Interbasin effects of the Indian Ocean on Pacific decadal climate change. Issue 13 (13th July 2016)

• Record Type: Journal Article
• Authors: Mochizuki, Takashi; Kimoto, Masahide; Watanabe, Masahiro; Chikamoto, Yoshimitsu; Ishii, Masayoshi
• Is Part Of: Geophysical research letters. Volume 43:Issue 13(2016)
• Page Start: 7168
• Page End: 7175
• Publication Date: 2016-07-13
• Subjects: interbasin connection -- decadal climate variability -- pacemaker experiment -- data assimilation -- Indian Ocean warming -- global warming; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL069940
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We demonstrate the significant impact of the Indian Ocean on the Pacific climate on decadal timescales by comparing two sets of data assimilation experiments (pacemaker experiments) conducted over recent decades. For the Indian Ocean of an atmosphere‐ocean coupled global climate model, we assimilate ocean temperature and salinity anomalies defined as deviations from climatology or as anomalies with the area‐averaged changes for the Indian Ocean subtracted. When decadal sea surface temperature (SST) trends are observed to be strong over the Indian Ocean, the equatorial thermocline uniformly deepens, and the model simulates the eastward tendencies of surface wind aloft. Surface winds strongly converge around the maritime continent, and the associated strengthening of the Walker circulation suppresses an increasing trend in the equatorial Pacific SST through ocean thermocline shoaling, similar to common changes associated with seasonal Indian Ocean warming. Key Points: We perform the so‐called pacemaker experiments by assimilating the ocean observations over the Indian Ocean to a global climate model The basin‐averaged ocean variability of the Indian Ocean significantly modulates the Pacific decadal trend on decadal timescales The associated Walker circulation change dynamically yields interbasin contrast in trends of the equatorial Indian and Pacific Oceans