Near real time processing and validation of T/P and ERS-2 altimeter data (DUACS project)

Abstract

This chapter discusses the near real-time processing and validation of T/P and ERS-2 altimeter data, developing the use of altimeter data for climate studies (DUACS). The goal of the DUACS EC project was to develop and validate a Near Real Time (NRT) altimeter data processing system for climate and seasonal prediction studies. Altimeter data from TOPEX/POSEIDON Interim Geophysical Data Record (IGDR) and ERS-2 Fast Delivery Products (FDP) are fully processed, combined, and validated every week. They are delivered, at the earliest, 2 days after the last gathered measurement. Altimeter products consist of a long-track sea level anomaly (SLA) data and the maps of SLA. After a roughly 2 month delay imposed by the processing and distribution of the best available delayed time homogenous historical (HH) data from TOPEX/POSEIDON and ERS-2, the NRT SLA data are compared to HH SLA data. The NRT SLA data has a very good accuracy with respect to HH data. NRT data can, thus, be used to monitor large scale climatic signals, such as El Nino, with accuracy on the order of 2 cm root mean square (RMS). It can also provide an accurate fine-scale description of different current systems and of the mesoscale variability.