Analysis and Prediction of Short-Term Ice Drift

1988 ◽  
Vol 110 (1) ◽  
pp. 94-100 ◽  
Author(s):  
M. G. McPhee
Keyword(s):  
Boundary Layer ◽  
Bering Sea ◽  
Similarity Theory ◽  
Physical Processes ◽  
Motion Modeling ◽  
Short Term ◽  
Complex Demodulation ◽  
Ice Drift ◽  
Boundary Layer Dynamics ◽  
The Bering Sea

Techniques for kinematic analysis and dynamic, “free-drift” ice modeling are described and applied to interpretation of ice-drift data from recent marginal ice zone (MIZ) experiments. Kinematic description is based on a complex demodulation algorithm that separates inertial and tidal components from lower frequency, “synoptic” drift. Complex demodulation produces the time series of phasors (complex numbers describing phase and amplitude of the oscillating components), useful for separating the physical processes active in the upper ocean/ice system. Free-drift ice motion modeling utilizes a similarity theory for planetary-boundary-layer dynamics that includes the effect of buoyancy, both from rapid melting at the ice/ocean interface, and/or from a pre-existing density gradient (pycnocline) within the boundary layer. Two examples are considered: one in which a band of ice in the Bering Sea drifted rapidly away from the rest of the pack when it encountered warm water at the ice edge; and a second in which drift in the Greenland Sea was apparently affected by both a shallow pycnocline and a period of rapid melt.

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 Role of physical processes in formation of spring phytoplankton bloom in the Bering Sea

Trudy VNIRO ◽  
2020 ◽  
Vol 181 ◽  
pp. 206-222
Author(s):  
K.K. Kivva ◽  
◽  
J.V. Selivanova ◽  
M.N. Pisareva ◽  
A.A. Sumkina ◽  
...  
Keyword(s):  
Bering Sea ◽  
Phytoplankton Bloom ◽  
Physical Processes ◽  
Spring Phytoplankton Bloom ◽  
Eastern Bering Sea ◽  
Ice Retreat ◽  
Shelf Region ◽  
Sea Ice Retreat ◽  
Bering Sea Shelf ◽  
The Bering Sea

The main part of the annual primary production in the Arctic and Subarctic zones of the World Ocean is formed during the spring phytoplankton bloom. The timing of the bloom depends on combination of physical factors. Oscillating control hypothesis, proposed in [Hunt et al., 2002] for the Eastern Bering Sea, describes annual peculiarities of ecosystem development related to conditions of the spring phytoplankton bloom. We review propositions of this hypothesis on the reasons of phytoplankton bloom and its connection with physical processes for four local regions of the Bering Sea shelf. The regions include western, northern and south-eastern parts of the shelf. The analysis is based on ocean color and microwave remotely sensed data as well as on atmospheric reanalysis. The results allow for hypothesis improvement. An early phytoplankton bloom may be present in the surface layer in April or May along the eastern Bering Sea shelf even in situations of early sea ice retreat (e. g. February-March) or absence of ice during winter. However, such combinations were not observed in the western Bering Sea shelf region. In 1998–2018, early ice retreat in the western shelf region was always accompanied by relatively late phytoplankton bloom. The temporal lag between sea ice retreat and phytoplankton bloom may be substantial in some years along the southernmost position of the ice edge. On the other hand, the spring bloom in the northern part of the shelf usually follows the ice retreat. In case of early ice retreat, the timing of the bloom is determined not only by wind conditions, but also by heat balance at the surface of the sea. The results are proposed to be used in further analysis of ecosystem dynamics of the western Bering Sea shelf.

Tidal energy fluxes and bottom boundary layer energy dissipation in the Bering Sea

2010 ◽  
Vol 9 (3) ◽  
pp. 340-346 ◽  
Author(s):  
Pei-liang Li ◽  
Juan Zhou ◽  
Lei Li ◽  
Wei Zhao ◽  
Chang-lin Chen
Keyword(s):  
Boundary Layer ◽  
Energy Dissipation ◽  
Bering Sea ◽  
Tidal Energy ◽  
Bottom Boundary Layer ◽  
Energy Fluxes ◽  
Bottom Boundary ◽  
The Bering Sea

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 On the role of ocean circulation in seasonal and interannual ice-edge variations in the Bering Sea

1991 ◽  
Vol 15 ◽  
pp. 37-44 ◽  
Author(s):  
Jinlun Zhang ◽  
William D. Hibler
Keyword(s):  
Boundary Layer ◽  
Ocean Circulation ◽  
Bering Sea ◽  
Ocean Model ◽  
Vertical Diffusion ◽  
Northwestern Shelf ◽  
Ice Edge ◽  
Oceanic Boundary Layer ◽  
Bering Sea Shelf ◽  
The Bering Sea

