scholarly journals Contributions of advection and melting processes to the decline in sea ice in the Pacific sector of the Arctic Ocean

2019 ◽  
Vol 13 (5) ◽  
pp. 1423-1439 ◽  
Author(s):  
Haibo Bi ◽  
Qinghua Yang ◽  
Xi Liang ◽  
Liang Zhang ◽  
Yunhe Wang ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Melting Process ◽  
The Arctic ◽  
Positive Trend ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Ice Retreat ◽  
The Mean ◽  
Sea Ice Retreat

Abstract. The Pacific sector of the Arctic Ocean (PA, hereafter) is a region sensitive to climate change. Given the alarming changes in sea ice cover during recent years, knowledge of sea ice loss with respect to ice advection and melting processes has become critical. With satellite-derived products from the National Snow and Ice Center (NSIDC), a 38-year record (1979–2016) of the loss in sea ice area in summer within the Pacific-Arctic (PA) sector due to the two processes is obtained. The average sea ice outflow from the PA to the Atlantic-Arctic (AA) Ocean during the summer season (June–September) reaches 0.173×106 km2, which corresponds to approximately 34 % of the mean annual export (October to September). Over the investigated period, a positive trend of 0.004×106 km2 yr−1 is also observed for the outflow field in summer. The mean estimate of sea ice retreat within the PA associated with summer melting is 1.66×106 km2, with a positive trend of 0.053×106 km2 yr−1. As a result, the increasing trends of ice retreat caused by outflow and melting together contribute to a stronger decrease in sea ice coverage within the PA (0.057×106 km2 yr−1) in summer. In percentage terms, the melting process accounts for 90.4 % of the sea ice retreat in the PA in summer, whereas the remaining 9.6 % is explained by the outflow process, on average. Moreover, our analysis suggests that the connections are relatively strong (R=0.63), moderate (R=-0.46), and weak (R=-0.24) between retreat of sea ice and the winds associated with the dipole anomaly (DA), North Atlantic Oscillation (NAO), and Arctic Oscillation (AO), respectively. The DA participates by impacting both the advection (R=0.74) and melting (R=0.55) processes, whereas the NAO affects the melting process (R=-0.46).

scholarly journals Contributions of advection and melting processes to the decline in sea ice in the Pacific sector of the Arctic Ocean

2019 ◽  
Author(s):  
Haibo Bi ◽  
Qinghua Yang ◽  
Xi Liang ◽  
Haijun Huang
Keyword(s):  
Sea Ice ◽  
Melting Process ◽  
The Arctic ◽  
Positive Trend ◽  
Ice Coverage ◽  
The Pacific ◽  
Ice Retreat ◽  
The Mean ◽  
Sea Ice Retreat ◽  
Increasing Trends

Abstract. The Pacific–Arctic (PA) Ocean is a region sensitive to climate change. Given the alarming changes in sea ice cover during recent years, knowledge of sea ice loss with respect to ice advection and melting processes has become critical. With satellite-derived products from the National Snow and Ice Center (NSIDC), a 38-yr record (1979–2016) of the loss in sea ice area in summer within the Pacific-Arctic (PA) sector due to the two processes is obtained. The average sea ice outflow from the PA to the Atlantic-Arctic (AA) Ocean during the summer season (June–September) reaches 173 × 103 km2, which corresponds to approximately 34 % of the mean annual export (October to September). Over the investigated period, a positive trend of 4.2 × 103 km2/yr is also observed for the outflow field in summer. The mean estimate of sea ice retreat within the PA associated with summer melting is 1.66 × 106 km2, with a positive trend of 53.1 × 103 km2/yr. As a result, the increasing trends of ice retreat caused by outflow and melting together contribute to a stronger decrease in sea ice coverage within the PA (57.3 × 103 km2/yr) in summer. In percentage terms, the melting process accounts for 90.4 % of the sea ice retreat in the PA in summer, whereas the remaining 9.6 % is explained by the outflow process, on average. Moreover, our analysis suggests that the connections are relatively strong (R = 0.63), moderate (R = −0.46), and weak (R = −0.24) between retreat of sea ice and the winds associated with the Dipole Anomaly (DA), North Atlantic Oscillation (NAO), and Arctic Oscillation (AO), respectively. The DA participates by impacting both the advection (R = 0.74) and melting (R = 0.55) processes, whereas the NAO affects the melting process (R = −0.46).

scholarly journals Attribution of the Recent Winter Sea Ice Decline over the Atlantic Sector of the Arctic Ocean*

2015 ◽  
Vol 28 (10) ◽  
pp. 4027-4033 ◽  
Author(s):  
Doo-Sun R. Park ◽  
Sukyoung Lee ◽  
Steven B. Feldstein
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Environmental Changes ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Positive Trend ◽  
Ir Radiation ◽  
Atlantic Sector ◽  
Sea Ice Decline ◽  
The Arctic Ocean

Abstract Wintertime Arctic sea ice extent has been declining since the late twentieth century, particularly over the Atlantic sector that encompasses the Barents–Kara Seas and Baffin Bay. This sea ice decline is attributable to various Arctic environmental changes, such as enhanced downward infrared (IR) radiation, preseason sea ice reduction, enhanced inflow of warm Atlantic water into the Arctic Ocean, and sea ice export. However, their relative contributions are uncertain. Utilizing ERA-Interim and satellite-based data, it is shown here that a positive trend of downward IR radiation accounts for nearly half of the sea ice concentration (SIC) decline during the 1979–2011 winter over the Atlantic sector. Furthermore, the study shows that the Arctic downward IR radiation increase is driven by horizontal atmospheric water flux and warm air advection into the Arctic, not by evaporation from the Arctic Ocean. These findings suggest that most of the winter SIC trends can be attributed to changes in the large-scale atmospheric circulations.

