GOES-R ABI Land Surface Albedo (LSA) & Surface BRF

Team Members: Jingjing Peng and Peng Yu

Product Description:

The GOES-R ABI Land Surface Albedo (LSA) and Bidirectional Reflectance Factor (BRF) products provide essential information on how Earth land surface reflects solar radiation. Taking advantage of the high temporal resolution of GOES-R observations, the algorithm accumulates multiple angular views within short time windows to retrieve surface BRDF parameters. From these, the following products are generated:

BRDF kernel parameters, which characterize surface anisotropy and support consistent retrievals of albedo and reflectance.
Instantaneous Blue-sky broadband land surface albedo (LSA), representing the fraction of incoming solar radiation reflected by the surface under clear-sky conditions at the observation time stamp.
Spectral BRFs for five ABI channels (0.47, 0.64, 0.86, 1.61, and 2.26 µm), describing directional reflectance at specific wavelengths.
Nadir BRDF-Adjusted Reflectance (NBAR), which normalizes surface reflectance to the nadir-view geometry at local solar noon.

Together, LSA, BRF, NBAR, and BRDF parameters from GOES-east and GOES-west form a consistent, high-frequency dataset that enables continuous monitoring of land surface changes, improves estimates of the surface radiation balance, and supports applications in weather forecasting and ecosystem modeling.

Coverage & cadence

Operational output frequency (GOES-R ABI Mode 6):

Full Disk (FD): every 10 min
CONUS: every 5 min
Mesoscale: every 1 min (per mesoscale scene; 30 s if both scenes coincide).

All at 2 km L2 product resolution.

Theoretical Basis

Joint optimization: A single cost-function inversion estimates BRDF parameters by combining TOA reflectance, variable AOD, and albedo climatology; channels are fit jointly to improve broadband albedo accuracy.
Offline + Online chain:
Offline (end of day): full BRDF inversion from clear-sky multi-time views of that day; results are saved for the next day.
Online (real-time): uses the most recent BRDF (typically within 1 week) to compute LSA; if BRDF is not available, a direct-estimation backup computes LSA from clear-sky TOA reflectance; if still unavailable, albedo climatology is used for graceful fill.
Assumptions: a three-coefficient linear-kernel BRDF; surface anisotropy is stable over a short moving window; reciprocity holds at ABI scale.

Validation:

Albedo (LSA): Compared with SURFRAD, ARM-SGP, and NEON in-situ networks; time-series and statistics show robust agreement, with noted scale effects at heterogeneous sites.
BRF: Evaluated using AERONET-based atmospheric correction; FD and CONUS results show good agreement across channels.