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

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