Validation of jason-2 and ENVISAT wind speed and significant wave height data in the intertropical zone

Abstract

The estimates of significant wave height (SWH) and wind speed at 10 meter height (u10) from the Jason-2 and ENVISAT satellites, over the intertropical region, are analysed. Some authors have tested the dependency of satellite radar wind/wave measurements on local environmental conditions, particularly on wave age, with no conclusive results. Our data show that Jason-2 overestimates high values of SWH and underestimates low values, while ENVISAT exhibits the opposite behaviour. The correlation coefficient between buoy measurements and altimeter data is around 0.95, with bias and root mean square error (RMSE) of, 3 and 15 cm respectively. On the other hand, Jason-2 underestimates u10 throughout the whole measured range, while ENVISAT overestimates throughout the whole range for speeds over 3 m/s. The correlation coefficient is around 0.90, with bias and RMSE around 0.20 cm and 1.5 m/s, respectively. The altimeter estimates in the intertropical region are similar to those obtained with global coverage, hence the sensitivity to sea state to extract wind speed and wave height is not so obvious in our data set. Therefore, the results indicate that the algorithms employed have a fair enough performance in the intertropical region. © 2013 Sociedade Brasileira de Geofísica.