We propose to develop and refine the algorithms required for the production and provision of a consistent long-term (1979 to current), global, 1/2 degree, daily, surface Soil Moisture earth system Data Record (SMDR), including uncertainties. This proposal is being submitted to the EOS Algorithm Refinement and Cal/Val for ESDRs subcomponent of the ROSES 2006 A.15 solicitation. This product will be composed of two product elements: The primary product will be based entirely on retrievals from microwave sensors resulting in a validated surface (~0.05m deep) soil moisture focused on croplands and grasslands. These spatial fields of surface soil moisture will be retrieved from microwave brightness temperatures measured from the Scanning Multichannel Microwave Radiometer (SMMR) at 6.63 and 10.69 GHz, the TRMM Microwave Imager (TMI) at 10.65 GHz and from the NASA/Aqua Advanced Microwave Scanning Radiometer (AMSR-E) at 6.7 and 10.65 GHz. The secondary product will be based on the assimilation of microwave radiance from these microwave sensors into a multi-model ensemble, which will result in a root zone (~1m deep) soil moisture data record. These model-integrated products will also provide a pathway for incorporation into coupled earth system prediction models, to improve climate and weather predictions or can be analyzed to provide a better understanding and representation of land-atmosphere processes. A third major activity of the proposed work will be an extensive calibration and validation activity to refine the proposed SMDRs, and to specify their uncertainty. It is well established that remotely-sensed and modeled soil moisture exhibit significant differences. We will therefore attempt to use all available in-situ observations to develop operators that can convert between retrieved, in-situ, and modeled soil moisture. The proposed SMDR will provide an important baseline and algorithm that can be extended with the future NPOESS Conical Scanning Microwave Imager/Sounder (CMIS) and ESA Soil Moisture and Ocean Salinity (SMOS) sensors. Following these steps, we will fully embrace NASA's "missions to measurements" concept by including both EOS and NPOESS sensors in a single integrated soil moisture data record useful for addressing a range of science questions.
