Numerical investigations of seasonal and interannual variability of North Pacific Subtropical Mode Water and its implications for Pacific climate variability
Davis, Xujing Jia
Rothstein, Lewis M.
Dewar, William K.
MetadataShow full item record
KeywordSeasonal variability; Interannual variability; North Pacific Ocean; Subtropics; Climate variability; Pacific decadal oscillation
North Pacific Subtropical Mode Water (NPSTMW) is an essential feature of the North Pacific subtropical gyre imparting significant influence on regional SST evolution on seasonal and longer time scales and, as such, is an important component of basin-scale North Pacific climate variability. This study examines the seasonal-to-interannual variability of NPSTMW, the physical processes responsible for this variability, and the connections between NPSTMW and basin-scale climate signals using an eddy-permitting 1979–2006 ocean simulation made available by the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2). The monthly mean seasonal cycle of NPSTMW in the simulation exhibits three distinct phases: (i) formation during November–March, (ii) isolation during March–June, and (iii) dissipation during June–November—each corresponding to significant changes in upper-ocean structure. An interannual signal is also evident in NPSTMW volume and other characteristic properties with volume minima occurring in 1979, 1988, and 1999. This volume variability is correlated with the Pacific decadal oscillation (PDO) with zero time lag. Further analyses demonstrate the connection of NPSTMW to the basin-scale ocean circulation. With this, modulations of upper-ocean structure driven by the varying strength and position of the westerlies as well as the regional air–sea heat flux pattern are seen to contribute to the variability of NPSTMW volume on interannual time scales.
Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 24 (2011): 2648–2665, doi:10.1175/2010JCLI3435.1.
Showing items related by title, author, creator and subject.
Interannual variability of primary production and dissolved organic nitrogen storage in the North Pacific Subtropical Gyre Luo, Ya-Wei; Ducklow, Hugh W.; Friedrichs, Marjorie A. M.; Church, Matthew J.; Karl, David M.; Doney, Scott C. (American Geophysical Union, 2012-08-10)The upper ocean primary production measurements from the Hawaii Ocean Time series (HOT) at Station ALOHA in the North Pacific Subtropical Gyre showed substantial variability over the last two decades. The annual average ...
McKinley, Galen A.; Takahashi, Taro; Buitenhuis, Erik T.; Chai, Fei; Christian, James R.; Doney, Scott C.; Jiang, Mingshun; Lindsay, Keith; Moore, J. Keith; Le Quere, Corinne; Lima, Ivan D.; Murtugudde, Raghu; Shi, L.; Wetzel, P. (American Geophysical Union, 2006-07-04)Climate variability drives significant changes in the physical state of the North Pacific, and thus there may be important impacts of climate variability on the upper ocean carbon balance across the basin. We address this ...
Regional climate variability in the western subtropical North Atlantic during the past two millennia Saenger, Casey P.; Came, Rosemarie E.; Oppo, Delia W.; Keigwin, Lloyd D.; Cohen, Anne L. (American Geophysical Union, 2011-04-21)Western subtropical North Atlantic oceanic and atmospheric circulations connect tropical and subpolar climates. Variations in these circulations can generate regional climate anomalies that are not reflected in Northern ...