ACTIVE/PASSIVE MICROWAVE REMOTE SENSING FOR SOIL MOISTURE RETRIEVAL THROUGH A GROWING SEASON

Authors: ONEILL, P - NASA/GSFC; JOSEPH, A - NASA/GSFC; DE LANNOY, G - GW UNIV; LANG, R - GW UNIV; KIM, E - NASA/GSFC; HOUSER, P - NASA/GSFC; Gish, Timothy; Daughtry, Craig

Submitted to: Electromagnetic Wave Interaction with Water and Moist Substances Proceeding
Publication Type: Proceedings
Publication Acceptance Date: 10/3/2002
Publication Date: 5/27/2003
Citation: O'Neill, P., Joseph, A., De Lannoy, G., Lang, R., Kim, E., Houser, P., Gish, T.J., Daughtry, C.S. 2003. Active/Passive microwave remote sensing for soil moisture retrieval through a growing season. In: Proceedings of Electromagnetic Wave Interaction with Water and Moist Substances. p. 342-349.

Interpretive Summary: Given the crucial role that soil moisture plays in most land surface processes, large-scale soil moisture mapping based on microwave remote sensing will be a valuable tool in managing farm operations and predicting crop yields. To take full advantage of these opportunities, however, further development of joint active/passive microwave studies over the full range of changing vegetation conditions typical of a normal growing season is necessary. In this study, the OPE3 site was used and microwave readings were collected over the entire growing season, from planting through harvest. The resulting data set will be used in the development and validation of a coupled dynamic vegetation microwave transfer model for more accurate soil moisture retrievals, and should also provide guidance in designing the most effective instrumentation for a soil moisture space platform mission.

Technical Abstract: An extensive field experiment was conducted from May-early October, 2002 at the heavily instrumented USDA-ARSOPE3 test site to acquire data needed to address active/passive microwave algorithm, modeling, and ground validation issues for accurate soil moisture retrieval. Vegetation cover consisted of a corn crop which was measured from planting through senescence and harvesting. Dual-polarized passive microwave data at 1.4 GHz were recorded continuously throughout the season using the new automated radiometer deployed on a 18-m tower. These microwave measurements were supplemented with weekly dual-frequency (1.6 and 4.75 GHz) quad-polarized radar backscatter data from the truck-mounted radar system. Ground measurements consisting of soil temperature (both physical and infrared), soil moisture (measured gravimetrically, and using portable and in-situ probes), surface roughness, vegetation height and biomass, and vegetation geometry were routinely collected on a daily or weekly basis.