Location: Hydrology and Remote Sensing Laboratory
Project Number: 8042-13610-029-94-I
Project Type: Interagency Reimbursable Agreement
Start Date: Mar 23, 2015
End Date: Mar 31, 2017
The objective of this project is to resolve the Aquarius satellite warm bias in brightness temperatures calibration, adapt the current algorithm as new versions of the brightness temperature are developed, and provide a routine soil moisture product for hydrologic and climate application. Aquarius (NASA Satellite) observations over land offer an unprecedented opportunity to provide new measurements from space of surface soil moisture, which will contribute to a better understanding of the Earth’s climate and water cycle. This agreement focuses on the further development and implementation of a soil moisture product using Aquarius/SAC-D (Scientific Application Satellite-D) observations. The basis of this product was established in the preceding project. In that investigation it was discovered that Aquarius brightness temperatures needed to be calibrated for the full dynamic range from ocean to land observations. The results provided strong evidence of warm bias in the Aquarius brightness temperature calibration over land. This warm bias results in inconsistencies in the relative calibrations of Aquarius and other satellite brightness temperature observations. As a result, this issue must be resolved before a final soil moisture product can be provided. The Aquarius products will be valuable to the validation of the future NASA Soil Moisture Active Passive satellite.
The baseline soil moisture algorithm will be implemented as part of the routine processing of Aquarius data. Validation studies will be conducted using in situ observations and soil moisture products from other satellites. In conjunction with the soil moisture analyses, the causes of the warm bias in brightness temperature will be investigated with the Aquarius team. As new versions of the Aquarius data are provided, parameterizations utilized in the soil moisture algorithm will be updated. ARS will work with the NASA data archival center to provide soil moisture to its wide-ranging users involved in modeling and analyses of hydrologic and climate processes and applications. Analysis of Aquarius observations over land will contribute to establishing a longer term climate record of L-band brightness temperature and soil moisture when combined with future missions such as the Soil Moisture Active Passive satellite.