scholarly journals Sea ice volume variability and water temperature in the Greenland Sea

2019 ◽  
Author(s):  
Valeria Selyuzhenok ◽  
Igor Bashmachnikov ◽  
Robert Ricker ◽  
Anna Vesman ◽  
Leonid Bobylev
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Fram Strait ◽  
Greenland Sea ◽  
Nordic Seas ◽  
Ice Volume ◽  
Long Term Variations

Abstract. This study explores a link between the long-term variations in the integral sea ice volume (SIV) in the Greenland Sea and oceanic processes. Using Pan-Arctic Ice Ocean Modelling and Assimilation System (PIOMAS, 1979–2016), we show that the negative tendencies in SIV go in parallel with the increasing ice flux through the Fram Strait. The overall SIV loss in the Greenland Sea comprises 113 km3 per decade, while the total SIV import through the Fram strait is increasing by 115 km3 per decade. An analysis of the ocean temperature and the mixed layer depth (MLD) in the marginal sea ice zone (MIZ), based on ARMOR data-set (1993–2016), revealed doubling of the amount of the upper ocean heat content available for the ice melt in the MIZ. This increase over the 24-year period can solely explain the SIV loss in the Greenland Sea, even when accounting for the increasing SIV flux from the Arctic. The increase in the ocean heat content is found to be linked to an increase in the temperature of the Atlantic water in the Nordic seas, following an increase of ocean heat flux form the subtropical North Atlantic. We argue that the predominantly positive North Atlantic Oscillation (NAO) index during the four recent decades, together with the intensification of the deep convection in the Greenland Sea, are responsible for the overall intensification of the circulation in the Nordic seas, which explains the observed long-term variations of the SIV.

scholarly journals Sea ice volume variability and water temperature in the Greenland Sea

2020 ◽  
Vol 14 (2) ◽  
pp. 477-495 ◽  
Author(s):  
Valeria Selyuzhenok ◽  
Igor Bashmachnikov ◽  
Robert Ricker ◽  
Anna Vesman ◽  
Leonid Bobylev
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Heat Content ◽  
The Arctic ◽  
Fram Strait ◽  
Greenland Sea ◽  
Nordic Seas ◽  
Ice Volume ◽  
Long Term Variations

Abstract. This study explores a link between the long-term variations in the integral sea ice volume (SIV) in the Greenland Sea and oceanic processes. Using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, 1979–2016), we show that the increasing sea ice volume flux through Fram Strait goes in parallel with a decrease in SIV in the Greenland Sea. The overall SIV loss in the Greenland Sea is 113 km3 per decade, while the total SIV import through Fram Strait increases by 115 km3 per decade. An analysis of the ocean temperature and the mixed-layer depth (MLD) over the climatic mean area of the winter marginal sea ice zone (MIZ) revealed a doubling of the amount of the upper-ocean heat content available for the sea ice melt from 1993 to 2016. This increase alone can explain the SIV loss in the Greenland Sea over the 24-year study period, even when accounting for the increasing SIV flux from the Arctic. The increase in the oceanic heat content is found to be linked to an increase in temperature of the Atlantic Water along the main currents of the Nordic Seas, following an increase in the oceanic heat flux from the subtropical North Atlantic. We argue that the predominantly positive winter North Atlantic Oscillation (NAO) index during the 4 most recent decades, together with an intensification of the deep convection in the Greenland Sea, is responsible for the intensification of the cyclonic circulation pattern in the Nordic Seas, which results in the observed long-term variations in the SIV.

scholarly journals Satellite-derived sea ice export and its impact on Arctic ice mass balance

2018 ◽  
Vol 12 (9) ◽  
pp. 3017-3032 ◽  
Author(s):  
Robert Ricker ◽  
Fanny Girard-Ardhuin ◽  
Thomas Krumpen ◽  
Camille Lique
Keyword(s):  
Sea Ice ◽  
Mass Balance ◽  
North Atlantic ◽  
Large Scale ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Volume ◽  
Ice Drift ◽  
Ice Mass Balance ◽  
Arctic Ice

