OSCAR: Online Service for Correcting Atmosphere in Radar

Tropospheric water vapor content causes delays in radar signals that can alter the phase shifts due to surface deformations or other physical phenomena of interest. In general terms, the accuracy and reliability of interferometric radar data analysis depends on the quality of the correction procedure used to subtract the effect of water vapor on radar signal delays. Data from Global Positioning Systems and infrared radiometers are current used on an ad hoc basis for these corrections when available, and operational weather forecast was demonstrated to be able to fill in the remaining spatial and temporal gaps. OSCAR is a coordinated set of web services that transparently to the user retrieves remote sensing and weather forecast data and delivers atmospheric radar delays on a latitude longitude grid that can be directly integrated with Interferometric Synthetic Aperture Radar data processing software. This tool is currently used by members of the science planning team for DESDynI. We will discuss the architecture of OSCAR, detail the underlying information technology and show concrete examples where water vapor delays were obtained from MODIS infrared data and ECMWF operational weather forecasts.