Project Number: 1265-13610-027-53
Project Type: Reimbursable

Start Date: Sep 01, 2006
End Date: Aug 31, 2009

Objective:
Future satellite remote sensing missions currently rely on baseline soil moisture retrieval algorithms developed over grasslands, agricultural crops and light to moderate vegetation; tree areas have generally been excluded from operational soil moisture retrieval plans. This investigation would provide information on the microwave properties of trees and their impact on soil moisture retrieval algorithms and fill a major gap in our knowledge base.

Approach:
The research study proposed here will include both theoretical examination of microwave emission/scattering effects from trees and a multisensor measurement program using an active/passive microwave truck-mounted instrument system, visible/infrared sensors and airborne lidar to begin to address how to handle soil moisture retrieval through small stands of deciduous and coniferous trees. Data will be acquired over soil moisture drydown cycles at different times of the year to quantify the seasonal microwave response to soil moisture through tree (in particular, the effect of fall/winter leaf drop on soil moisture retrieval accuracy). The resulting analysis should provide an improved understanding of the accuracy levels of soil moisture retrievals possible through different tree stands and whether the existing retrieval algorithms need modification (in terms of form or effective parameterization). Eventually, the knowledge gained here will help to extend the SMOS/Hydros soil moisture retrievals to more areas globally than currently planned.