Abstract. Sea ice volume export through the Fram Strait represents an important freshwater input to the North Atlantic, which could in turn modulate the intensity of the thermohaline circulation. It also contributes significantly to variations in Arctic ice mass balance. We present the first estimates of winter sea ice volume export through the Fram Strait using CryoSat-2 sea ice thickness retrievals and three different ice drift products for the years 2010 to 2017. The monthly export varies between −21 and −540 km3. We find that ice drift variability is the main driver of annual and interannual ice volume export variability and that the interannual variations in the ice drift are driven by large-scale variability in the atmospheric circulation captured by the Arctic Oscillation and North Atlantic Oscillation indices. On shorter timescale, however, the seasonal cycle is also driven by the mean thickness of exported sea ice, typically peaking in March. Considering Arctic winter multi-year ice volume changes, 54  % of their variability can be explained by the variations in ice volume export through the Fram Strait.

Modifications of Atlantic inflow along the Fram Strait Branch to the Arctic Ocean and its variability north of Svalbard from ship-borne and moored observations in the last two decades.

2021 ◽  
Author(s):  
Agnieszka Beszczynska-Möller ◽  
Waldemar Walczowski ◽  
Agata Grynczel
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Vertical Structure ◽  
Heat Content ◽  
Atlantic Water ◽  
Ocean Heat Content ◽  
The Arctic ◽  
Fram Strait ◽  
Ocean Atmosphere ◽  
The Arctic Ocean

<p>Understanding variable properties and dynamics of the Atlantic water (AW) inflow into the Arctic Ocean, and their impacts on ocean heat content, ocean-atmosphere-sea ice exchanges, changing sea ice cover and propagation of anomalies are key prerequisites to elucidate drivers and mechanisms behind the new, warmer regime of the Arctic Ocean. As the AW progress northwards, its properties are modified by ocean-atmosphere interactions, mixing and lateral exchanges. Warm anomalies reaching the Arctic Ocean can result from smaller heat loss during the AW northward passage through Fram Strait, and/or from an increased oceanic advection. Vertical structure of the Atlantic water layer implies the depth of winter convection and access to oceanic heat carried northward by the inflow.</p><p>During the last two decades warming of the Atlantic inflow has been reported to progress into the Arctic Ocean, however with strong interannual variations and quasi-periodic pulses of water with extraordinary high temperature. Here we present results from 20 years of annual hydrographic surveys, covering the Atlantic water inflow in the eastern Norwegian and Greenland seas, Fram Strait up to the southern Nansen Basin. Interannual changes in the AW properties and transport are analyzed with a focus on the en route modifications of AW inflow in the Fram Strait Branch and changes in the integrated ocean heat content.</p><p>After leaving Fram Strait, the part of AW continues eastward and enters the Arctic Ocean boundary current along different pathways north of Svalbard. The strongest ocean-atmosphere-sea ice interactions and lateral oceanic exchanges in this region lead to substantial local modification of the Atlantic inflow before it continues farther eastward around the rim of the Arctic Ocean. Observations from year-round moorings deployed since 2013 north of Svalbard are used to describe changes in the Atlantic water properties, vertical structure, and dynamics on monthly to seasonal and interannual time scales and their links to the upstream conditions and local and regional atmospheric forcing. Vertical heat fluxes from the Atlantic layer are derived to evaluate the ocean-air and ocean-sea ice exchanges in the only region of the Arctic Ocean where Atlantic-origin water has still contact with sea ice cover.</p>

scholarly journals Satellite-derived sea-ice export and its impact on Arctic ice mass balance

2018 ◽  
Author(s):  
Robert Ricker ◽  
Fanny Girard-Ardhuin ◽  
Thomas Krumpen ◽  
Camille Lique
Keyword(s):  
Sea Ice ◽  
Mass Balance ◽  
North Atlantic ◽  
Large Scale ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Volume ◽  
Ice Drift ◽  
Ice Mass Balance ◽  
Arctic Ice

Abstract. Ice volume export drives variations of Arctic ice mass balance. It also represents a significant fresh water input to the North Atlantic, which could in turn modulate the intensity of the thermohaline circulation. We present the first estimates of winter sea ice volume export through the Fram Strait using CryoSat-2 sea ice thickness retrievals and three different drift products for the years 2010 to 2017. The export rates vary between −21 and −540 km3/month. We find that ice drift variability is the main driver of annual and interannual ice volume export variability, and that the interannual variations of the ice drift are driven by large scale variability of the atmospheric circulation captured by the Arctic Oscillation and North Atlantic Oscillation indices. On shorter timescale, however, the seasonal cycle is also driven by the mean thickness of exported sea ice, typically peaking in March. Considering Arctic winter multiyear ice volume changes, 54 % of the variability can be explained by the variations of ice volume export through the Fram Strait.

