Observed coastal sea level changes in Southeast Asia from retracked altimetry over 2002-present

Abstract

<p>We present results of contemporary coastal sea level changes along the coasts of different<br>regions of Southeast Asia derived from a dedicated reprocessing of satellite altimetry data.<br>This work is performed in the context of the ESA ‘Climate Change Initiative’ sea level project<br>dedicated to provide altimetry-based sea level time series in the world coastal zones. Here is<br>focus on Southeast Asian Seas. High-frequency (20 Hz) sea level data from the Jason-1,<br>Jason-2 and Jason-3 missions are considered. The data are first retracked using the ALES<br>adaptive leading edge subwaveform retracker and further combined with the X-TRACK<br>processing system developed to optimize the accuracy of the sea level time series in coastal<br>oceans. Rates of sea level change are estimated over the period 2002-present along the Jasontracks,<br>from the open ocean to the coast. Different coastal sea level trend behaviors are<br>observed over the study period: constant trends from open ocean to the coast, sometimes<br>decreasing trends, or increasing trends within the last few km to the coast. We compare the<br>computed coastal trends in Southeast Asia with results we previously obtained in other<br>regions (Mediterranean Sea, Western Africa, Northeastern Europe). We further discuss the<br>various small-scale processes able to explain departure of the coastal sea level rate from the<br>offshore (open ocean) rate.</p>