theoretical Basis Document, ATBD）。

VNP43D17为VIIRS M7波段（0.865 μm）的BRDF体散射参数。该体散射参数与各向同性参数、几何散射参数结合，可用于推导VIIRS M7波段的BRDF与反照率数值。

### 已知问题
* Collection 1（C1）版本的VNP09产品中，高气溶胶标志出现异常高激活的情况，对下游产品造成了影响。VNP43系列BRDF/反照率/归一化双向反射率（NBAR）产品受到波及，用于表征地表各向异性的有效观测数量被削减，该影响在干旱亮地表区域最为显著，最终导致高质量完整BRDF模型反演的数量降低。因此，用户需注意：原本可获得高质量BRDF/反照率/NBAR反演结果的干旱亮地表区域，在C1版本中可能呈现为较低质量的反演结果。VNP09产品已在Collection 2（C2）版本中完成修正，因此用户应避免在干旱区域大量使用C1版本的VNP43系列产品（建议等待C2版本产品）。无论何种情况，**强烈建议**用户除使用VNP43[I-M]A1、3和4产品中附带的简短强制质量评估（Quality Assurance, QA）数据外，一并下载并使用VNP43[I-M]A2中提供的详细质量评估数据。
* 如需获取已知问题的完整信息，请参阅[MODIS/VIIRS陆地质量评估网站](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS)。