Determining the Role of Vegetation Water Content in L-band Microwave Soil Moisture Monitoring Over the Boreal Forest
Microwave L-band satellite-based SM monitoring is showing excellent potential to provide global SM data. The next step for the validation of L-band SM satellites is to improve the accuracy of SM estimates in forested environments where they are not performing as well. This study focused on two objectives: the evaluation of two approaches for monitoring vegetation water content (VWC) using probes measuring real dielectric constant (RDC) operating at two different frequencies (50 and 70 MHz) and examining how tree RDC impacts the retrieval of SM using radiometers located above and below the boreal forest canopy. The tree RDC probes showed consistency. The below canopy data showed a stronger relationship with the soil RDC. The below canopy data shows an unexpectedly stronger relationship with the tree RDC, suggesting that the boreal forest SM emissivity issues that could be originating from the vegetation are not well represented by stem water monitoring.