Passive/Active L/S-band Aircraft Microwave Sensor for Ocean Salinity Measurements
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Modern microwave radiometers have demonstrated the feasibility of monitoring surface salinity from space and also the need for better accuracy in cold water. Accuracy could be improved by adding measurements at lower frequencies (lower than the measurement at 1.4 GHz currently used) and closer to the peak in sensitivity of brightness temperature to changes in salinity. Proposals to accomplish this have focused on wide bandwidth receivers which include at the low end frequencies close to the peak in sensitivity. This strategy involves trade-offs, some obvious such as radio frequency interference (RFI) when operating outside the protected band at 1.4 GHz and the loss of spatial resolution at lower frequencies. Others stemming from the interdependence of the retrieval of salinity on water temperature and surface roughness are more subtle. The objective of this manuscript is to examine this interdependence and its implications to future wide bandwidth instruments for remote sensing of salinity from space.
A concept has been studied for remote sensing of sea surface salinity and soil moistute from space using a large deployable mesh antenna system.
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The product of a working group assembled to help define the science objectives and measurement requirements of a spaceborne L-band microwave radiometer devoted to remote sensing of surface soil moisture and sea surface salinity is presented. Remote sensing in this long-wavelength portion of the microwave spectrum requires large antennas in low-Earth orbit to achieve acceptable spatial resolution. The proposed radiometer, ESTAR, is unique in that it employs aperture synthesis to reduce the antenna area requirements for a space system.
An NEDT analysis of a Dicke radiometer with noise diode injenction is presented.
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No abstract available
This paper will present the results of the radiometer test program and details on the design of the Aquarius radiometer. the operational sequence that will be used to achieve the low noise and stability requirements will also be discussed.
A concept has been studied for remote sensing of sea surface salinity form space using a large deployable mesh antenna system.