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Summary of Proposal LAN1575

TitleMulti-frequency SAR for soil moisture retrieval
Investigator McNairn, Heather - Canadian Federal Government, Agriculture and Agri-Food Canada
Team Member
Research Scientist McNairn, Heather - Government of Canada, Agriculture and Agri-Food Canada
Associate Professor Berg, Aaron - University of Guelph, Geography
Professor Bullock, Paul - University of Manitoba, Soil Science
Physical Scientist a ONeill, Peggy - NASA Goddard Space Flight Center, Hydrological Sciences Branch
Physical Scientist Joseph, Alicia - NASA Goddard Space Flight Center, Hydrological Sciences Branch
Professor Magagi, Ramata - Universite de Sherbrooke, Geomatique appliquee
Research Hydrologist Cosh, Michael - United States Department of Agriculture, Agricultural Research Service
Professor Moghaddam, Mahta - University of Southern California, Electrical Engineering
Research Scientist Kim, Seungbum - Jet Propulsion Laboratory/California Institute of Technology, Science Division
SummarySoil moisture is a critical variable in agricultural productivity, hydrological cycling and weather forecasting. This information need is confirmed by NASA’s commitment to launch the Soil Moisture Active Passive (SMAP) satellite in 2014. Active SAR sensors have a critical role to play in providing data to support modeling of the microwave signal through crop vegetation, and in downscaling passive microwave data. In addition, these active sensors provide the sub-field level soil moisture not attainable using passive microwave technology. In 2012, a team of 75 Canadian and U.S. scientists participated in the SMAPVEX12 experiment in southern Manitoba (Canada). An extensive field data set was collected, along with 16 flights of NASA’s UAVSAR and PALS instruments. RADARSAT-2 acquired data throughout the campaign and 15TerraSAR-X images were programmed. The Manitoba site is one of the Canadian JECAM sites and this proposal is to request access to the 2012 TerraSAR-X data and to request the collection of a validation data set in 2013. The research team will examine the sensitivity of X-Band data to soil moisture. In addition the data will be used to assess how multi-frequency SAR data can provide information products of use to the agriculture community, but also required for evaluation of the SMAP soil moisture algorithm. These products include information on the crop canopy (type,biomass, water content) to support accurate estimation of attenuation of the microwave signal by the vegetation. The project will develop crop information products as well as an evaluation of TerraSAR-X for soil moisture estimation. Beyond these products, outputs will also include presentations and publications highlighting the value of TerraSAR-X for agriculture applications. The SMAPVEX experiment was funded by internal agency resources, as well as by the Canadian Space Agency (CSA) and NASA. CSA funding to Canadian participants in SMAPVEX continues until March 2014.
Final ReportDetails of the SMAPVEX12 experiment can be found in the following publication: McNairn, H., Jackson, T.J, Wiseman, G., Bélair, S., Berg, A., Bullock, P.R., Colliander, A., Cosh, M.H, Kim, S., Magagi, R., Moghaddam, M., Adams, J.R., Homayouni, S., Ojo, E.R., Rowlandson, T., Shang, J., Goïta, K., Hosseini, M. The Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12): Pre-Launch Calibration and Validation of the SMAP Satellite. IEEE Transactions on Geoscience and Remote Sensing, vol.53, no.5, pp.2784-2801, May 2015 doi: 10.1109/TGRS.2014.2364913 The TerraSAR-X data usage has been primarily focused on the use of the X-band data from crop condition and crop phenology determination. Knowledge of crop phenology is important for many agronomic applications including timing of fertilizer and pesticide applications, yield estimation and harvest prediction, as but a few examples. The Canadian team (AAFC and A.U.G. Signals) has been interested in the use of X and C-band data for phenology determination to assist with determining crop disease risk. Specifically, canola (an important export crop for Canada) is susceptible to a range of diseases which can significantly impact production. Given the acreages of canola planted in Canada, early assessment of risk is paramount to assist with optimal application of fungicides and insecticides. Risk is linked closely with farming practices, meteorological conditions, soil moisture and crop phenology. AAFC is working with A.U.G. signals to examine both TerraSAR-X and RADARSAT-2 to determine if these sensors can differentiate canola growth stages. Results to date suggest that SAR parameters responsive to volume scattering, vary from one growth stage to the next. Specifically, changes in the X-Band VV/VH ratio and several C-Band parameters (VV/VH ratio, volume/surface ratio and alpha angle) have been observed when canola flowers and begins seed/pod development. These growth stages are important in determining risk and mitigation for sclerotinia stem rot and insect infestation. A.U.G. and AAFC now have a co-funded project to further develop a data mining algorithm to use X and C-band data to determine flowering in canola, as well as other important growth stages for wheat, corn and canola.

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