scholarly journals Observation of sea-ice thickness fluctuation in the seasonal ice-covered area during 1992−99 winters

2001 ◽  
Vol 33 ◽  
pp. 449-456 ◽  
Author(s):  
Kazutaka Tateyama ◽  
Hiroyuki Enomoto
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
Retrieval Algorithm ◽  
Ice Thickness ◽  
The Sea Of Okhotsk ◽  
Ice Volume ◽  
Fast Ice ◽  
Ice Floes ◽  
The Bering Sea

AbstractSea-ice fluctuations in the Sea of Okhotsk and the Bering Sea during the winters of 1992−99 were investigated by using the Special Sensor Microwave/ Imager dataset and a new ice-property retrieval algorithm This algorithm can distinguish between ice types such as fast ice floes, young ice and new ice, in an area covered by concentrations of >80% ice, and also has improved display resolution because it uses one of the 85 GHz channels. The ice thicknesses derived from the ice-thickness parameter of the new algorithm were compared with ship-based ice-thickness measurements, and were assumed to be 1−10, 11−34, 35−85 and 86−120 cm for new ice, young ice, floes (first-year ice) and fast ice, respectively. The results showed that ice volume can be small even if the ice area is large, due to thinness of the ice (e.g. in 1999 in the Sea of Okhotsk). A significant out-of-phase response, i.e. ice volume is larger in the Sea of Okhotsk when ice volume is smaller in the Bering Sea, was observed. The period of this see-saw showed two different time-scales, which were short (1 week) and long (2−4 weeks).

scholarly journals Study on the Distribution of the Sea Ice over the Sea of Okhotsk and the Bering Sea

2003 ◽  
Vol 108 (0) ◽  
pp. 85-96 ◽  
Author(s):  
Tsugukazu OKUMURA ◽  
Akira FUTAMURA ◽  
Naoto IWASAKA ◽  
Kiyotoshi OTSUKA
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
The Sea Of Okhotsk ◽  
The Bering Sea

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.

scholarly journals Estimation of sea-ice thickness and volume in the Sea of Okhotsk based on ICESat data

2018 ◽  
Vol 59 (76pt2) ◽  
pp. 101-111 ◽  
Author(s):  
Sohey Nihashi ◽  
Nathan T. Kurtz ◽  
Thorsten Markus ◽  
Kay I. Ohshima ◽  
Kazutaka Tateyama ◽  
...  
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Heat Budget ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
The Sea Of Okhotsk ◽  
Ice Volume ◽  
Ice Concentration ◽  
Ice Production ◽  
Hydrostatic Balance

ABSTRACTSea-ice thickness in the Sea of Okhotsk is estimated for 2004–2008 from ICESat derived freeboard under the assumption of hydrostatic balance. Total ice thickness including snow depth (htot) averaged over 2004–2008 is 95 cm. The interannual variability of htot is large; from 77.5 cm (2008) to 110.4 cm (2005). The mode of htot varies from 50–60 cm (2007 and 2008) to 70–80 cm (2005). Ice thickness derived from ICESat data is validated from a comparison with that observed by Electromagnetic Induction Instrument (EM) aboard the icebreaker Soya near Hokkaido, Japan. Annual maps of htot reveal that the spatial distribution of htot is similar every year. Ice volume of 6.3 × 1011 m3 is estimated from the ICESat derived htot and AMSR-E derived ice concentration. A comparison with ice area demonstrates that the ice volume cannot always be represented by the area solely, despite the fact that the area has been used as a proxy of the volume in the Sea of Okhotsk. The ice volume roughly corresponds to that of annual ice production in the major coastal polynyas estimated based on heat budget calculations. This also supports the validity of the estimation of sea-ice thickness and volume using ICESat data.

scholarly journals Sea-ice drift characteristics revealed by measurement of acoustic Doppler current profiler and ice-profiling sonar off Hokkaido in the Sea of Okhotsk

2011 ◽  
Vol 52 (57) ◽  
pp. 1-8 ◽  
Author(s):  
Yasushi Fukamachi ◽  
Kay I. Ohshima ◽  
Yuji Mukai ◽  
Genta Mizuta ◽  
Masaaki Wakatsuchi
Keyword(s):  
Sea Ice ◽  
Sea Of Okhotsk ◽  
Acoustic Doppler Current Profiler ◽  
Ice Thickness ◽  
Coastal Station ◽  
Turning Angle ◽  
The Sea Of Okhotsk ◽  
Ice Drift ◽  
Current Profiler ◽  
Sea Ice Drift

AbstractIn the southwestern part of the Sea of Okhotsk off Hokkaido, sea-ice drift characteristics are investigated using the ice and water velocities obtained from a moored upward-looking acoustic Doppler current profiler (ADCP) during the winters of 1999–2001. Using hourly-mean values of these data along with the wind data measured at a nearby coastal station, the wind factor and turning angle of the relative velocity between the ice and water velocities with respect to the wind are calculated assuming free drift under various conditions. Since the simultaneous sea-ice draft data are also available from a moored ice-profiling sonar (IPS), we examine the dependence of drift characteristics on ice thickness for the first time. As ice thickness increases and wind decreases, the wind factor decreases and the turning angle increases, as predicted by the theory of free drift. This study clearly shows the utility of the moored ADCP measurement for studying sea-ice drift, especially with the simultaneous IPS measurement for ice thickness, which cannot be obtained by other methods.

