scholarly journals What determines the maximum sea ice extent in the Sea of Okhotsk? Importance of ocean thermal condition from the Pacific

2010 ◽  
Vol 115 (C12) ◽  
Author(s):  
Takuya Nakanowatari ◽  
Kay I. Ohshima ◽  
Sachiko Nagai
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Thermal Condition ◽  
Sea Ice Extent ◽  
The Sea Of Okhotsk ◽  
The Pacific

scholarly journals Records of sea-ice extent and air temperature at the Sea of Okhotsk from an ice core of Mount Ichinsky, Kamchatka

2011 ◽  
Vol 52 (58) ◽  
pp. 44-50 ◽  
Author(s):  
Sumito Matoba ◽  
Takayuki Shiraiwa ◽  
Akane Tsushima ◽  
Hirotaka Sasaki ◽  
Yaroslav D. Muravyev
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Thermohaline Circulation ◽  
Ice Core ◽  
Solar Irradiation ◽  
Sea Ice Extent ◽  
Arctic Oscillation Index ◽  
High Productivity ◽  
The Sea Of Okhotsk ◽  
Ice Production

AbstarctThe Sea of Okhotsk is the southernmost area in the Northern Hemisphere where seasonal sea ice is produced every year. The formation of sea ice drives thermohaline circulation in the Sea of Okhotsk, and this circulation supports the high productivity in the region. However, recent reports have indicated that sea-ice production in the Sea of Okhotsk is decreasing, raising concern that the decreased sea ice will affect not only circulation but also biological productivity in the sea. To reconstruct climatic changes in the Sea of Okhotsk region, we analyzed an ice core obtained from Ichinskaya Sopka (Mount Ichinsky), Kamchatka. We assumed that the remarkable negative peaks of δD in the ice core were caused by expansion of sea ice in the Sea of Okhotsk. Melt feature percentage (MFP), which indicates summer snowmelt, showed high values in the 1950–60s and the mid-1990s–2000s. The high MFP in the 1950–60s was assumed to be caused by an increase in cyclone activity reaching Kamchatka during a negative period of the Pacific Decadal Oscillation index, and that in the 1990–2000s may reflect the increase in solar irradiation during a positive period of the summer Arctic Oscillation index.

scholarly journals Attributing Causes of 2015 Record Minimum Sea-Ice Extent in the Sea of Okhotsk

2017 ◽  
Vol 30 (12) ◽  
pp. 4693-4703 ◽  
Author(s):  
Seungmok Paik ◽  
Seung-Ki Min ◽  
Yeon-Hee Kim ◽  
Baek-Min Kim ◽  
Hideo Shiogama ◽  
...  
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Coupled Model ◽  
Internal Variability ◽  
Cmip5 Models ◽  
External Forcing ◽  
Sea Ice Extent ◽  
The Sea Of Okhotsk ◽  
The North

In 2015, the sea ice extent (SIE) over the Sea of Okhotsk (Okhotsk SIE) hit a record low since 1979 during February–March, the period when the sea ice extent generally reaches its annual maximum. To quantify the role of anthropogenic influences on the changes observed in Okhotsk SIE, this study employed a fraction of attributable risk (FAR) analysis to compare the probability of occurrence of extreme Okhotsk SIE events and long-term SIE trends using phase 5 of the Coupled Model Intercomparison Project (CMIP5) multimodel simulations performed with and without anthropogenic forcing. It was found that because of anthropogenic influence, both the probability of extreme low Okhotsk SIEs that exceed the 2015 event and the observed long-term trends during 1979–2015 have increased by more than 4 times (FAR = 0.76 to 1). In addition, it is suggested that a strong negative phase of the North Pacific Oscillation (NPO) during midwinter (January–February) 2015 also contributed to the 2015 extreme SIE event. An analysis based on multiple linear regression was conducted to quantify relative contributions of the external forcing (anthropogenic plus natural) and the NPO (internal variability) to the observed SIE changes. About 56.0% and 24.7% of the 2015 SIE anomaly was estimated to be attributable to the external forcing and the strong negative NPO influence, respectively. The external forcing was also found to explain about 86.1% of the observed long-term SIE trend. Further, projections from the CMIP5 models indicate that a sea ice–free condition may occur in the Sea of Okhotsk by the late twenty-first century in some models.

