The Aquarius Radiometers and Radio Frequency Interference: Analysis of RFI at L-band and its Impact on Salinity Retrieval
[14-Nov-2014] de Matthaeis, P., Kim, S., Soldo, Y., and Le Vine, D.
Presented at the 2014 Aquarius/SAC-D Science Team Meeting
Aquarius is a combined L-band radiometer/scatterometer system designed to map sea surface salinity from space. The salinity retrieval is based on the relationship with brightness temperature, that therefore need to be measured with great accuracy. Although the three Aquarius radiometers operate in the frequency range from 1400 to 1427 MHz that is allocated to passive remote sensing services and radioastronomy, unwanted interference can still be present, both from illegal sources and due to spillover emissions from nearby bands. For this reason, great efforts were made during instrument design to include detection and mitigation of Radio Frequency Interference (RFI) in the Aquarius data processing. As a result, Aquarius has been able to successfully identify RFI and reduce its impact. However, while the most obvious interference has been taken care of, much work remains to be done in order to handle more subtle problems due to undetected RFI and false RFI detection. In this work, some observed changes in regional RFI environments are analyzed with the goal of better understanding the performance of the Aquarius RFI algorithm in particular situations such as when low-level or non-impulsive interference is present. The effect and implications on the salinity retrieval are presented and discussed.