Atmospheric and oceanic drivers of regional Arctic winter sea-ice variability in present and future climates

2021 ◽  
Author(s):  
Jakob Dörr ◽  
Marius Årthun ◽  
Tor Eldevik ◽  
Erica Madonna
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Heat Transport ◽  
Barents Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ocean Heat Transport ◽  
The Pacific ◽  
Arctic Sea ◽  
The Arctic Ocean

<p>The recent retreat of Arctic sea ice area is overlaid by strong internal variability on all timescales. In winter, sea ice retreat and variability are currently dominated by the Barents Sea, primarily driven by variable ocean heat transport from the Atlantic. Climate models from the latest intercomparison project CMIP6 project that the future loss of winter Arctic sea ice spreads throughout the Arctic Ocean and, hence, that other regions of the Arctic Ocean will see increased sea-ice variability. It is, however, not known how the influence of ocean heat transport will change, and to what extent and in which regions other drivers, such as atmospheric circulation or river runoff into the Arctic Ocean, will become important. Using a combination of observations and simulations from the Community Earth System Model Large Ensemble (CESM-LE), we analyze and contrast the present and future regional drivers of the variability of the winter Arctic sea ice cover. We find that for the recent past, both observations and CESM-LE show that sea ice variability in the Atlantic and Pacific sector of the Arctic Ocean is influenced by ocean heat transport through the Barents Sea and Bering Strait, respectively. The two dominant modes of large-scale atmospheric variability – the Arctic Oscillation and the Pacific North American pattern – are only weakly related to recent regional sea ice variability. However, atmospheric circulation anomalies associated with regional sea ice variability show distinct patterns for the Atlantic and Pacific sectors consistent with heat and humidity transport from lower latitudes. In the future, under a high emission scenario, CESM-LE projects a gradual expansion of the footprint of the Pacific and Atlantic inflows, covering the whole Arctic Ocean by 2050-2079. This study highlights the combined importance of future Atlantification and Pacification of the Arctic Ocean and improves our understanding of internal climate variability which essential in order to predict future sea ice changes under anthropogenic warming.   </p><p> </p>

scholarly journals Trends and spatial variation in rain-on-snow events over the Arctic Ocean during the early melt season

2020 ◽  
Author(s):  
Tingfeng Dou ◽  
Cunde Xiao ◽  
Jiping Liu ◽  
Qiang Wang ◽  
Shifeng Pan ◽  
...  
Keyword(s):  
Sea Ice ◽  
Phase Change ◽  
Arctic Ocean ◽  
The Arctic ◽  
Onset Date ◽  
Marginal Seas ◽  
Ice Melt ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Liquid Precipitation

Abstract. Rain-on-snow (ROS) events can accelerate the surface ablation of sea ice, thus greatly influencing the ice-albedo feedback. However, the variability of ROS events over the Arctic Ocean is poorly understood due to limited historical station data in this region. In this study early melt season ROS events were investigated based on four widely-used reanalysis products (ERA-Interim, JRA-55, MERRA2 and ERA5) in conjunction with available observations at Arctic coastal stations. The performance of the reanalysis products in representing the timing of ROS events and the phase change of precipitation was assessed. Our results show that ERA-Interim better represents the onset date of ROS events in spring and ERA5 better represents the phase change of precipitation associated with ROS events. All reanalyses indicate that ROS event timing has shifted to earlier dates in recent decades (with maximum trends up to −4 to −6 days/decade in some regions in ERA-Interim), and that sea ice melt onset in the Pacific sector and most of the Eurasian marginal seas is correlated with this shift. There has been a clear transition from solid to liquid precipitation, leading to more ROS events in spring, although large discrepancies were found between different reanalysis products. In ERA5, the shift from solid to liquid precipitation phase during the early melt season has directly contributed to a reduction in spring snow depth on sea ice by more than −0.5 cm/decade averaged over the Arctic Ocean since 1980, with the largest contribution (about −2.0 cm/decade) in the Kara-Barents Seas and Canadian Arctic Archipelago.

scholarly journals Seasonal changes in sea ice kinematics and deformation in the Pacific Sector of the Arctic Ocean in 2018/19

2020 ◽  
Author(s):  
Ruibo Lei ◽  
Mario Hoppmann ◽  
Bin Cheng ◽  
Guangyu Zuo ◽  
Dawei Gui ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Temporary Increase ◽  
Momentum Exchange ◽  
Pressure System ◽  
The Pacific ◽  
Ice Drift ◽  
The Arctic Ocean

