VIIRS/JPSS1 BRDF/Albedo Quality Daily L3 Global 500 m SIN Grid NRT

The VIIRS/JPSS1 BRDF/Albedo Quality Daily L3 Global 500 m SIN Grid Near Real Time (NRT), short-name VJ143IA2N product provides BRDF and Albedo quality at 500 meter (m) resolution. The VJ143IA2N product is produced daily using 16-day VIIRS data (i.e., the current day and the previous 15 days to produce 16-day product).

The algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from VJ143IA1N to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VJ143IA4N), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) (VJ143IA3N). Researchers can use the BRDF model parameters with a simple polynomial, to obtain black-sky albedo at any solar illumination angle. Likewise, both the BSA and WSA Science Dataset (SDS) layers can be used with a simple polynomial, to manually estimate instantaneous actual albedo (blue-sky albedo). Additional details regarding the methodology are available in the Algorithm Theoretical Basis Document (ATBD) at https://www.umb.edu/editor_uploads/images/school_for_the_environment_cs….

The VJ143IA2N data product provides a total of 11 SDS layers including: BRDF/Albedo band quality (inversion information) and days of valid observation within a 16-day period for VIIRS imagery bands I1, I2, and I3, as well as land water type class flag, snow BRDF albedo class flag, local solar noon, and the platform name.

VIIRS/JPSS1 反照率/反照率质量每日 L3 全球 500 米 SIN 网格近实时（NRT）数据产品，简称 VJ143IA2N，提供了 500 米分辨率下的反照率与反照率质量信息。VJ143IA2N 产品每日生成，采用 16 天的 VIIRS 数据（即当前日及前 15 天的数据，以生成 16 天的产品）。算法采用 RossThick/Li-Sparse-Reciprocal（RTLSR）半经验核驱动反照率模型，利用来自 VJ143IA1N 的三个核权重来重建表面各向异性效应，并对方向反射率进行校正，使其符合共同视图几何（VJ143IA4N），同时计算本地正午的黑天空反照率（BSA）（VJ143IA3N）和白云空反照率（WSA）。研究者可以使用 BRDF 模型参数与简单的多项式相结合，以获得任意太阳光照角度下的黑天空反照率。同样，BSA 和 WSA 科学数据集（SDS）层也可以与简单的多项式结合使用，以手动估算瞬时实际反照率（蓝天反照率）。有关方法的详细信息可在算法理论基础文档（ATBD）中找到，文档链接为 https://www.umb.edu/editor_uploads/images/school_for_the_environment_cs…。VJ143IA2N 数据产品共提供 11 个 SDS 层，包括：BRDF/反照率波段质量（反演信息）、16 天周期内 VIIRS 图像波段 I1、I2 和 I3 的有效观测天数、陆地水域类型分类标志、雪面反照率反照率分类标志、本地正午时间以及平台名称。