Calculation and analysis of 2′×2′ gravity anomalies over the South China Sea based on Cryosat-2 satellite altimeter data

Key words:  satellite altimetry  Cryosat-2  inverse Vening-Meinesz formula  gravity anomaly

Abstract:

The gravity anomaly of the South China Sea was calculated with high spatial resolution and precision using the Cryosat-2 data. The tracks and crossover points of the Cryosat-2 satellite altimetry level 2 SIR_GDR_2A data were analyzed. The component of grid residual vertical deflection was calculated with the weighted minimum least squares solution method using the cycle1-cycle4 data, then the gravity anomalies in 2′×2′ grid over the South China Sea between 4°-24° latitude and 105°-120° longitude were determined. The results show that the Cryosat-2 data have a high track density, and are distributed regularly and uniformly with a 15.9 cm RMS value of crossover point differences, which is slightly higher than the synchronous Jason-2 GDR data. Compared with the post-processed shipboard gravimetry, the root mean square value of the gravity anomaly in 2′×2′ grid over the South China Sea is 4.5×10-5 m·s-2.