ADS – A Data and Processing System for Altimetry
Tilo Schoene(1) , Alexander Braun(2) , Saskia Esselborn(1) , and Achim Helm(1)
(2) University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
Several groups on the national and international level are recently active in building up radar altimetry data services to facilitate the access to upgraded and harmonized data to a broader community, especially the access to higher level products. GFZ Potsdam is currently developing the modular German Earth Science and Information System (GESIS). In the frame of GESIS the Altimeter Database System (ADS) has been already developed, implemented, and is being further improved.
The ADS module provides high quality altimeter data for a variety of different altimeter missions and, moreover, processing capabilities for radar altimetry data to a wide range of users. The ADS is an attempt to offer easy access to the daily growing satellite altimetry database and numerous geophysical correction models and orbits. Due to the effectiveness of the underlying data structure and software system, new missions and models can be added to the system at any time. The system has undergone several tests by users successfully and has been proven to be very useful. Especially to users not having convenient access to a satellite altimetry data processing system and a database, ADS offers new possibilities for research.
ADS can be accessed worldwide via the internet based user-interface "ADS Central" with a standard browser at http://gesis.gfz-potsdam.de/ads. After a supervised registration process the system offers higher level standard products, calculated routinely from the harmonized and inter-calibrated satellite database. Additionally, ADS allows generating individual user specific products. The user is able to perform several processing and analyzing steps, e.g. to generate mean sea surface height grids, to extract altimetry data time series around a given location, to analyze parameter variability, or to perform a crossover analysis.
The user can specify general parameters like the time interval or regional subsets and may select different correction models (e.g. tidal models). It is further possible to enter several quality parameters to optimize the data selection for individual applications. These user defined products are automatically processed by ADS at GFZ Potsdam and are subsequently distributed to the user by anonymous FTP.
Currently the use of ADS is offered to selected research groups only. However, the system will easily allow providing a service function capability for future altimetry services.