scholarly journals Major Driver Leading to Winter SST Variability in the Kuroshio Recirculation Gyre Region and Its Decadal Changes: Refreshening Versus Spring‐Initiated Reemergence Processes

2019 ◽  
Vol 46 (1) ◽  
pp. 272-280 ◽  
Author(s):  
Gyundo Pak ◽  
Sang‐Wook Yeh ◽  
SungHyun Nam ◽  
Young‐Hyang Park ◽  
Young Ho Kim
Keyword(s):  
Sst Variability ◽  
Recirculation Gyre ◽  
The Kuroshio ◽  
Kuroshio Recirculation

scholarly journals Observations of the Subtropical Mode Water Evolution from the Kuroshio Extension System Study

2006 ◽  
Vol 36 (3) ◽  
pp. 457-473 ◽  
Author(s):  
Bo Qiu ◽  
Peter Hacker ◽  
Shuiming Chen ◽  
Kathleen A. Donohue ◽  
D. Randolph Watts ◽  
...  
Keyword(s):  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
Mesoscale Eddy ◽  
Lower Boundary ◽  
Late Winter ◽  
Mode Water ◽  
Subtropical Mode Water ◽  
Budget Analysis ◽  
Recirculation Gyre ◽  
The Kuroshio

Abstract Properties and seasonal evolution of North Pacific Ocean subtropical mode water (STMW) within and south of the Kuroshio Extension recirculation gyre are analyzed from profiling float data and additional hydrographic and shipboard ADCP measurements taken during 2004. The presence of an enhanced recirculation gyre and relatively low mesoscale eddy variability rendered this year favorable for the formation of STMW. Within the recirculation gyre, STMW formed from late-winter convection that reached depths greater than 450 m near the center of the gyre. The lower boundary of STMW, corresponding to σθ ≃ 25.5 kg m−3, was set by the maximum depth of the late-winter mixed layer. Properties within the deep portions of the STMW layer remained largely unchanged as the season progressed. In contrast, the upper boundary of the STMW layer eroded steadily as the seasonal thermocline deepened from late April to August. Vertical eddy diffusivity responsible for this erosion was estimated from a budget analysis of potential vorticity to be in the range of ∼2–5 × 10−4 m2 s−1. The latitudinal extent of the STMW formation was narrow, extending from 30°N to the Kuroshio Extension jet near 35°N. South of 30°N, STMW did not form locally but was transported from the recirculation gyre by lateral induction.

scholarly journals Recent Warming in the Western North Pacific in Relation to Rapid Changes in the Atmospheric Circulation of the Siberian High and Aleutian Low Systems*

2012 ◽  
Vol 25 (10) ◽  
pp. 3476-3493 ◽  
Author(s):  
Young-Hyang Park ◽  
Jong-Hwan Yoon ◽  
Yong-Hoon Youn ◽  
Frédéric Vivier
Keyword(s):  
Wind Stress ◽  
North Pacific ◽  
Western North Pacific ◽  
Rossby Waves ◽  
Delayed Response ◽  
Aleutian Low ◽  
Wind Stress Curl ◽  
Siberian High ◽  
Sst Variability ◽  
The Kuroshio

Abstract On the basis of a new East Asian winter monsoon (EAWM) index and by analyzing the relationship between sea surface temperature (SST) anomalies and different atmospheric and oceanic factors in winter, this study investigates the causes of the recent unusual warming in the western North Pacific Ocean. Analyses presented here emphasize the dual contribution from the atmosphere and ocean to the local SST variability, with the relative importance of each contributor varying with the period and place. During the period 1970–89, the EAWM, controlled mostly by the Siberian high, is predominantly responsible for the SST variability in most of the western North Pacific, whereas in the period 1990–2005 ocean dynamics become increasingly important in most places or even dominant in the Kuroshio–Oyasio Extension (KOE) region. The delayed response of the KOE SST to basinwide wind stress curl forcing via Rossby waves is epoch dependent and is significant at lags of 1, 3, and 4 yr before 1990 but only at 1 yr afterward. This epoch dependency of the impact of Rossby waves is related to the different locations of the centers of action of wind stress curl in the midlatitude North Pacific between the two epochs. In addition, mean advection of the EAWM-driven anomalous SST from the southern East China Sea, which can be transported into the KOE region in about a year by the Kuroshio, likely affects the KOE SST lagged by 1 yr. The strongest positive SST trend observed in the western North Pacific results from the combined effects of the abrupt weakening of the EAWM due to the unprecedented decline of the Siberian high and the increasing role of the ocean. The latter is best evidenced by the 1-yr delayed response of the western North Pacific via the gyre circulation adjustment to the basinwide decadal-scale wind stress curl change associated with the northward shift of the strengthened Aleutian low.

scholarly journals The Kuroshio Extension Northern Recirculation Gyre: Profiling Float Measurements and Forcing Mechanism

2008 ◽  
Vol preprint (2008) ◽  
pp. 1
Author(s):  
Bo Qiu ◽  
Shuiming Chen ◽  
Peter Hacker ◽  
Nelson G. Hogg ◽  
Steven R. Jayne ◽  
...  
Keyword(s):  
Kuroshio Extension ◽  
Profiling Float ◽  
Recirculation Gyre ◽  
The Kuroshio

scholarly journals Investigating the Role of Ocean–Atmosphere Coupling in the North Pacific Ocean

2014 ◽  
Vol 27 (2) ◽  
pp. 592-606 ◽  
Author(s):  
Dimitry Smirnov ◽  
Matthew Newman ◽  
Michael A. Alexander
Keyword(s):  
North Pacific ◽  
Climate Model ◽  
North Pacific Ocean ◽  
Global Climate Model ◽  
The North ◽  
Sst Variability ◽  
Oceanic Forcing ◽  
Noise Forcing ◽  
The Kuroshio ◽  
The North Pacific

Abstract Air–sea interaction over the North Pacific is diagnosed using a simple, local coupled autoregressive model constructed from observed 7-day running-mean sea surface temperature (SST) and 2-m air temperature TA anomalies during the extended winter from the 1° × 1° objectively analyzed air–sea fluxes (OAFlux) dataset. Though the model is constructed from 1-week lag statistics, it successfully reproduces the observed anomaly evolution through lead times of 90 days, allowing an estimation of the relative roles of coupling and internal atmospheric and oceanic forcing upon North Pacific SSTs. It is found that east of the date line, SST variability is maintained by, but has little effect on, TA variability. However, in the Kuroshio–Oyashio confluence and extension region, about half of the SST variability is independent of TA, driven instead by SST noise forcing internal to the ocean. Including surface zonal winds in the analysis does not alter this conclusion, suggesting TA adequately represents the atmosphere. Repeating the analysis with the output of two control simulations from a fully coupled global climate model (GCM) differing only in their ocean resolution yields qualitatively similar results. However, for the simulation employing the coarse-resolution (1°) ocean model, all SST variability depends upon TA, apparently caused by a near absence of ocean-induced noise forcing. Collectively, these results imply that a strong contribution from internal oceanic forcing drives SST variability in the Kuroshio–Oyashio region, which may be used as a justification for atmospheric GCM experiments forced with SST anomalies in that region alone. This conclusion is unaffected by increasing the dimensionality of the model to allow for intrabasin interaction.

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