Challenges and Possibility of Satellite Altimeter Derived Sea Level Anomaly for Tropical Cyclone Identification in the South China Sea: A Preliminary Review

摘要

Continous and synoptic mapping of sea level anomaly (SLA) across the marginal seas is possible thanks to the abundance of altimeter satellite with regulated orbits around the Earth. Though misestimation of satellite derived SLA due to spatial and temporal variation is evident and has led to the significant total bias on the final estimation. The SLA estimation in the South China Sea (SCS) helps in deducing the signature impact of tropical cyclones (TC) in which the TC derived anomalous sea level height can be distinguished. Sparse and small number of tide gauges and buoys available in the SCS limit the spatial and temporal distribution for sea-truth SLA acquisition. This limitation becomes more significant when the single mission satellite data produces SLA data with non-reliable and void pixels. Therefore, this paper is designed to preliminarily review the potentials and challenges of applying satellite altimeter derived SLA from single and multi-mission to deduce the tropical cyclone signature in the SCS. For this study, three altimeter satellite missions namely Jason-1, Envisat-1 and Geosat Follow-On were incorporated to acquire SLA during the severe and energetic TC event Typhoon Chanchu 2006. The results show good agreement of interpolated SLA maps with the TC event nearby at the time of occurrence of SLA variation. This study concludes that multi-mission satellite data has a prominent ability for synoptic mapping the sea level anomaly variation during the tropical cyclone activities in South China Sea.