scholarly journals An Atmospherically Driven Sea-Ice Drift Model for the Bering Sea

1984 ◽  
Vol 5 ◽  
pp. 111-114 ◽  
Author(s):  
C. H. Pease ◽  
J. E. Overland
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Drift Rate ◽  
Sensitivity Study ◽  
Ocean Model ◽  
Ice Thickness ◽  
Drag Coefficients ◽  
Drift Model ◽  
Ice Drift ◽  
The Bering Sea

A free-drift sea-ice model for advection is described which includes an interactive wind-driven ocean for closure. A reduced system of equations is solved economically by a simple iteration on the water stress. The performance of the model is examined through a sensitivity study considering ice thickness, Ekman-layer scaling, wind speed, and drag coefficients. A case study is also presented where the model is driven by measured winds and the resulting drift rate compared to measured ice-drift rate for a three-day period during March 1981 at about 80 km inside the boundary of the open pack ice in the Bering Sea. The advective model is shown to be sensitive to certain assumptions. Increasing the scaling parameter A for the Ekman depth in the ocean model from 0.3 to 0.4 causes a 10 to 15% reduction in ice speed but only a slight decrease in rotation angle (α) with respect to the wind. Modeled α is strongly a function of ice thickness, while speed is not very sensitive to thickness. Ice speed is sensitive to assumptions about drag coefficients for the upper (CA) and lower (CW) surfaces of the ice. Specifying CA and the ratio of CA to CW are important to the calculations.

scholarly journals A Study of the Fluctuations in Sea-Ice Extent of the Bering and Okhotsk Seas with Passive Microwave Satellite Observations (Abstract)

1987 ◽  
Vol 9 ◽  
pp. 236-236
Author(s):  
D.J. Cavalieri ◽  
C.L. Parkinson
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
Large Scale ◽  
Phase Relationship ◽  
Kamchatka Peninsula ◽  
Sea Ice Extent ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
The Bering Sea

The seasonal sea-ice cover of the combined Bering and Okhotsk Seas at the time of maximum ice extent is almost 2 × 106 km2 and exceeds that of any other seasonal sea-ice zone in the Northern Hemisphere. Although both seas are relatively shallow bodies of water overlying continental shelf regions, there are important geographical differences. The Sea of Okhotsk is almost totally enclosed, being bounded to the north and west by Siberia and Sakhalin Island, and to the east by Kamchatka Peninsula. In contrast, the Bering Sea is the third-largest semi-enclosed sea in the world, with a surface area of 2.3 × 106 km2, and is bounded to the west by Kamchatka Peninsula, to the east by the Alaskan coast, and to the south by the Aleutian Islands arc.While the relationship between the regional oceanography and meteorology and the sea-ice covers of both the Bering Sea and Sea of Okhotsk have been studied individually, relatively little attention has been given to the occasional out-of-phase relationship between the fluctuations in the sea-ice extent of these two large seas. In this study, we present 3 day averaged sea-ice extent data obtained from the Nimbus-5 Electrically Scanning Microwave Radiometer (ESMR-5) for the four winters for which ESMR-5 data were available, 1973 through 1976, and document those periods for which there is an out-of-phase relationship in the fluctuations of the ice cover between the Bering Sea and the Sea of Okhotsk. Further, mean sea-level pressure data are also analyzed and compared with the time series of sea-ice extent data to provide a basis for determining possible associations between the episodes of out-of-phase fluctuations and atmospheric circulation patterns.Previous work by Campbell and others (1981) using sea-ice concentrations also derived from ESMR-5 data noted this out-of-phase relationship between the two ice packs in 1973 and 1976. The authors commented that the out-of-phase relationship is “... surprising as these are adjacent seas, and one would assume that they had similar meteorologic environments”. We argue here that the out-of-phase relationship is consistent with large-scale atmospheric circulation patterns, since the two seas span a range of longitude of about 60°, corresponding to a half wavelength of a zonal wave-number 3, and hence are quite susceptible to changes in the amplitude and phase of large-scale atmospheric waves.

Lycodapus (Pisces: Zoarcidae) of eastern Bering Sea and nearby Pacific Ocean, with three new species and a revised key to the species

1981 ◽  
Vol 59 (4) ◽  
pp. 667-678 ◽  
Author(s):  
Alex E. Peden ◽  
M. Eric Anderson
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Bering Sea ◽  
Sea Of Okhotsk ◽  
Range Limit ◽  
The Sea Of Okhotsk ◽  
Eastern Bering Sea ◽  
Northern Range Limit ◽  
Three New Species ◽  
The Bering Sea

Lycodapus leptus n.sp., L. poecilus n.sp., and L. psarostomatus n.sp. are described from the eastern Bering Sea. A new key to all known species of Lycodapus is presented. In addition, L. fierasfer Gilbert, L. parviceps Gilbert, and L. derjugini Andriashev are recognized from the Bering Sea and L. microdon Schmidt is recognized from the Sea of Okhotsk. The northern range limit of Lycodapus dermatinus Gilbert is established from a sea mount off southeastern Alaska. A specimen of Lycodapus that cannot be identified to species represents the most southern record for the genus in Asiatic waters.

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