A 40 km-resolution ice—ocean model of the Bering Sea is used to investigate the effects of ocean circulation and vertical convection on the seasonal and interannual ice extent variations in the Bering Sea. The model is driven with daily time-varying atmospheric forcing from 1981–83. A series of sensitivity studies is carried out to examine the effects of the vertical diffusion and precipitation on the ice margin and the effect of stratification on the ocean circulation. For comparison, an ice-only simulation, with a motionless oceanic boundary layer of fixed depth, is also carried out. In the Aleutian Basin, the ice-ocean model exhibits a cyclonic ocean circulation which consists mainly of a baroclinic current component. On the eastern Bering Sea shelf the flow is mainly barotropic, with a northwestern shelf flow along the Alaskan coast and a return southeastern flow along the shelf break. The seasonal and interannual variability of the ice margin is significantly better simulated by the ice-ocean model than by the ice-only model, especially when an enhanced vertical diffusion is used. However, the seasonal cycle of ice extent exhibits too little ice in the southeastern Bering Sea and excessive ice in the northwest. The advance and retreat of the ice edge also tends to lag behind the observed results by a few weeks. The inclusion of precipitation improves the ice extent in the southeast. The results suggest that an enhanced vertical resolution, together with a more complete boundary layer formulation, will be required to achieve realistic seasonal simulations of the Bering Sea ice–ocean system.

scholarly journals ВИХРЕВАЯ СТРУКТУРА ВОСТОЧНО-КАМЧАТСКОГО ТЕЧЕНИЯ ПО СПУТНИКОВЫМ НАБЛЮДЕНИЯМ

2019 ◽  
Author(s):  
N.M. Vakulskaya ◽  
V.A. Dubina ◽  
V.V. Plotnikov
Keyword(s):  
Bering Sea ◽  
Life Time ◽  
Ice Cover ◽  
Winter Monsoon ◽  
The North ◽  
Ice Drift ◽  
Kamchatka Current ◽  
North And South ◽  
Multisensor Data ◽  
The Bering Sea

На основе анализа архива спутниковых мультисенсорных данных исследована динамика ледяного покрова в области ВосточноКамчатского течения. При развитом зимнем муссоне плавучий лёд смещается вдоль побережья Камчатки на юг, трассируя разномасштабные вихри, которые возникают при взаимодействии потока ВосточноКамчатского течения с неоднородностями береговой черты и континентального склона. Средняя скорость дрейфа, рассчитанная по изображениям, полученным в марте 2016 г. в один день с разницей в 110 мин, составила 0,25 м/с, что в два с половиной раза превысило суточное значение. На севере и на юге района значения скорости дрейфа превышали скорости в центральной части. При ослаблении зимнего муссона в поле дрейфующего льда в западной части Берингова моря образуются хорошо выраженные грибовидные структуры, горизонтальные размеры которых могут превышать 200 км. Наряду с известными ранее синоптическими вихревыми образованиями синоптического масштаба спутниковые данные высокого (10 15 м) и среднего (250 м) пространственного разрешения позволили зарегистрировать многочисленные мезомасштабные циклоны диаметром 10 25 км и временем жизни от 1 до 14 суток. Ключевые слова: Берингово море, ледяной покров, MODIS, Landsat, дрейф льда, грибовидные течения, мезомасштабные вихри.On the basis of the analysis of the satellite multisensor data archive, the dynamics of the ice cover in the region of the East Kamchatka Current is investigated. With the developed winter monsoon, floating ice shifts along the Kamchatka coast to the south, tracing the multiscale eddies that appear when the East Kamchatka stream interacts with the inhomogeneities of the coastline and the continental slope. The average drift speed calculated from images taken in March 2016 on the same day with a difference of 110 min was 0.25 m / s, which was two and a half times higher than the daily value. On the north and south of the region, the drift velocity values exceeded the velocities in the central part. With the attenuation of the winter monsoon in the field of drifting ice in the western part of the Bering Sea, welldefined mushroomlike structures are formed, the horizontal dimensions of which can exceed 200 km. Together previously known synoptic eddy formations of a synoptic scale, satellite data of high (10 15 m) and moderate (250 m) spatial resolution made it possible to register numerous mesoscale cyclones with a diameter of 10 25 km and a life time of 1 to 14 days. Keywords: Bering Sea, sea ice cover, MODIS, Landsat, ice drift, mushroom currents, submesoscale eddies.На основе анализа архива спутниковых мультисенсорных данных исследована динамика ледяного покрова в области ВосточноКамчатского течения. При развитом зимнем муссоне плавучий лёд смещается вдоль побережья Камчатки на юг, трассируя разномасштабные вихри, которые возникают при взаимодействии потока ВосточноКамчатского течения с неоднородностями береговой черты и континентального склона. Средняя скорость дрейфа, рассчитанная по изображениям, полученным в марте 2016 г. в один день с разницей в 110 мин, составила 0,25 м/с, что в два с половиной раза превысило суточное значение. На севере и на юге района значения скорости дрейфа превышали скорости в центральной части. При ослаблении зимнего муссона в поле дрейфующего льда в западной части Берингова моря образуются хорошо выраженные грибовидные структуры, горизонтальные размеры которых могут превышать 200 км. Наряду с известными ранее синоптическими вихревыми образованиями синоптического масштаба спутниковые данные высокого (10 15 м) и среднего (250 м) пространственного разрешения позволили зарегистрировать многочисленные мезомасштабные циклоны диаметром 10 25 км и временем жизни от 1 до 14 суток. Ключевые слова: Берингово море, ледяной покров, MODIS, Landsat, дрейф льда, грибовидные течения, мезомасштабные вихри.

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