Intensification of decadal and multi-decadal sea level variability in the western tropical Pacific during recent decades

• Published in: Climate dynamics Vol. 43; no. 5-6; pp. 1357 - 1379
• Main Authors: Han, Weiqing, Meehl, Gerald A., Hu, Aixue, Alexander, Michael A., Yamagata, Toshio, Yuan, Dongliang, Ishii, Masayoshi, Pegion, Philip, Zheng, Jian, Hamlington, Benjamin D., Quan, Xiao-Wei, Leben, Robert R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2014; Springer; Springer Nature B.V
• Subjects: Climate change; Climatology; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics/Geodesy; Marine; Ocean temperature; Oceanography; Physics of the oceans; Sea level; Sea level rise; Sea surface temperature; Surface waves, tides and sea level. Seiches; Pacific Ocean; Indian Ocean; West Pacific; Equatorial Pacific; ISW, Indian Ocean; IS, Tropical Pacific; IN, North Pacific; Multidecadal; Decadal; Sea level; Pacific decadal variability; Indian Ocean warming; time series analysis; Atmosphere model; General circulation models; Space remote sensing; 1950-2000; Satellite observation; Sea level rise; digital simulation; Ocean model; Measurement in situ; Interdecadal Pacific oscillation; 2000-2010; Observation data; Reanalysis; sea level; Surface wind
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-013-1951-1

Previous studies have linked the rapid sea level rise (SLR) in the western tropical Pacific (WTP) since the early 1990s to the Pacific decadal climate modes, notably the Pacific Decadal Oscillation in the north Pacific or Interdecadal Pacific Oscillation (IPO) considering its basin wide signature. Here, the authors investigate the changing patterns of decadal (10–20 years) and multidecadal (>20 years) sea level variability (global mean SLR removed) in the Pacific associated with the IPO, by analyzing satellite and in situ observations, together with reconstructed and reanalysis products, and performing ocean and atmosphere model experiments. Robust intensification is detected for both decadal and multidecadal sea level variability in the WTP since the early 1990s. The IPO intensity, however, did not increase and thus cannot explain the faster SLR. The observed, accelerated WTP SLR results from the combined effects of Indian Ocean and WTP warming and central-eastern tropical Pacific cooling associated with the IPO cold transition. The warm Indian Ocean acts in concert with the warm WTP and cold central-eastern tropical Pacific to drive intensified easterlies and negative Ekman pumping velocity in western-central tropical Pacific, thereby enhancing the western tropical Pacific SLR. On decadal timescales, the intensified sea level variability since the late 1980s or early 1990s results from the “out of phase” relationship of sea surface temperature anomalies between the Indian and central-eastern tropical Pacific since 1985, which produces “in phase” effects on the WTP sea level variability.