Soil Moisture Mapping
A Combined Approach for Soil Moisture Mapping from a Regional to Global Scale Using Microwave Radiometric Observations and Mathematical Modeling of Soil-Vegetation System
Tech Area / Field
- ENV-MIN/Monitoring and Instrumentation/Environment
- OBS-NAT/Natural Resources and Earth Sciences/Other Basic Sciences
- PHY-RAW/Radiofrequency Waves/Physics
3 Approved without Funding
Russian Academy of Sciences / Institute of Radioengineering and Electronics, Russia, Moscow
- MIRAMAP, The Netherlands, Noordwijk\nInternational Institute for Geo-Inforamation Science and Earth Observation, The Netherlands, Enschede\nUniversità di Roma "La Sapienza" / Dipartimento di Ingegneria Elettronica, Italy, Rome\nCalifornia Institute of Technology / Jet Propulsion Laboratory, USA, CA, Pasadena\nUniversity of Colorado at Boulder / Center for Environmentsl Technology, USA, CO, Boulder\nUnited States Department of the Interior / US Geological Survey / National Wetlands Research Center, USA, LA, Lafayette\nAlabama Agricultural and Mechanical University / Center of Hydrology, Soil Climatology and Remote Sensing, USA, AL, Normal\nPolytechnic University of Catalonia, Spain, Barcelona
A series of world wide large scale Soil Moisture Experiments (SMEX) have been conducted from 1997 – 2005 by the National Aeronautics and Space Administration (NASA) and the United States Department of Agriculture (USDA), ARS, Hydrology and Remote Sensing Laboratory, with the involvement of institutions in the USA, Japan and Brazil. The primary objective of the experiments is to evaluate the capabilities of satellite microwave sensors for soil moisture mapping on a planetary scale. The experiments to date have all utilized a combination of aircraft microwave measurements and in situ measurements to achieve the goal.
Soil moisture was recognized by the NASA Post 2002 Program as a critical measurement. Operational determination of soil moisture spatial-temporal variability plays a leading role in regional and global studies of the Water, Biogeochemical and Energy Cycles. Soil moisture is a key state variable in hydrology: it is the switch that controls the proportion of rainfall that percolates, runs off, or evaporated from the land. It is the life-giving substance for vegetation. Soil moisture integrates precipitation and evaporation over periods of days to weeks and introduces a significant element of memory in the atmosphere-land system. There is strong climatological and modeling evidence that the fast recycling of water through evapotranspiration and precipitation is the primary factor in the persistence of dry or wet anomalies over large continental regions during summer. As a result, soil moisture is possibly one of the most significant land surface boundary conditions controlling the exchange of water and energy with the atmosphere [Soil Moisture Experiments in 2003 (SMEX03). Experiment Plan, June 2003, NASA, USDA-ARS].
In response to the need for soil moisture information, Institute of Radioengineering and Electronics of Russian Academy of Sciences has initiated and developed current SMEX/Russia ISTC Project. We have selected this Project as a continuation of series of SMEX activities and as a part of Earth System Science Pathfinder Program. The efforts will be focused to refine the soil moisture retrieval algorithms, develop robust validation programs and to utilize the current NASA Aqua satellite sensor data for seasonal observations along with microwave and in situ measurements within the selected test sites in European part of Russia and in Siberia.
Thus, the primary objective of this Project is to develop a highly sophisticated Russia calibration and validation input to the series of Soil Moisture Experiments (SMEX). To address this objective and further the science of remote sensing of soil moisture the following science tasks will be accomplished:
- Select representative study areas with typical “soil-vegetation systems” as test-sites for SMEX/Russia Project in the Moscow/Tver’ Region and in Siberia. The areas should be a minimum 50 km x 50 km but could range to 800 km x 800 km. These will include bare soil, steppe agricultural fields, grasslands, wetlands and forested areas with flat and hilly terrain;
- Provide a detailed geographical description of the selected test sites;
- Conduct field experiments to extend the calibration and validation to agricultural crops during different phases of vegetation growth and to forest canopies twice a year in different seasons over a 1 year period;
- Collect field data concurrent with AMSR over passes that will allow the validation of algorithms and definition of the scaling behavior of the measurements in two different seasons over a 1 year period;
- Conduct intercomparisons of radiation data and mean values of soil moisture data at different depths with regard for the type of vegetation cover and amount of biomass;
- Conduct the spectral radiation data modeling using the in situ measurements;
- Define the spectral changes in radiometric data related to changes in soil moisture, vegetation cover and temperature by using experimental observations and the results of modeling.
- Sample typical vegetative canopies and/or plant components to conduct studies of dielectric properties and attenuation by vegetation media using a waveguide transmission system and other methods. It will be shown that the technique chosen provides reliable data on attenuation over a wide frequency band through controlled condition variation of the biometric parameters;
- Combine the remotely sensed data with laboratory tests, in situ measurements and modeling to estimate information about the soil-vegetation system that can be used in hydrology, soil climatology, and water, biogeochemical and energy cycles modeling from a regional to global scales.
This project aims to significantly increase the information content of a “soil-vegetation system” description by developing a multi-parametric approach inherent in the joint use of microwave AMSR-E/Aqua spacecraft data, of ground based microwave data, laboratory tests, in situ measurements and mathematical modeling. Where/when available, the aircraft microwave radiometer data will be used as another source of remotely sensed microwave data input to the system. A range of soil types, soil moisture profiles, hydrological models, plant types and vegetation biomass will be considered. The laboratory measurements of the dielectric properties and attenuation of microwave radiation by plants of different types and biomass will be conducted in this research to take into account the screening effect of vegetation on land surface radiation. Improvements in the vegetation related corrections required in retrieval algorithms are probably the most critical areas of research for increasing the accuracy of soil moisture determination by means of spectral microwave radiometry.
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