Ocean model formulation influences climate sensitivity

2021 ◽  
Author(s):  
Tido Semmler ◽  
Johann Jungclaus ◽  
Christopher Danek ◽  
Helge F Goessling ◽  
Nikolay Koldunov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Sensitivity ◽  
North Atlantic ◽  
Heat Content ◽  
Ocean Model ◽  
Max Planck ◽  
Coupled Models ◽  
Ocean Heat Uptake ◽  
Marine Research ◽  
Transient Climate Response

<p>The climate sensitivity is known to be mainly determined by the atmosphere model but here we discover that the ocean model can change a given transient climate response (TCR) by as much as 20% while the equilibrium climate sensitivity (ECS) change is limited to 10%. In our study, two different coupled CMIP6 models (MPI-ESM and AWI-CM) in two different resolutions each are compared. The coupled models share the same atmosphere-land component ECHAM6.3, which has been developed at the Max-Planck-Institute for Meteorology (MPI-M). However, as part of MPI-ESM and AWI-CM, ECHAM6.3 is coupled to two different ocean models, namely the MPIOM sea ice-ocean model developed at MPI-M and the FESOM sea ice-ocean model developed at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). A reason for the different TCR is different ocean heat uptake through greenhouse gas forcing in AWI simulations compared to MPI-M simulations. Specifically, AWI-CM simulations show stronger surface heating than MPI-ESM simulations while the MPI-M model accumulates more heat in the deeper ocean. The vertically integrated ocean heat content is increasing stronger in MPI-M model configurations compared to AWI model configurations in the high latitudes. Strong vertical mixing in MPI-M model configurations compared to AWI model configurations seems to be key for these differences. The strongest difference in vertical ocean mixing occurs inside the Weddell Gyre, but there are also important differences in another key region, the northern North Atlantic. Over the North Atlantic, these differences materialize in a lack of a warming hole in AWI model configurations and the presence of a warming hole in MPI-M model configurations. All these differences occur largely independent of the considered model resolutions.</p>

scholarly journals North Atlantic deep water formation and AMOC in CMIP5 models

Ocean Science ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. 609-622 ◽  
Author(s):  
Céline Heuzé
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Deep Water ◽  
Deep Convection ◽  
The Arctic ◽  
Subpolar Gyre ◽  
Deep Water Formation ◽  
Nordic Seas ◽  
Water Formation

Abstract. Deep water formation in climate models is indicative of their ability to simulate future ocean circulation, carbon and heat uptake, and sea level rise. Present-day temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5) models are compared with observations to assess the biases, causes and consequences of North Atlantic deep convection in models. The majority of models convect too deep, over too large an area, too often and too far south. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. Half of the models convect in response to local cooling or salinification of the surface waters; only a third have a dynamic relationship between freshwater coming from the Arctic and deep convection. The models with the most intense deep convection have the warmest deep waters, due to a redistribution of heat through the water column. For the majority of models, the variability of the Atlantic Meridional Overturning Circulation (AMOC) is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas up to 2 years before. In turn, models with the strongest AMOC have the largest heat export to the Arctic. Understanding the dynamical drivers of deep convection and AMOC in models is hence key to realistically forecasting Arctic oceanic warming and its consequences for the global ocean circulation, cryosphere and marine life.

scholarly journals The link between the Barents Sea and ENSO events simulated by NEMO model

Ocean Science ◽  
2012 ◽  
Vol 8 (6) ◽  
pp. 971-982 ◽  
Author(s):  
V. N. Stepanov ◽  
H. Zuo ◽  
K. Haines
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Barents Sea ◽  
Southern Oscillation ◽  
Similar Response ◽  
Enso Events ◽  
Ice Volume ◽  
The North ◽  
The Barents Sea ◽  
The North Atlantic

