scholarly journals Classification of surface atmospheric pressure fields in the Laptev and East Siberian seas

2021 ◽  
Vol 67 (4) ◽  
pp. 394-405
Author(s):  
V. S. Porubaev ◽  
L. N. Dyment
Keyword(s):  
Surface Pressure ◽  
Atmospheric Pressure ◽  
Ice Cover ◽  
The Arctic ◽  
Wind Fields ◽  
Arctic Seas ◽  
Pressure Fields ◽  
Ice Drift ◽  
Waves And Currents

The need for classifying surface atmospheric pressure fields over the Arctic seas arose as a method was being developed for predicting the characteristics of discontinuities (leads) in the sea ice cover. Wind, which is determined by the atmospheric pressure field, acts on the ice cover and causes it to drift. Leads are formed in the ice cover due to the irregularity of ice drift. Ice drift can be caused by several factors, such as skewed sea level, tidal waves and currents. However, the main cause of ice drift in the Arctic seas is wind. Each typical field of surface atmospheric pressure corresponds to a certain field of leads in the ice cover. This makes it possible to predict the characteristics of leads in the ice cover by selecting fields similar to predictive fields of atmospheric pressure based on archived data.The variety of atmospheric pressure fields makes it difficult to find an analogue to a given field by simply going through all the corresponding data available in the electronic archive. Classification of atmospheric pressure fields makes it possible to simplify the process of selecting an analogue.To develop the classification, we used daily surface pressure maps at 00 hours GMT for the cold seasons (from mid- October to the end of May) 2016–2021. The atmospheric pressure fields, which were similar in configuration, and hence the wind fields, belonged to the same type. In total, 27 types were identified, applicable both to the Laptev Sea and the East Siberian Sea. Within one type, a division into subtypes was made, depending on the speed of the geostrophic wind.The wind intensity was estimated by the number of isobars multiples of 5 mb on the surface atmospheric pressure map. All the surface pressure fields observed over the waters of the Laptev and East Siberian Seas over the past 5 years have been assigned to one of the types identified using cluster analysis. Each type of atmospheric pressure within the framework of the forecasting method being developed is supposed to correspond to a field of discontinuities in the ice cover.

Bayesian classification of the ice cover of the Arctic seas

2015 ◽  
Vol 51 (9) ◽  
pp. 883-888
Author(s):  
N. Yu. Zakhvatkina ◽  
I. A. Bychkova
Keyword(s):  
Ice Cover ◽  
Bayesian Classification ◽  
The Arctic ◽  
Arctic Seas

scholarly journals Sea ice drift in the Southern Ocean: Regional patterns, variability, and trends

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Ron Kwok ◽  
Shirley S. Pang ◽  
Sahra Kacimi
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Sea Level ◽  
Ice Cover ◽  
The Arctic ◽  
Positive Trend ◽  
Amundsen Sea ◽  
Regional Patterns ◽  
Ice Drift ◽  
Sea Ice Drift

Understanding long-term changes in large-scale sea ice drift in the Southern Ocean is of considerable interest given its contribution to ice extent, to ice production in open waters, with associated dense water formation and heat flux to the atmosphere, and thus to the climate system. In this paper, we examine the trends and variability of this ice drift in a 34-year record (1982–2015) derived from satellite observations. Uncertainties in drift (~3 to 4 km day–1) were assessed with higher resolution observations. In a linear model, drift speeds were ~1.4% of the geostrophic wind from reanalyzed sea-level pressure, nearly 50% higher than that of the Arctic. This result suggests an ice cover in the Southern Ocean that is thinner, weaker, and less compact. Geostrophic winds explained all but ~40% of the variance in ice drift. Three spatially distinct drift patterns were shown to be controlled by the location and depth of atmospheric lows centered over the Amundsen, Riiser-Larsen, and Davis seas. Positively correlated changes in sea-level pressures at the three centers (up to 0.64) suggest correlated changes in the wind-driven drift patterns. Seasonal trends in ice edge are linked to trends in meridional winds and also to on-ice/off-ice trends in zonal winds, due to zonal asymmetry of the Antarctic ice cover. Sea ice area export at flux gates that parallel the 1000-m isobath were extended to cover the 34-year record. Interannual variability in ice export in the Ross and Weddell seas linked to the depth and location of the Amundsen Sea and Riiser-Larsen Sea lows to their east. Compared to shorter records, where there was a significant positive trend in Ross Sea ice area flux, the longer 34-year trends of outflow from both seas are now statistically insignificant.

