HOW REGIONAL SEA LEVEL VARIABILITY STUDIES CAN BENEFIT FROM SENTINEL-3

摘要

Sentinel-3 will provide the research on sea levelrnvariability with two key features: 1) high densityrnof repeated tracks and 2) Delay/Doppler processing.rnThis study investigates the benefits from theserntwo features considering previous missions, i.e.rnEnvisat for 1) and Cryosat-2 for 2).rnThe high density of repeated tracks increases therndetection of spatial variation in the sea level variabilityrnat a sub-regional scale. This is evident inrnthe North-Sea/Baltic Sea transition zone, wherernthe ALES coastal reprocessing of Envisat datarnhighlighted significant variations of the annualrnsignal of the sea level in a 50-100 Km scale.rnThe Delay/Doppler processing was already performedrnin the framework of Cryosat-2. The analysisrnof the sea level estimations in the IndonesianrnSeas demonstrates that Cryosat-2 is able torndecrease by roughly 1 cm the high-rate noise ofrnsea level estimation within 50 km of the coast,rnwhen compared to the ALES-reprocessed Envisatrndataset. Despite the fact that the specific groundtracksrnfollowed by Cryosat-2, which repeat everyrn369 days, do not follow the ground-tracks ofrnprevious altimetry missions, no significant changernis seen in the variability if compared to Envisatrnmeasurement. The analysis of the sea surfacernheight anomaly differences between Envisat andrnCryosat-2 at the crossover points proves that in thernregion of study a sea state bias correction equal torn5% of the significant wave height is an acceptablernapproximation for this application.