Multiyear variability of atmospheric processes and ice cover in the Laptev Sea since 1942 to 2019

2020 ◽  
Author(s):  
Anna Timofeeva ◽  
Vladimir Ivanov ◽  
Alexander Yulin ◽  
Stepan Khotchenkov
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Ice Cover ◽  
Laptev Sea ◽  
Positive Temperature ◽  
Sea Ice Extent ◽  
Air Masses ◽  
Ice Conditions ◽  
The Laptev Sea ◽  
Melting Season

<p>The Laptev Sea is influenced by synoptic regions of the Atlantic-Eurasian sector of the Northern Hemisphere. Types of large-scale processes are consider according to the G. J. Vangengeim typization: West (W) circulation form, with dominating zonal transport of air masses, East (E) and meridional (C) circulation forms with opposite phases of geographic orientation in the troposphere of the anticyclones ridges axes, blocking the Western transfer of air masses and developing the meridional circulation at high and middle latitudes. The Laptev Sea ice extent at the end of the melting season has a strong interannual variability, the oscillations amplitude reaches 86%.</p><p>The paper considers analysis of long-term trends of the large-scale atmosphere processes realignment and multiyear variability of the air temperature and ice cover anomalies in the Laptev Sea. According to multiyear course of integral anomalies values four steady periods of homogeneous  tendency of climatic processes revealed and described for data series from 1942 to 2019 (air reconnaissance and satellite data).</p><p>The types of ice conditions development (severe, medium, mild) at the end of the melting season were determined for the entire series of observations. More than half of cases during 78 years are distinguished as medium type of ice conditions. The repeatability of severe and mild types is almost the same numerically but varies in time according to revealed periods.</p><p>During 1942-1947 years in the Laptev Sea the “warming” period occurred (same for the whole polar region), known as the warming of the Arctic of 30th. At this period positive temperature anomalies and negative anomalies of sea ice extent (mean -2%) were dominated. During subsequent period 1948-1989 years the positive temperature trend has changed to the steady negative. The most dramatic temperature drops were observed in the 60-70<sup>th</sup>. Positive ice anomalies increased (mean 9%), in August Laptev Sea remained mostly covered by ice. Of the 42 years 28 refer to the medium type of ice conditions, 11 to the severe. During the period 1990-2004 years frequent interannual rearrangements of the atmosphere circulation and multidirectional fluctuations of temperature and ice cover anomalies were observed. On average, the temperature and ice cover during the period are close to the long-term norm. After 2005 temperature regime in the polar climate system has changed. This period is the warmest for the whole observations series in the Laptev Sea. Ice extent at the end of the melting season steady decreases and shows dramatic growth of negative anomalies values and occur of extremely low anomaly for the entire observation period (up to -54-55%). The average negative ice anomaly for the period is -26.4 %. Of the 15 years 9 refer to the mild type of ice conditions.</p>

scholarly journals Variability and trends in Laptev Sea ice outflow between 1992–2011

2013 ◽  
Vol 7 (1) ◽  
pp. 349-363 ◽  
Author(s):  
T. Krumpen ◽  
M. Janout ◽  
K. I. Hodges ◽  
R. Gerdes ◽  
F. Girard-Ardhuin ◽  
...  
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Ice Cover ◽  
Late Winter ◽  
Laptev Sea ◽  
Concentration Data ◽  
Sea Ice Extent ◽  
Ice Drift ◽  
Wind Velocities ◽  
The Laptev Sea

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average total winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 105 km2. The average transport across the NB (2.87 × 105 km2) is thereby higher than across the EB (0.61 × 105 km2), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 105 km2 decade−1, p > 0.95), dominated by increasing export through the EB (0.55 × 105 km2 decade−1, p > 0.90), while the increase in export across the NB is smaller (0.3 × 105 km2 decade−1) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. The increased transport rates are rather the consequence of a changing ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the central and southeastern Laptev Sea. Furthermore, our results imply that years of high ice export in late winter (February to May) have a thinning effect on the ice cover, which in turn preconditions the occurence of negative sea ice extent anomalies in summer.

scholarly journals Variability and trends in Laptev Sea ice outflow between 1992–2011

2012 ◽  
Vol 6 (4) ◽  
pp. 2891-2930 ◽  
Author(s):  
T. Krumpen ◽  
M. Janout ◽  
K. I. Hodges ◽  
R. Gerdes ◽  
F. Girard-Ardhuin ◽  
...  
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Back Propagation ◽  
Late Winter ◽  
Laptev Sea ◽  
Concentration Data ◽  
Sea Ice Extent ◽  
Ice Drift ◽  
Wind Velocities ◽  
The Laptev Sea