Regularities and features of ice conditions of the Barents Sea in the second half of XX – early XXI century

2021 ◽  
pp. 179-194
Author(s):  
I.O. Dumanskaya ◽  
Keyword(s):  
Barents Sea ◽  
Ice Cover ◽  
Heat Fluxes ◽  
The Arctic ◽  
Cycle Period ◽  
Arctic Seas ◽  
Sea Ice Extent ◽  
The Barents Sea ◽  
Western Border ◽  
Quantitative Changes

The warming of the Arctic, especially intensified at the beginning of the XXI century, is accompanied by a significant decrease in the area of ice cover in the Arctic seas. The article shows the quantitative changes in the ice parameters of the Barents Sea, as well as factors affecting the formation of ice cover in recent years. In the twenty-first century the frequency of occurrence of mild winters has increased by 17%, the frequency of severe winters has decreased by 19%. Significantly increased the temperature at the meteorological station Malye Karmakuly, water temperature at transect "Kola Meridian", atmospheric and oceanic heat fluxes, and speed of sea currents on the Western border of the Barents sea. The duration of the ice period decreased by an average of 2–3 weeks, and the rate of reduction of ice cover was 7.2% for 10 years. This is the highest speed compared to other Arctic seas. The article shows that the variability of the ice cover of the Barents Sea and other parameters of the natural environment in the region has the cyclic character. Presumably, the cycle period is close to 84 years, which corresponds to the orbital period of Uranium. The minimum sea ice extent after 1935–1945 is expected in the period 2019–2029.

scholarly journals Sea-ice and North Atlantic climate response to CO2-induced warming and cooling conditions

2006 ◽  
Vol 52 (178) ◽  
pp. 433-439 ◽  
Author(s):  
Larissa Nazarenko ◽  
Nickolai Tausnev ◽  
James Hansen
Keyword(s):  
Sea Ice ◽  
Northern Hemisphere ◽  
Surface Pressure ◽  
Climate Model ◽  
Global Climate Model ◽  
Ice Cover ◽  
The Arctic ◽  
Normal Surface ◽  
Sea Ice Extent ◽  
Polar Cell

AbstractUsing a global climate model coupled with an ocean and a sea-ice model, we compare the effects of doubling CO2 and halving CO2 on sea-ice cover and connections with the atmosphere and ocean. An overall warming in the 2 × CO2 experiment causes reduction of sea-ice extent by 15%, with maximum decrease in summer and autumn, consistent with observed seasonal sea-ice changes. The intensification of the Northern Hemisphere circulation is reflected in the positive phase of the Arctic Oscillation (AO), associated with higher-than-normal surface pressure south of about 50° N and lower-than-normal surface pressure over the high northern latitudes. Strengthening the polar cell causes enhancement of westerlies around the Arctic perimeter during winter. Cooling, in the 0.5 × CO2 experiment, leads to thicker and more extensive sea ice. In the Southern Hemisphere, the increase in ice-covered area (28%) dominates the ice-thickness increase (5%) due to open ocean to the north. In the Northern Hemisphere, sea-ice cover increases by only 8% due to the enclosed land/sea configuration, but sea ice becomes much thicker (108%). Substantial weakening of the polar cell due to increase in sea-level pressure over polar latitudes leads to a negative trend of the winter AO index. The model reproduces large year-to-year variability under both cooling and warming conditions.

scholarly journals Wintertime Methane Emission From the Barents and Kara Seas and Sea of Okhotsk: Satellite Evidence.

