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Ultra Stable Microwave Radiometers for Future Sea Surface Salinity MissionsThe NASA Earth Science System Pathfinder (ESSP) mission Aquarius will measure global sea surface salinity with 100-km spatial resolution every 8 days with an average monthly salinity accuracy of 0.2 psu (parts per thousand). This requires an L-band low-noise radiometer with the long-term calibration stability of less than 0.1 K over 8 days. This three-year research program on ultra stable radiometers has addressed the radiometer requirements and configuration necessary to achieve this objective for Aquarius and future ocean salinity missions. The system configuration and component performance have been evaluated with radiometer testbeds at both JPL and GSFC. The research has addressed several areas including component characterization as a function of temperature, a procedure for the measurement and correction for radiometer system non-linearity, noise diode calibration versus temperature, low noise amplifier performance over voltage, and temperature control requirements to achieve the required stability. A breadboard radiometer, utilizing microstrip-based technologies, has been built to demonstrate this long-term stability. This report also presents the results of the radiometer test program, a detailed radiometer noise model, and details of the operational switching sequence optimization that can be used to achieve the low noise and stability requirements. Many of the results of this research have been incorporated into the Aquarius radiometer design and will allow this instrument to achieve its goals.
Document ID
20080025042
Acquisition Source
Jet Propulsion Laboratory
Document Type
Preprint (Draft being sent to journal)
External Source(s)
Authors
Wilson, William J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Tanner, Alan B.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Pellerano, Fernando A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Horgan, Kevin A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
April 1, 2005
Subject Category
Oceanography
Report/Patent Number
JPL Report D-31794
Distribution Limits
Public
Copyright
Other
Keywords
sea surface salinity
Aquarius
radiometers
Earth Science System Pathfinder (ESSP)

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