caa a22 4500 467946949 CHVBK 20180405193738.0 cr unu---uuuuu 170328e20041001xx s 000 0 eng 10.1007/s10872-005-5779-0 doi (NATIONALLICENCE)springer-10.1007/s10872-005-5779-0 (NATIONALLICENCE)springer-10.1007/s10872-004-5779-5 Interdecadal temperature variations in the North Pacific Central Mode Water simulated by an OGCM [Elektronische Daten] [Shigeki Hosoda, Shang-Ping Xie, Kensuke Takeuchi, Masami Nonaka] The North Pacific Central Mode Water (CMW) is a water mass that forms in the Kuroshio-Oyashio Extension (KOE) region with characteristic low potential vorticity. Recent studies have suggested that the CMW, as low potential vorticity water, plays an important role in the adjustment of the subtropical gyre and subsurface variability on decadal to interdecadal timescales. We have forced a realistic ocean general circulation model (OGCM) with observed wind stress and sea surface temperature (SST) forcing to investigate the decadal variations of the CMW. Associated with the large atmospheric changes after the mid-1970s climate regime shift, the upper thermocline experiences a cooling as negative SST anomalies in the central North Pacific are subducted and advected southward. In addition to this thermodynamic response, the CMW's path shifts anomalously eastward in response to anomalous Ekman pumping. This eastward shift of the core of the CMW produces a lowering of the isotherms, and a consequent warming, on the path of the CMW core. This warming partially counteracts the cooling associated with subducted surface anomalies, and it may be responsible for the reduced temperature variations at the climatological position of the CMW when both anomalous wind and heat fluxes are given. Lateral induction across the sloping bottom of the winter mixed layer in the KOE is critical to the formation of the low potential vorticity CMW. Coarse resolution models, which are widely used in climate modeling, underestimate the horizontal gradient of the mixed layer depth and form only a weak CMW or none at all. We have conducted a coarse resolution experiment with the same OGCM, showing that the subsurface response is much reduced. In particular, there is no dynamic warming in the CMW and the thermodynamic response to the SST cooling dominates. The resultant total response differs substantially from that in the finer resolution run where a strong CMW forms. This sensitivity to the model resolution corroborates the important dynamical role that the CMW may play with its distinctive low potential vorticity character and calls for its improved simulation. The Oceanographic Society of Japan, 2004 Decadal variability nationallicence OGCM nationallicence Central Mode Water nationallicence simulation nationallicence Hosoda Shigeki Japan Marine Science and Technology Center, Natsushima-cho, 237-0061, Yokosuka, Japan aut Xie Shang-Ping International Pacific Research Center and Department of Meteorology, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, USA aut Takeuchi Kensuke Frontier Observational Research System for Global Change, Natsushima-cho, 237-0061, Yokosuka, Japan aut Nonaka Masami International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, USA aut Journal of Oceanography Kluwer Academic Publishers 60/5(2004-10-01), 865-877 0916-8370 60:5<865 2004 60 10872 https://doi.org/10.1007/s10872-005-5779-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10872-005-5779-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xie Shang-Ping International Pacific Research Center and Department of Meteorology, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, USA aut NATIONALLICENCE 700 1- Nonaka Masami International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, USA aut NATIONALLICENCE 700 1- Hosoda Shigeki Japan Marine Science and Technology Center, Natsushima-cho, 237-0061, Yokosuka, Japan aut NATIONALLICENCE 700 1- Takeuchi Kensuke Frontier Observational Research System for Global Change, Natsushima-cho, 237-0061, Yokosuka, Japan aut NATIONALLICENCE 773 0- Journal of Oceanography Kluwer Academic Publishers 60/5(2004-10-01), 865-877 0916-8370 60:5<865 2004 60 10872 NATIONALLICENCE 856 40 https://doi.org/10.1007/s10872-004-5779-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nonaka Masami International Pacific Research Center and Department of Meteorology, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, U.S.A aut NATIONALLICENCE 700 1- Xie Shang-Ping International Pacific Research Center and Department of Meteorology, School of Ocean and Earth Science and Technology, University of Hawaii, 96822, Honolulu, HI, U.S.A aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE NATIONALLICENCE NL-springer