The Effect of Land Contamination and Radiofrequency Interference on the Aquarius Coastal Salinity: The East China Sea
[13-Nov-2013] Kim, S., Lee, J., Hong, C., Pang, I., de Matthaeis, P., and Yueh, S.
Presented at the 2013 Aquarius/SAC-D Science Team Meeting
This paper assesses the quality of the Aquarius salinity product over the East China Sea in the presence of land and RFI (radiofrequency interference) contaminations on the salinity retrieval. The marginal sea is adjacent to land mass to the three sides of the sea, and is next to strong sources of RFI. To examine the sensitivity of the salinity retrieval on the land correction approach, two models for simulating the land emission were compared. Over land, the outputs of these two models differ by more than 20 K. However, away from the coastline towards the sea by about one Aquarius radiometer pixel (~150 km), the difference becomes smaller than 0.1 K, which would be equivalent to about 0.2 psu uncertainty. The Aquarius standard salinity retrieval was compared with in situ observations taken at mostly 0.5 m depth over three locations in 2011 and 2012. The mean biases are -0.005, -0.36, and -0.77 psu. Low-level RFI may not have been detected and removed by the RFI filter that was applied to the standard Aquarius product, which may explain the negative bias. The retrieved salinity correlates with the river discharge rate over one and a half year period with the coefficient of 0.74. These comparison results indicate that the monitoring of salinity by the Aquarius instrument in the marginal sea is feasible despite the two contaminants.