VIIRS/NPP BRDF/Albedo Parameter 1 ShortWave Daily L3 Global 30 ArcSec CMG V001

The VNP43D34 Version 1 data product was decommissioned on July 31, 2025. Users are encouraged to use the [VNP43D34](https://doi.org/10.5067/VIIRS/VNP43D34.002) and [VJ143D34](https://doi.org/10.5067/VIIRS/VJ143D34.002) 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 1 Shortwave product (VNP43D34) 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).

VNP43D34 is the BRDF isotropic parameter for the VIIRS shortwave broadband (1.61 μm). The isotropic parameter, in conjunction with the volumetric and geometric parameters, is used to derive the BRDF/Albedo values for the VIIRS shortwave broadband.

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).

VNP43D34 版本1数据产品已于2025年7月31日正式停用。我们鼓励用户使用[VNP43D34](https://doi.org/10.5067/VIIRS/VNP43D34.002)与[VJ143D34](https://doi.org/10.5067/VIIRS/VJ143D34.002)版本2数据产品。

NASA/NOAA Suomi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）双向反射分布函数（Bidirectional Reflectance Distribution Function, BRDF）与反照率模型参数1短波产品（VNP43D34），每日基于16天的观测数据生成，空间分辨率为30角秒（约1000米）。数据会在时间维度上加权至第9天，该加权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）格式，覆盖全球全域，可用于气候模拟模型。由于单文件体积较大，每个VNP43D产品仅包含单一数据层。针对VIIRS的9个中分辨率波段，以及[VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001)产品中包含的可见光、近红外（Near-Infrared, NIR）和短波波段，其对应的三类模型参数（各向同性、体散射与几何散射）分别以独立文件存储，文件命名为VNP43D01至VNP43D36。除VNP43MA1涵盖的波段外，本产品系列还为VIIRS夜间波段（Day/Night Band, DNB）提供了对应的模型参数，对应文件为VNP43D37至VNP43D39。相关方法学细节可查阅[VNP43MA1](https://doi.org/10.5067/VIIRS/VNP43MA1.001)产品页面，以及算法理论基础文档（Algorithm Theoretical Basis Document, ATBD）。

VNP43D34为VIIRS短波宽带（1.61 μm）对应的BRDF各向同性参数。该各向同性参数与体散射、几何散射参数协同使用，可用于推导VIIRS短波宽带的BRDF与反照率数值。

已知问题
* Collection 1（C1）版本的VNP09产品中，高气溶胶标记出现异常高激活的情况，已对下游产品造成影响。VNP43系列BRDF/反照率/天底BRDF校正反射率（Nadir BRDF-Adjusted Reflectance, NBAR）产品受此影响，表现为用于表征地表各向异性的有效观测样本数量减少。该效应在干旱亮地表区域最为显著，将导致高质量完整BRDF模型反演的数量降低。因此用户需注意，干旱亮地表（通常对应高质量BRDF/反照率/NBAR反演结果）在C1版本中可能呈现出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（需等待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产品中附带的简要强制质量评估（Quality Assurance, QA）数据外，同时下载并使用VNP43[I-M]A2中提供的完整质量评估数据。
* 如需了解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)。