Global wave model validation using ENVISAT ASAR wave mode data

Spaceborne active radar remote sensing, e.g., radar altimeter (RA) and synthetic aperture radar (SAR) have been playing an important role in the validation of numerical wave models, particularly in open ocean. Most forecast centres also use altimeter data in the wave data assimilation process. In this paper we present validation results based on the newly developed CWAVE_ENV algorithm. SAR wave mode data have been available since 1991 when ERS-1 was launched. Operational availability, however, began with the ENVISAT Advanced SAR (ASAR) wave mode data. The CWAVE_ENV algorithm yields independent Significant Wave Height (SWH) measurements from the ASAR wave mode data without the need of a priori information. Using the CWAVE algorithm, ASAR data can significantly contribute to global wave monitoring and assimilation. ASAR wave mode data have been processed covering the period from December 2006 to February 2007 using the CWAVE_ENV algorithm. Using both wave height measurements derived from the ASAR wave mode and RA data, we evaluated the performance of the operational DWD ocean wave model, particularly in stormy weather situations.