Patterns of Indian Ocean Sea-Level Change in a Warming Climate

• Main Authors: Han, Weiqing, Meehl, Gerald A., Rajagopalan, Balaji, Fasullo, John T., Hu, Aixue, Lin, Jialin, Large, William G., Wang, Jih-wang, Quan, Xiao-Wei, Trenary, Laurie L.
• Other Authors: NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
• Format: Text
• Language: English
• Published: 2010
• Subjects: Atmospheric Physics; Meteorology; Physical and Dynamic Oceanography; Geodesy; *OCEAN CURRENTS; *INDIAN OCEAN; *SEA LEVEL; *OCEAN MODELS; *WIND; *GREENHOUSE EFFECT; MELTING; CLIMATE; ALTIMETERS; SEA ICE; BENGAL BAY; ROSSBY WAVES; BANGLADESH; ZANZIBAR; SATELLITE IMAGERY; THERMAL EXPANSION; FRESH WATER; TIME SERIES ANALYSIS; GRAPHS; IN SITU ANALYSIS; INDIA; REPRINTS; HADLEY CELLS; WALKER CELLS; GREENHOUSE GASES; HYCOM(HYBRID COORDINATE OCEAN MODEL); POP(PARALLEL OCEAN PROGRAM); AGCM(ATMOSPHERIC GENERAL CIRCULATION MODELS); NCAR(NATIONAL CENTER FOR ATMOSPHERIC RESEARCH); ICOADS(INTERNATIONAL COMPREHENSIVE OCEAN ATMOSPHERE DATA SET); SLA(SEA LEVEL ANOMALIES); KENDALL THEIL TRENDS; SST(SEA SURFACE TEMPERATURE); MALDIVES; PE0602435N; 73-8677-10-5; Indian; Kendall; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA540559; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA540559

Global sea level has risen during the past decades as a result of thermal expansion of the warming ocean and freshwater addition from melting continental ice. However, sea-level rise is not globally uniform. Regional sea levels can be affected by changes in atmospheric or oceanic circulation. As long-term observational records are scarce, regional changes in sea level in the Indian Ocean are poorly constrained. Yet estimates of future sea-level changes are essential for effective risk assessment. Here we combine in situ and satellite observations of Indian Ocean sea level with climate-model simulations, to identify a distinct spatial pattern of sea-level rise since the 1960s. We find that sea level has decreased substantially in the south tropical Indian Ocean whereas it has increased elsewhere. This pattern is driven by changing surface winds associated with a combined invigoration of the Indian Ocean Hadley and Walker cells, patterns of atmospheric overturning circulation in the north-south and east-west direction, respectively, which is partly attributable to rising levels of atmospheric greenhouse gases. We conclude that--if ongoing anthropogenic warming dominates natural variability--the pattern we detected is likely to persist and to increase the environmental stress on some coasts and islands in the Indian Ocean. Published in Nature Geoscience, v3 p546-550, Aug 2010. Sponsored in part by NASA, NSF (OCE-0847605) and DoE (DE-FC02-97ER62402).