2012 AGU Chapman Conference on Remote Sensing of the ...

the METRIC (Mapping Evapotranspiration at highResolution using Internalized Calibration) model with andwithout slope-aspect based radiation algorithms and withand without terrain-roughness-related aerodynamicalgorithms to map ET for the study area. METRIC modelpredictions were compared with measurements from BREBSto evaluate generic model accuracy for estimating daily ET.Ishimoto, HiroshiMicrowave Scattering Properties of ComplexShaped SnowflakesIshimoto, Hiroshi 1 ; Aonashi, Kazumasa 11. Meteorological Research Institute, Tsukuba, JapanIn the algorithm of precipitation retrieval by multichannelsatellite microwave radiometer, forward calculationsthat estimate microwave brightness temperatures in thegiven liquid and ice water profiles are crucial. Within someassumptions related to radiative transfer calculations, singlescattering property of snow particles is an important factor.We have investigated the microwave scattering properties ofsnowflakes for the purposes of improving the accuracy offorward calculation in the precipitation retrieval algorithmof the GSMaP (Global Satellite Mapping of PrecipitationProject). Since the shapes of snowflakes are highly complex,simple models of their shapes, such as equivalent volumespheres and soft spheres/spheroids, may cause large errors inestimating ice water contents. In this work, we proposed amodel of complex shaped snowflakes. The modeledsnowflakes were the aggregates of planar crystals and theshape of the crystals were determined from sampled images.Furthermore, the overall shapes and masses of the modeledaggregates were chosen to be consistent with the measuredgeometries of the snowflakes. By using this shape model andusing Finite-Difference Time-Domain (FDTD) method,electromagnetic scattering properties of snowflakes atfrequencies 89GHz and 36GHz were estimated. The resultsof some scattering properties were compared with those ofour previously proposed fractal snowflake models as well asthose of volume equivalent spheres. It is found that ournewly developed snowflake model shows similar sizedependences for scattering cross sections and asymmetryfactors to those of fractal models with fractal dimensions1.8~2.1. For the next step, we are planning to investigate theeffect of ice melting in microwave radiative properties. Anapproach by using numerical simulations of hydrodynamicsfor the deformation of ice particles is briefly discussed.78Numerically created aggregate for a model of snowflakes.Jackson, Thomas J.Advances in the Validation of Satellite SoilMoisture Products with In Situ ObservationsINVITEDJackson, Thomas J. 11. Hydrology & Remote Sensing Lab, USDA ARS, Beltsville,MD, USASatellite-based remote sensing of soil moisture has comea long way in the past decade with regard to providing anaccurate and reliable product. In the early years (1970s) suboptimalsensors designed for other applications were used toexplore the concept without having a planned groundvalidation component. Beginning with the AdvancedMicrowave Scanning Radiometer (AMSR and AMSR-E) in2002, better sensors became available and soil moistureremote sensing was supported as a standard product with adedicated validation program. With the launch of the SoilMoisture Ocean Salinity (SMOS) mission in 2009 and theplanned Soil Moisture Active Passive (SMAP) satellite in2014, we now enter an era of dedicated soil moisturemissions. SMAP, as well as other soil moisture missions, havespecific requirements for validation that include accuracy, aswell as a defined timeline (~15 months after launch forSMAP). One of the most important methodologies availablefor validating satellite soil moisture is data from in situobserving networks. The technology of in situ soil moistureremote sensing has also advanced over the same period thatsatellite sensing progressed. Prior to 2000, the majority ofthe routine measurements available were made using eithergravimetric or neutron probes on an infrequent basis. As aresult of more reliable sensors and improved data acquisitionsystems, the number of in situ soil moisture networksavailable has increased. Satellite missions produce globalproducts; therefore, it is desirable we continue the expansionof the number and geographical distribution of thesenetworks. Unfortunately, these networks have evolvedwithout national or international standardization, which