Submitted to: IEEE Transactions on Geoscience and Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2011
Publication Date: 1/10/2013
Publication URL: http://handle.nal.usda.gov/10113/56277
Citation: Magagi, R., Berg, A., Goita, K., Belair, S., Jackson, T.J., Toth, B., Walker, A., Mcnairn, H., O'Neil, P.E., Moghaddam, M., Gherboudj, I., Colliander, A., Cosh, M.H. 2013. Canadian experiment for soil moisture in 2010 (CanEx-SM10): Overview and preliminary results. IEEE Transactions on Geoscience and Remote Sensing. 51:347-363. Interpretive Summary: A remote sensing field campaign, the Canadian Experiment for Soil Moisture in 2010 (CanEx-SM10), was conducted to validate the instrument measurements and soil moisture products from the recently launched European Space Agency satellite called Soil Moisture and Ocean Salinity (SMOS). Ground- and aircraft-based measurements were obtained concurrently with satellite observations over two large spatial domains (one cropland and the other forest) located in Saskatchewan Canada in June 2010. Over the agricultural area, the airborne L-band brightness temperatures matched up well with the SMOS data. The temporal evolution of the SMOS soil moisture product matched that observed with ground data, but the absolute soil moisture estimates did not meet the SMOS mission accuracy requirement (0.04 m3/m3). However, it is anticipated that these results will be used by SMOS to refine its retrieval algorithm. The airborne and satellite data acquired, as well as the field measurements and data available from long term soil moisture networks present in the sites will support the validation of SMOS data and products, as well as the pre-launch assessment of the planned (2014) National Aeronautics and Space Administration Soil Moisture Active Passive (SMAP) satellite. SMAP will offer significant improvements in spatial resolution as compared to SMOS and its soil moisture products will support a broader range of agricultural hydrology and crop yield forecasting applications.
Technical Abstract: The Canadian Experiment for Soil Moisture in 2010 (CanEx-SM10) was carried out in Saskatchewan, Canada from 31 May to 16 June, 2010. Its main objective was to contribute to the Soil Moisture and Ocean Salinity (SMOS) mission validation and the pre-launch assessment of the proposed Soil Moisture and Active and Passive (SMAP) mission. During CanEx-SM10, SMOS data as well as other passive and active microwave measurements were collected by both airborne and satellite platforms. Ground-based measurements of soil (moisture, temperature, roughness, bulk density) and vegetation characteristics (Leaf Area Index, biomass, vegetation height) were conducted close in time to the airborne and satellite acquisitions. In addition, two ground-based in situ networks provided continuous measurements of meteorological conditions and soil moisture and soil temperature profiles. Two sites, each covering 33 km x 71 km (about two SMOS pixels) were selected in agricultural and boreal forested areas in order to provide contrasting soil and vegetation conditions. This paper describes the measurement strategy, provides an overview of the data sets, and presents preliminary results. Over the agricultural area, the airborne L-band brightness temperatures matched up well with the SMOS data. The radio frequency interference (RFI) observed in both the SMOS and the airborne L-band radiometer data exhibited spatial and temporal variability and polarization dependency. The temporal evolution of the SMOS soil moisture product matched that observed with ground data, but the absolute soil moisture estimates did not meet the accuracy requirements (0.04 m3/m3) of the SMOS mission. AMSR-E soil moisture estimates are more closely correlated with measured soil moisture.