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 105 km2. The average transport across the NB (2.87 × 105 km2) is thereby higher than across the EB (0.61 × 105 km2), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 105 km2/decade, p > 0.95), dominated by increasing export through the EB (0.55 × 105 km2/decade, p > 0.90), while the increase in export across the NB is small (0.3 × 105 km2/decade) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. Following Spreenet al. (2011), we therefore assume that changes in ice flux rates may be related to changes in the ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the Central and South-Eastern Laptev Sea. Furthermore, our results imply that the late winter (February to May) ice area flux may at least partially control the summer sea ice extent in the Laptev Sea.

scholarly journals Analyzing links between simulated Laptev Sea sea ice and atmospheric conditions over adjoining landmasses using causal-effect networks

2020 ◽  
Vol 14 (11) ◽  
pp. 4201-4215
Author(s):  
Zoé Rehder ◽  
Anne Laura Niederdrenk ◽  
Lars Kaleschke ◽  
Lars Kutzbach
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Causal Effect ◽  
Ice Cover ◽  
Meridional Wind ◽  
Specific Humidity ◽  
Laptev Sea ◽  
Atmospheric Conditions ◽  
Thermodynamic Variables ◽  
The Laptev Sea

Abstract. We investigate how sea ice interacts with the atmosphere over adjacent landmasses in the Laptev Sea region as a step towards a better understanding of the connection between sea ice and permafrost. We identify physical mechanisms as well as local and large-scale drivers of sea-ice cover with a focus on one region with highly variable sea-ice cover and high sea-ice productivity: the Laptev Sea region. We analyze the output of a coupled ocean–sea-ice–atmosphere–hydrological-discharge model with two statistical methods. With the recently developed causal-effect networks we identify temporal links between different variables, while we use composites of high- and low-sea-ice-cover years to reveal spatial patterns and mean changes in variables. We find that in the model local sea-ice cover is a driven rather than a driving variable. Springtime melt of sea ice in the Laptev Sea is mainly controlled by atmospheric large-scale circulation, mediated through meridional wind speed and ice export. During refreeze in fall thermodynamic variables and feedback mechanisms are important – sea-ice cover is interconnected with air temperature, thermal radiation and specific humidity. Though low sea-ice cover leads to an enhanced southward transport of heat and moisture throughout summer, links from sea-ice cover to the atmosphere over land are weak, and both sea ice in the Laptev Sea and the atmospheric conditions over the adjacent landmasses are mainly controlled by common external drivers.

scholarly journals Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover

2017 ◽  
Author(s):  
Polona Itkin ◽  
Thomas Krumpen
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Sensitivity Study ◽  
Late Winter ◽  
Laptev Sea ◽  
Sea Ice Extent ◽  
Ice Dynamics ◽  
Sea Ice Thickness ◽  
Statistical Connection ◽  
The Laptev Sea

Abstract. Recent studies based on satellite observations have shown that there is a high statistical connection between the late winter (Feb-May) sea ice export out the Laptev Sea, and the ice coverage in the following summer. By means of airborne sea ice thickness surveys made over pack ice areas in the southeastern Laptev Sea, we show that years of offshore directed sea ice transport have a thinning effect on the late winter sea ice cover, and vice versa. Once temperature rise above freezing, these thin ice zones melt more rapidly and hence, precondition local anomalies in summer sea ice cover. The preconditioning effect of the winter ice dynamics for the summer sea ice extent is confirmed with a model sensitivity study where we replace the inter-annual summer atmospheric forcing by a climatology. In the model, years with high late winter sea ice export always result in a reduced sea ice cover, and vice versa. We conclude that the observed tendency towards an increased ice export further accelerates ice retreat in summer. The mechanism presented in this study highlights the importance of winter ice dynamics for summer sea ice anomalies in addition to atmospheric processes acting on the ice cover between May and September. Finally, we show that ice dynamics in winter not only precondition local summer ice extent, but also accelerate fast ice decay.

scholarly journals Analyzing links between simulated Laptev Sea sea ice and atmospheric conditions over adjoining landmasses using causal-effect networks

2020 ◽  
Author(s):  
Zoé Rehder ◽  
Anne Laura Niederdrenk ◽  
Lars Kaleschke ◽  
Lars Kutzbach
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Causal Effect ◽  
Ice Cover ◽  
Specific Humidity ◽  
The Arctic ◽  
Laptev Sea ◽  
Atmospheric Conditions ◽  
Physical Mechanisms ◽  
The Laptev Sea