2021 ◽  
Author(s):  
Leonid Yurganov ◽  
Dustin Carroll ◽  
Andrey Pnyushkov ◽  
Igor Polyakov ◽  
Hong Zhang
Keyword(s):  
Remote Sensing ◽  
Sea Ice ◽  
Water Column ◽  
Mixed Layer Depth ◽  
Deep Ocean ◽  
Ice Cover ◽  
The Arctic ◽  
Atmospheric Methane ◽  
Arctic Seas ◽  
Ir Radiation

<p><span>Existence of strong seabed sources of methane, including gas hydrates, in the Arctic and sub-Arctic seas with proven oil/gas deposits </span><span>i</span><span>s well documented. Enhanced concentrations of dissolved methane in </span><span>deep layers</span><span> are widely observed</span><span>. </span><span>Many of </span><span>marine</span><span> sources are highly sensitive to climate change; however, the Arctic methane sea-to-air flux remains poorly understood</span><span>:</span><span> </span><span>harsh</span><span> natural conditions prevent in-situ measurements during winter. Satellite remote sensing, based on terrestrial outgoing Thermal IR radiation</span><span> </span><span>measurements</span><span>, provides a novel alternative to those efforts. We present year-round methane data from 3 orbital sounders since 2002. Those data confirm that negligible amounts of methane are fluxed from the seabed to the atmosphere during summer. In summer, the water column is strongly stratified from sea-ice melt </span><span>and solar warming. As a result, </span><span> ~90% of </span><span>dissolved </span><span>methane is oxidized by bacteria. Conversely, </span><span>some </span><span>marine areas are characterized by positive atmospheric methane anomalies that begin in November. During winter, ocean stratification weakens</span><span>,</span><span> </span><span>convection and </span><span>winter storms </span><span>mix the water column efficiently</span><span>. We also find that the amplitudes of the seasonal cycles over Kara and Okhotsk Seas have increased during last 18 years</span><span> </span><span>due to winter concentration growth. There may be several factors </span><span>responsible for sea-air flux</span><span>: </span><span>growing emission from clathrates due to warming</span><span>, changes in methane transport from the seabed to the surface, changes in microbial </span><span>oxidation</span><span>, </span><span>ice cover, </span><span>etc</span><span>. Finally, </span><span>methane</span><span> remote sensing results are compared to available observations of temperature in deep ocean layers, estimates of Mixed Layer Depth, and satellite microwave sea-ice cover measurements.</span></p><p> </p>

Landfast ice zoning from SAR imagery

2020 ◽  
Author(s):  
Valeria Selyuzhenok ◽  
Denis Demchev ◽  
Thomas Krumpen
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Drift ◽  
Landfast Ice ◽  
Sea Ice Drift ◽  
Ice Conditions ◽  
Sar Imagery

<p>Landfast sea ice is a dominant sea ice feature of the Arctic coastal region. As a part of Arctic sea ice cover, landfast ice is an important part of coastal ecosystem, it provides functions as a climate regulator and platform for human activity. Recent changes in sea ice conditions in the Arctic have also affected landfast ice regime. At the same time, industrial interest in the Arctic shelf seas continue to increase. Knowledge on local landfast ice conditions are required to ensure safety of on ice operations and accurate forecasting.  In order to obtain a comprehensive information on landfast ice state we use a time series of wide swath SAR imagery.  An automatic sea ice tracking algorithm was applied to the sequential SAR images during the development stage of landfast ice cover. The analysis of resultant time series of sea ice drift allows to classify homogeneous sea ice drift fields and timing of their attachment to the landfast ice. In addition, the drift data allows to locate areas of formation of grounded sea ice accumulation called stamukha. This information сan be useful for local landfast ice stability assessment. The study is supported by the Russian Foundation for Basic Research (RFBR) grant 19-35-60033.</p>

scholarly journals Trends in the intensity of dense water cascading from the Arctic shelves due to ice cover reduction in the Arctic seas