Abstract. An analysis of observational data in the Barents Sea along a meridian at 33°30' E between 70°30' and 72°30' N has reported a negative correlation between El Niño/La Niña Southern Oscillation (ENSO) events and water temperature in the top 200 m: the temperature drops about 0.5 °C during warm ENSO events while during cold ENSO events the top 200 m layer of the Barents Sea is warmer. Results from 1 and 1/4-degree global NEMO models show a similar response for the whole Barents Sea. During the strong warm ENSO event in 1997–1998 an anomalous anticyclonic atmospheric circulation over the Barents Sea enhances heat loses, as well as substantially influencing the Barents Sea inflow from the North Atlantic, via changes in ocean currents. Under normal conditions along the Scandinavian peninsula there is a warm current entering the Barents Sea from the North Atlantic, however after the 1997–1998 event this current is weakened. During 1997–1998 the model annual mean temperature in the Barents Sea is decreased by about 0.8 °C, also resulting in a higher sea ice volume. In contrast during the cold ENSO events in 1999–2000 and 2007–2008, the model shows a lower sea ice volume, and higher annual mean temperatures in the upper layer of the Barents Sea of about 0.7 °C. An analysis of model data shows that the strength of the Atlantic inflow in the Barents Sea is the main cause of heat content variability, and is forced by changing pressure and winds in the North Atlantic. However, surface heat-exchange with the atmosphere provides the means by which the Barents sea heat budget relaxes to normal in the subsequent year after the ENSO events.

scholarly journals Mechanisms underlying recent decadal changes in subpolar North Atlantic Ocean heat content

2017 ◽  
Vol 122 (9) ◽  
pp. 7181-7197 ◽  
Author(s):  
Christopher G. Piecuch ◽  
Rui M. Ponte ◽  
Christopher M. Little ◽  
Martha W. Buckley ◽  
Ichiro Fukumori
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Heat Content ◽  
Ocean Heat Content

How Well Do Climate Models Reproduce North Atlantic Subtropical Mode Water?

2013 ◽  
Vol 43 (10) ◽  
pp. 2230-2244 ◽  
Author(s):  
Shenfu Dong ◽  
Kathryn A. Kelly
Keyword(s):  
Heat Flux ◽  
Data Assimilation ◽  
North Atlantic ◽  
Climate Models ◽  
Formation Rate ◽  
Heat Content ◽  
Ocean Heat Content ◽  
Upper Ocean ◽  
Upper Ocean Heat Content ◽  
Mode Water

Abstract Formation and the subsequent evolution of the subtropical mode water (STMW) involve various dynamic and thermodynamic processes. Proper representation of mode water variability and contributions from various processes in climate models is important in order to predict future climate change under changing forcings. The North Atlantic STMW, often referred to as Eighteen Degree Water (EDW), in three coupled models, both with data assimilation [GFDL coupled data assimilation (GFDL CDA)] and without data assimilation [GFDL Climate Model, version 2.1 (GFDL CM2.1), and NCAR Community Climate System Model, version 3 (CCSM3)], is analyzed to evaluate how well EDW processes are simulated in those models and to examine whether data assimilation alters the model response to forcing. In comparison with estimates from observations, the data-assimilating model gives a better representation of the formation rate, the spatial distribution of EDW, and its thickness, with the largest EDW variability along the Gulf Stream (GS) path. The EDW formation rate in GFDL CM2.1 is very weak because of weak heat loss from the ocean in the model. Unlike the observed dominant southward movement of the EDW, the EDW in GFDL CM2.1 and CCSM3 moves eastward after formation in the excessively wide GS in the models. However, the GFDL CDA does not capture the observed thermal response of the overlying atmosphere to the ocean. Observations show a robust anticorrelation between the upper-ocean heat content and air–sea heat flux, with upper-ocean heat content leading air–sea heat flux by a few months. This anticorrelation is well captured by GFDL CM2.1 and CCSM3 but not by GFDL CDA. Only GFDL CM2.1 captures the observed anticorrelation between the upper-ocean heat content and EDW volume. This suggests that, although data assimilation corrects the readily observed variables, it degrades the model thermodynamic response to forcing.

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