SMAP-based retrieval of vegetation opacity and albedo

TL;DR

This study uses SMAP satellite data to analyze how vegetation affects microwave signals across various biomes, focusing on transparency, seasonal changes, scattering, and the impact on soil condition retrieval.

Contribution

It provides new insights into vegetation microwave properties and their influence on microwave remote sensing across different biomes using SMAP data.

Findings

Vegetation canopy transparency varies across biomes at L-band.

Seasonal amplitude of vegetation microwave optical depth differs among biomes.

Effective scattering properties of vegetation influence microwave signal interpretation.

Abstract

Over land the vegetation canopy affects the microwave brightness temperature by emission, scattering and attenuation of surface soil emission. The questions addressed in this study are: 1) what is the transparency of the vegetation canopy for different biomes around the Globe at the low-frequency L-band?, 2) what is the seasonal amplitude of vegetation microwave optical depth for different biomes?, 3) what is the effective scattering at this frequency for different vegetation types?, 4) what is the impact of imprecise characterization of vegetation microwave properties on retrieval of soil surface conditions? These questions are addressed based on the recently completed one full annual cycle measurements by the NASA Soil Moisture Active Passive (SMAP) measurements.