2021 ◽  
Vol 67 (4) ◽  
pp. 318-327
Author(s):  
F. K. Tuzov
Keyword(s):  
Arctic Ocean ◽  
Barents Sea ◽  
Beaufort Sea ◽  
Ice Cover ◽  
The Arctic ◽  
Arctic Seas ◽  
Dense Water ◽  
The Barents Sea ◽  
The Arctic Ocean ◽  
Shelf Seas

The article discusses the possible relationship between changes in the ice cover area of the shelf seas of the Arctic Ocean and the intensity of dense water cascading, based on calculation data obtained with the NEMO model for the period 1986–2010, with the findings issued at 5-day intervals and a spatial resolution of 1/10°. The cascading cases were calculated using an innovative method developed by the author. The work is based on the assumption that as the ice cover in the seas retreats, the formation of cooled dense water masses is intensified, which submerge and flow down the slope from the shelf to great depths. Thus, in the Arctic shelf seas, the mechanism of water densification due to cooling is added to the mechanism of water densification during ice formation, or, replaces it for certain regions. It was found that in the Barents Sea, the Laptev Sea and the Beaufort Sea, a decrease in the ice cover area causes an increase in the number of cases of cascading. However, in most of the Arctic seas, as the area of ice cover decreases, the number of cases of cascading also decreases. As a consequence, for the whole Arctic shelf area, the number of cases of cascading also decreases with decreasing ice cover. It is shown that in the Beaufort Sea the maximum number of cascading cases was observed in the winter period of 2007–2008, which was preceded by the summer minimum of the ice cover area in the Arctic Ocean. In the Barents Sea after 2000, a situation has been observed where the ice area has been decreasing to zero values, whereas the number of cascading cases has for some time (1 month approximately) remained close to high winter values. This possibly means that the cooling and densification of the waters in ice-free areas occurs due to thermal convection. Based on the calculation of the number of cases of cascading, it can be argued that the intensification of cascading due to a reduction in the ice cover is a feature of individual seas of the Arctic Ocean, those in which there is no excessive freshening of the upper water layer due to ice melting.

Methods of parameters estimate of ice formations

2019 ◽  
Vol 65 (1) ◽  
pp. 77-91
Author(s):  
A. K. Naumov ◽  
E. A. Skutina
Keyword(s):  
Dynamic Characteristics ◽  
Ice Cover ◽  
Aerial Survey ◽  
Water Area ◽  
Morphometric Parameters ◽  
The Arctic ◽  
Arctic Seas ◽  
Protection Measures ◽  
Ice Floes ◽  
Ice Radar

The ice cover of the Arctic Seas is an important component of the natural conditions. It is impossible the construction and safe exploitation of the hydrotechnical structures and lines of communications on the shelf, reasonable planning and conducting of cargo and transport operations, organization of environmental protection measures without taking into account an ice cover.The information on morphometric and dynamic characteristics of ice formations, physical and mechanical ice properties, presence of icebergs and its bergy bits with various mortphometric and dynamic characteristics in the water area are necessary for an organization of successful activity on the shelf (design of hydrotechnical structures, planning of the work etc).The present article is concerned with the issues of estimation of ice formations morphometric parameters. The different remote observations methods on ice floes and icebergs are considered in the article: aerial survey, radar survey, observations using ice radar and geodetic instruments, visual observations, sonar survey of ice cover.The goal of the work is the description of peculiarities of various remote methods of observations. For each of the considered methods, the conditions of its application and peculiarities of data obtainment are considered; the list of morphometric parameters, that can be estimated, using results of corresponding observations is indicated.The mentioned algorithms and formulas are actively used during ice surveying works at the present time. The knowledge of various methods peculiarities allows to plan the composition of research works depending on their goals and tasks, determine the terms of their performance.The main merits and demerits of the considered methods of data obtainment and estimations of ice formations morphometrical parameters are phrased in the conclusion.

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