Abstract. Arctic sea ice kinematics and deformation play significant roles in heat and momentum exchange between atmosphere and ocean. However, mechanisms regulating their changes at seasonal scales remain poorly understood. Using position data of 32 buoys in the Pacific sector of the Arctic Ocean (PAO), we characterized spatiotemporal variations in ice kinematics and deformation for autumn–winter 2018/19. In autumn, sea ice drift response to wind forcing and inertia were stronger in the southern and western than in the northern and eastern parts of the PAO. These spatial heterogeneities decreased gradually from autumn to winter, in line with the seasonal evolution of ice concentration and thickness. Areal localization index decreased by about 50 % from autumn to winter, suggesting the enhanced localization of intense ice deformation as the increased ice mechanical strength. In winter 2018/19, a highly positive Arctic Dipole and a weakened high pressure system over the Beaufort Sea led to a distinct change in ice drift direction and an temporary increase in ice deformation. During the freezing season, ice deformation rate in the northern part of the PAO was about 2.5 times that in the western part due to the higher spatial heterogeneity of oceanic and atmospheric forcing in the north. North–south and east–west gradients in sea ice kinematics and deformation of the PAO observed in autumn 2018 are likely to become more pronounced in the future as sea ice losses at higher rates in the western and southern than in the northern and western parts.

Sea-ice topography of the Arctic Ocean in the region 70° W to 25° E

1981 ◽  
Vol 302 (1464) ◽  
pp. 45-85 ◽  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
The Arctic ◽  
Positive Correlation ◽  
Negative Exponential Distribution ◽  
The Arctic Ocean ◽  
Level Ice ◽  
The Mean ◽  
Negative Exponential

In October 1976 a cooperative experiment was made to survey the sea-ice topography in the European sector of the Arctic Ocean. H. M. submarine Sovereign acquired 4000 km of ice draft data by using an upward-looking sonar, while a Canadian Forces aircraft flew along the submarine’s track and acquired 2200 km of ice elevation data by using a laser profilometer. The two types of profile were processed in corresponding 100 km section lengths, and the following statistical analyses and comparisons were made: (i) Probability density functions o f ice draft and elevation. Each distribution shows a peak for young ice and for undeformed multi-year ice. At large ice thicknesses the distributions take the analytical form of a negative exponential. The mean drafts enable two distinct geographical ice regimes to be identified. There is an ‘offshore zone’ of very heavy pressure ridging extending up to 400 km from the coasts of Ellesmere Island and of north Greenland, with mean ice draft in the range 5.0 to 7.5 m , while out in the central Arctic Ocean the mean ice draft is lower (3.9—5.1 m) and the characteristics of the ice cover remain homogeneous over a length scale of 1000 km. The transition between the two regimes is abrupt, taking place in less than 25 km. Data from the same part of the central Arctic taken in March 1971 showed a mean ice draft 0.3 m lower, while data from the central Beaufort Sea showed a mean draft more than 0.8 m lower. (ii) Level ice distributions. Ice with a local gradient of less than 1 in 40 was defined as level ice, and used as an indicator of the quantity and thickness distribution of undeformed (i.e. thermodynamically grown) ice in the Arctic Ocean. The distribution has a mode at 3.0—3.1 m draft, and level-ice percentages are in the range 30—40 (bottom side) and 70—80 (top side) in the offshore zone, and 45—55 (bottom) and 85-95 (top) in the central Arctic. Thus about half of the Arctic ice cover consists of deformed ice. (iii) Pressure ridge spacings. The spacings of ridge keels fit a negative exponential distribution, characteristic of randomness, except at close spacings where there is a deficit of keels (explained as a geometrical effect) and at very large spacings where there is an excess (due to the contribution of polynyas). The distribution of sail spacings exhibits these two effects, but also differs from a random distribution at moderate sail separations. (iv) Ridge elevations and drafts. Keel drafts fit a law of form P( h ) d oc exp ( — Ah 2 ) d h , except for an excess of keels at drafts beyond 20 m. There is a positive correlation between mean keel draft and keel frequency. There are 3.5—4.5 keels per kilometre with draft exceeding 9 m in the offshore zone and 2—3 in the central Arctic. Sail elevations fit a law of form P( h ) d h x exp ( — A h ) d h , with a positive correlation between mean sail elevation and sail frequency. The sail elevation and ice elevation distributions can be related by assuming that all thick ice is contained in pressure ridges of triangular cross section. (v) Keel—sail comparison. For the 21 corresponding 100 km sections there are positive correlations between mean sail height and mean keel draft, and between keel frequency and sail frequency. From these it is possible to convert a sail distribution (computed from a laser profile) into a keel distribution, enabling sea ice bulk characteristics to be derived from airborne surveys alone. (vi) Leads and polynyas . A lead was defined as a continuous sequence of depth points greater than 5 m long and not exceeding 1 m draft. The number density n ( d ) of leads per kilometre of width d m fits the power law n ( d ) — 15 d -2 . Exceptionally wide leads were concentrated in the offshore zone and in the marginal ice zone close to the open water of the Greenland Sea.

Sign in / Sign up

Export Citation Format

Share Document