scholarly journals On the growth of ice cover in the Sea of Okhotsk with special reference to its negative correlation with that in the Bering Sea

2005 ◽  
Vol 42 ◽  
pp. 380-388 ◽  
Author(s):  
Kunio Rikiishi ◽  
Shinya Takatsuji
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
Meteorological Data ◽  
Surface Wind ◽  
Ice Cover ◽  
Aleutian Low ◽  
Sea Ice Extent ◽  
The Sea Of Okhotsk ◽  
The Bering Sea

AbstractCharacteristic features of the growth of sea-ice extent in the Sea of Okhotsk are discussed statistically in relation to the surface wind and air temperature over the Okhotsk basin. It is shown that cold-air advection from the continent is not the only factor for the growth of ice extent: air-mass transformation with fetch (downwind distance from the coast) is another important factor. Using weekly growth rates of ice extent and objectively analyzed meteorological data, it is shown that the ice cover extends when cold northerly/northwesterly winds blow, whereas the ice cover retreats when warm northeasterly/easterly winds blow. It is concluded that the advance/retreat of the Sea of Okhotsk ice cover is largely determined by the atmospheric circulation, which is in turn controlled by the position and intensity of the Aleutian low. Occasional out-of-phase fluctuations between the Sea of Okhotsk and Bering Sea ice covers are found to occur when an intensified Aleutian low is located in the mid-western part of the Bering Sea and induces cold northwesterly winds to the Okhotsk basin and warm southeasterly winds to the Bering Sea, or when a weakened Aleutian low is displaced eastward and induces cold northeasterly winds to the Bering Sea and warm northeasterly winds to the Okhotsk basin.

scholarly journals Reassessing seasonal sea ice predictability of the Pacific-Arctic sector using a Markov model

2021 ◽  
Author(s):  
Yunhe Wang ◽  
Xiaojun Yuan ◽  
Haibo Bi ◽  
Mitchell Bushuk ◽  
Yu Liang ◽  
...  
Keyword(s):  
Sea Ice ◽  
Markov Model ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
Regional Model ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
The Sea Of Okhotsk ◽  
The Bering Sea

Abstract. In this study, a regional linear Markov model is developed to assess seasonal sea ice predictability in the Arctic Pacific sector. Unlike an earlier pan-Arctic Markov model that was developed with one set of variables for all seasons, the regional model consists of four seasonal modules with different sets of predictor variables, accommodating seasonally-varying driving processes. A series of sensitivity tests are performed to evaluate the predictive skill in cross-validated experiments and to determine the best model configuration for each season. The prediction skill, as measured by the percentage of grid points with significant correlations (PGS), increased by 75 % in the Bering Sea and 16 % in the Sea of Okhotsk relative to the pan-Arctic model. The regional Markov model's skill is also superior to the skill of an anomaly persistence forecast. Sea ice concentration (SIC) trends significantly contribute to the model skill. However, the model retains skill for detrended sea ice extent predictions up to 6 month lead times in the Bering Sea and the Sea of Okhotsk. We find that surface radiative fluxes contribute to predictability in the cold season and geopotential height and winds play an indispensable role in the warm-season forecast, contrasting to the thermodynamic processes dominating the pan-Arctic predictability. The regional model can also capture the seasonal reemergence of predictability, which is missing in the pan-Arctic model.

Causes and impacts of sea ice variability in the sea of Okhotsk using CESM-LE

2021 ◽  
Author(s):  
Matthew Z. Williams ◽  
Melissa Gervais ◽  
Chris E. Forest
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
The Sea Of Okhotsk
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