Sea level trends in Southeast Asian seas

M. W. Strassburg,B. Nababan,J. Lumban Gaol,K.-Y. Kim,P. Manurung,B. D. Hamlington,S. Vignudelli,R. R. Leben

doi:10.5194/cp-11-743-2015

Abstract

Abstract. Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated with the Pacific Decadal Oscillation and related fluctuations of trade winds in the region. The Southeast Asian sea region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer timescales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past 20 years, the rate of sea level rise is greatly reduced in the Southeast Asian sea region. As a result of the influence of the PDO, the Southeast Asian sea regional sea level trends during the 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the Southeast Asian seas will continue to be affected by GMSL rise occurring now and in the future.

Highlights

Sea level is a measurement of considerable interest and importance for the study of climate because it reflects both mass and heat storage changes in the global ocean
This study focuses on a region of the globe that has been significantly impacted by rising sea levels in the past 2 decades
While projecting future sea level is an expansive problem involving a wide range of disciplines, an understanding of future sea level can be gained by looking at the past

Summary

Introduction

Sea level is a measurement of considerable interest and importance for the study of climate because it reflects both mass and heat storage changes in the global ocean. Sea level has been rising at an increasing rate due to the thermal expansion of water associated with the warming ocean and the melting of land ice (e.g., Church and White, 2011). While the trend in global mean sea level (GMSL) is positive (estimated from satellite altimetry to be 3.2 mm yr−1), the rise of sea level is far from uniform across the globe. Attributing the trends in both regional and global sea level to specific processes has important implications for projecting sea level rise in the future. Internal climate variability on decadal (or longer) timescales can lead

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