The use of radar altimeter data in combination with other satellite sensors for routine monitoring of the ocean: Case study of the northern Arabian Sea and Gulf of Oman

Abstract

Merged radar altimeter products from TOPEX/POSEIDON and European remote sensing satellite (ERS) have been used to monitor mesoscale ocean features (eddies and fronts) in the Gulf of Oman and northern Arabian Sea. The altimeter data have been compared with coincident thermal infrared and colour images from along-track scanning radiometer (ATSR), advanced very high resolution radiometers (AVHRR), and sea-viewing wide field sensor (SeaWiFS), which provide finer scale detail on fronts and eddies seen in the altimeter data. Time series of data from all of these sources, collected over the period July 1998 to June 1999, reveal that the combination of altimeter and ocean colour data allows tracking of these features in an operationally realistic way. The all-weather altimeter data complement the cloud-limited ocean colour and thermal infrared data. Ocean colour data are especially useful for supporting the indications of mesoscale features provided by the altimeter data. Eddies confirmed using combined data can be tracked during cloudy periods using altimeter data alone. The altimeter is found to perform better in the northern Arabian Sea, where features are larger and less dynamic than in the Gulf of Oman, where ocean features tend to be small, short-lived, and quickly moving.