Abstract. The connection between permafrost and sea ice in the Arctic is not fully understood. As a first step, we investigate how sea ice interacts with the atmosphere over the permafrost landscape. Prior research established that Arctic-wide sea-ice loss can lead to a warming over circumpolar landmasses. However, it is still unclear which physical mechanisms drive this connection. We address this by identifying these physical mechanisms as well as local and large-scale drivers of sea-ice cover with a focus on one region with highly variable sea-ice cover and high sea-ice productivity: the Laptev Sea region. We analyze the output of coupled a ocean-sea ice-atmosphere-hydrological discharge model with two statistical methods. With the recently developed Causal Effect Networks we identify temporal links between different variables, while we use composites of high- and low-sea-ice-cover years to reveal spatial patterns and mean changes in variables. We find that in the model local sea-ice cover is a driven rather than a driving variable. Springtime melt of sea ice in the Laptev Sea is mainly controlled by atmospheric large-scale circulation, mediated through meridional wind speed and ice export. During refreeze in fall thermodynamic variables and feedback mechanisms are important - sea-ice cover is interconnected with air temperature, thermal radiation and specific humidity. Though low sea-ice cover leads to an enhanced southward transport of heat and moisture throughout summer, links from sea-ice cover to the atmosphere over land are weak, and both sea ice in the Laptev Sea and the atmospheric conditions over the adjacent landmasses are mainly controlled by common external drivers.

scholarly journals Near-bottom water warming in the Laptev Sea in response to atmospheric and sea-ice conditions in 2007

2011 ◽  
Vol 30 (1) ◽  
pp. 6425 ◽  
Author(s):  
Jens A. Hölemann ◽  
Sergey Kirillov ◽  
Torben Klagge ◽  
Andrey Novikhin ◽  
Heidemarie Kassens ◽  
...  
Keyword(s):  
Sea Ice ◽  
Bottom Water ◽  
Laptev Sea ◽  
Ice Conditions ◽  
The Laptev Sea

scholarly journals Stages of sea ice development in the Laptev sea

2017 ◽  
pp. 5-15 ◽  
Author(s):  
S. V. Hotchenkov
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Ice Thickness ◽  
Winter Period ◽  
First Year ◽  
Laptev Sea ◽  
Partial Concentration ◽  
Fast Ice ◽  
Drifting Ice ◽  
The Laptev Sea

Variability of the stages of sea ice development in the Laptev Sea is assessed with 10-days periodicity for the autumn — winter period on a basis of AARI digital ice charts for 1997–2017. Difference in formation of the stages of ice development (ice thickness) was revealed between the drifting and fast ice, which is manifested in an earlier appearance of the first-year ice for the fast ice area and in its partial concentration. On average, the ice cover of the Laptev Sea is by 60 % composed of thick first-year ice, most of which is formed within the fast ice area — 38%, while the area of drifting ice is 1,5 times larger.

scholarly journals Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay

2017 ◽  
Vol 11 (5) ◽  
pp. 2383-2391 ◽  
Author(s):  
Polona Itkin ◽  
Thomas Krumpen
Keyword(s):  
Sea Ice ◽  
Numerical Models ◽  
Ice Cover ◽  
Sensitivity Study ◽  
Arctic Sea Ice ◽  
Late Winter ◽  
Laptev Sea ◽  
Ice Dynamics ◽  
Fast Ice ◽  
The Laptev Sea

Abstract. Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

Comparison of emperor penguin declines between Pointe Géologie and Haswell Island over the past 50 years

2011 ◽  
Vol 23 (5) ◽  
pp. 461-468 ◽  
Author(s):  
Christophe Barbraud ◽  
Maria Gavrilo ◽  
Yuri Mizin ◽  
Henri Weimerskirch
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Future Climate Change ◽  
Emperor Penguin ◽  
Sea Ice Extent ◽  
Island Populations ◽  
Dramatic Decline ◽  
Ice Conditions ◽  
Long Term Trends

AbstractThe emperor penguin (Aptenodytes forsteri) is highly dependent on sea ice conditions, and future climate change may affect its distribution and numbers. Most studies on the demography and population dynamics of emperor penguins in relation to sea ice characteristics were conducted at a single colony (Pointe Géologie). Several non-exclusive hypotheses have been proposed to explain the dramatic decline of this colony, including changes in sea ice conditions, predation, flipper banding and human disturbance. Here, we report and analyse updated long-term trends in numbers of breeding pairs made at two colonies (Pointe Géologie and Haswell Island) where counts are comparable. Similar changes were observed for both colonies and paralleled changes in sea ice extent. At Pointe Géologie and Haswell Island, populations declined similarly and later growth rates were also similar since the early 1990s for Haswell and early 1980s for Pointe Géologie. The magnitude of the decline was similar between both colonies when numbers of breeding pairs were assessed. This study suggests that a common large-scale environmental factor has probably negatively affected both colonies.

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