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

Authors: O'NEILL, P. - NASA/GSFC; JOSEPH, A. - NASA/GSFC; KIM, E. - NASA/GSFC; LANG, R. - GEORGE WASHINGTON UNIV; HOUSER, P. - NASA/GSFC; Gish, Timothy; Daughtry, Craig

Submitted to: Electromagnetic Wave Interaction with Water and Moist Substances Proceeding
Publication Type: Abstract Only
Publication Acceptance Date: 10/3/2002
Publication Date: 5/3/2003
Citation: O'Neill, P., Joseph, A., Kim, E., Lang, R., Houser, P., Gish, T., Daughtry, C.S.T. 2003. Active/Passive microwave remote sensing for soil moisture retrieval through a growing season. In: Proceedings of the 5th International Conference on Electromagnetic Wave Interaction with Water and Moist Substances, March 24-26, 2003, Rotorua, New Zealand 2003 CDROM.

Interpretive Summary:

Technical Abstract: Given the crucial role that soil moisture plays in most land surface processes, large-scale soil moisture mapping based on microwave remote sensing would be valuable in many different practical and theoretical applications, and a real potential exists for new space missions in the near future which will utilize simultaneous active/passive microwave measurements for global soil moisture retrieval. To take full advantage of these opportunities, however, further development of joint active/passive microwave retrieval algorithms is necessary, especially over the full range of changing vegetation conditions typical of a normal growing season. Vegetation cover consisted of a corn crop which was measured from planting through senescence at the USDA, OPE3 site, located in Beltsville, MD. Dual-polarized passive microwave data at 1.4 GHz were recorded continuously throughout the season using the new automated NASA / GSFC Lrad instrument deployed on a 60-ft tower. These microwave measurements were supplemented with weekly dual-frequency (1.6 and 4.75 GHz) quad-polarized radar backscatter data from the NASA-GSFC / GWU truck-mounted radar system. Ground measurements consisting of soil temperature (both physical and infrared), soil moisture (measured gravimetrically, volumetrically, and theta probes), surface roughness, vegetation height and biomass, and vegetation geometry were routinely collected on a daily or weekly basis. Additionally, standard observations of surface meteorology, surface energy balance, soil properties, and hydrological variables. 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 provide guidance in designing the most effective instrumentation for a soil moisture mission.