Ultrastable Radiometer for Sea Surface Salinity Sensing

Quadrant Engineering Inc. (QEI) proposes to develop and characterize an ultrastable microwave radiometer operating at L-band and capable of providing a measurement of sea surface salinity to an accuracy of 0.1-0.1 parts per thousand (ppt). This level of accuracy is necessary to produce useful oceanic data relating to ocean circulation, and requires a radiometer measurement stability precision in the range of 0.05-0.10 K. Based on the performance of existing and similar spaceborne radiometers such as SSM/I and AMSU, we believe that this performance can be achieved. To demonstrate, this study will focus on laboratory development of high precision/high stability front-end architectures and integration of low noise amplifiers, switches, and noise diodes into low loss antenna feeds. In addition, the precision calibration apparatus necessary for long term testing of the radiometer stability will be identified and designed.