scholarly journals Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

2016 ◽  
Vol 10 (5) ◽  
pp. 2191-2202 ◽  
Author(s):  
Kwang-Yul Kim ◽  
Benjamin D. Hamlington ◽  
Hanna Na ◽  
Jinju Kim
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Turbulent Heat Flux ◽  
Sea Surface ◽  
The Arctic ◽  
Turbulent Heat ◽  
Arctic Amplification ◽  
Atmospheric Column ◽  
The Arctic Ocean

Abstract. Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents–Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents–Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

scholarly journals Mechanism of Seasonal Arctic Sea Ice Evolution and Arctic Amplification

2016 ◽  
Author(s):  
Kwang-Yul Kim ◽  
Benjamin D. Hamlington ◽  
Hanna Na ◽  
Jinju Kim
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Longwave Radiation ◽  
The Arctic ◽  
Turbulent Heat ◽  
Arctic Amplification ◽  
Ice Melting ◽  
Downward Longwave Radiation

Abstract. Sea ice melting is proposed as a primary reason for the Artic amplification, although physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice melting in the Arctic Ocean and the Arctic amplification. While sea ice melting is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains to be thin in winter only in the Barents-Kara Seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice melting warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be ice free. A 1 % reduction in sea ice concentration in winter leads to ~ 0.76 W m−2 increase in upward heat flux, ~ 0.07 K increase in 850 hPa air temperature, ~ 0.97 W m−2 increase in downward longwave radiation, and ~ 0.26 K increase in surface air temperature. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort Seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara Seas and Laptev, East Siberian, Chukchi, and Beaufort Seas.

scholarly journals Sensitivity of Northern Hemisphere climate to ice–ocean interface heat flux parameterizations

2021 ◽  
Vol 14 (8) ◽  
pp. 4891-4908
Author(s):  
Xiaoxu Shi ◽  
Dirk Notz ◽  
Jiping Liu ◽  
Hu Yang ◽  
Gerrit Lohmann
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Sea Ice ◽  
Temperature Difference ◽  
Climate Model ◽  
Turbulent Heat Flux ◽  
The Arctic ◽  
Ice Thickness ◽  
Turbulent Heat ◽  
Sea Ice Thickness

Abstract. We investigate the impact of three different parameterizations of ice–ocean heat exchange on modeled sea ice thickness, sea ice concentration, and water masses. These three parameterizations are (1) an ice bath assumption with the ocean temperature fixed at the freezing temperature; (2) a two-equation turbulent heat flux parameterization with ice–ocean heat exchange depending linearly on the temperature difference between the underlying ocean and the ice–ocean interface, whose temperature is kept at the freezing point of the seawater; and (3) a three-equation turbulent heat flux approach in which the ice–ocean heat flux depends on the temperature difference between the underlying ocean and the ice–ocean interface, whose temperature is calculated based on the local salinity set by the ice ablation rate. Based on model simulations with the stand-alone sea ice model CICE, the ice–ocean model MPIOM, and the climate model COSMOS, we find that compared to the most complex parameterization (3), the approaches (1) and (2) result in thinner Arctic sea ice, cooler water beneath high-concentration ice and warmer water towards the ice edge, and a lower salinity in the Arctic Ocean mixed layer. In particular, parameterization (1) results in the smallest sea ice thickness among the three parameterizations, as in this parameterization all potential heat in the underlying ocean is used for the melting of the sea ice above. For the same reason, the upper ocean layer of the central Arctic is cooler when using parameterization (1) compared to (2) and (3). Finally, in the fully coupled climate model COSMOS, parameterizations (1) and (2) result in a fairly similar oceanic or atmospheric circulation. In contrast, the most realistic parameterization (3) leads to an enhanced Atlantic meridional overturning circulation (AMOC), a more positive North Atlantic Oscillation (NAO) mode and a weakened Aleutian Low.

scholarly journals Sensitivity of Northern Hemisphere climate to ice-ocean interface heat flux parameterizations

2020 ◽  
Author(s):  
Xiaoxu Shi ◽  
Dirk Notz ◽  
Jiping Liu ◽  
Hu Yang ◽  
Gerrit Lohmann
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Sea Ice ◽  
Mixed Layer ◽  
Climate Model ◽  
Turbulent Heat Flux ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Turbulent Heat ◽  
Flux Parameterization

Abstract. We investigate the impact of three different parameterizations of ice-ocean heat exchange on modeled ice thickness, ice concentration, and water masses. These three parameterizations are (1) an ice-bath assumption with the ocean temperature fixed at the freezing temperature, (2) a turbulent heat-flux parameterization with ice-ocean heat exchange depending linearly on the temperature difference between the mixed layer and the ice-ocean interface, and (3) a similar turbulent heat-flux parameterization as (2) but with the temperature at the ice-ocean interface depending on ice-ablation rate. Based on model simulations with the standalone sea-ice model CICE, the ice-ocean model MPIOM and the climate model COSMOS, we find that (3) leads (in comparison to the other two parameterizations) to a thicker modeled sea ice, warmer water beneath high-concentration ice and cooler water towards the ice edge, and higher salinity in the Arctic Ocean mixed layer. Finally, in the fully coupled climate model COSMOS, the most realistic parameterization leads to an enhanced Atlantic meridional overturning circulation (AMOC), a more positive North Atlantic Oscillation (NAO) mode and a weakened Aleutian Low.

scholarly journals Multiyear sea ice thermal regimes and oceanic heat flux derived from an ice mass balance buoy in the Arctic Ocean

2014 ◽  
Vol 119 (1) ◽  
pp. 537-547 ◽  
Author(s):  
Ruibo Lei ◽  
Na Li ◽  
Petra Heil ◽  
Bin Cheng ◽  
Zhanhai Zhang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Mass Balance ◽  
The Arctic ◽  
Oceanic Heat Flux ◽  
Thermal Regimes ◽  
The Arctic Ocean ◽  
Ice Mass Balance

A comparison of factors that led to the extreme sea ice minima in the 21st century in the Arctic Ocean

2021 ◽  
pp. 1-56
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Atmospheric Circulation ◽  
21St Century ◽  
Open Water ◽  
The Arctic ◽  
Area Loss ◽  
The Arctic Ocean ◽  
The Difference

Abstract The extreme Arctic sea ice minima in the 21st century have been attributed to multiple factors, such as anomalous atmospheric circulation, excess solar radiation absorbed by open ocean, and thinning sea ice in a warming world. Most likely it is the combination of these factors that drive the extreme sea ice minima, but it has not been quantified, how the factors rank in setting the conditions for these events. To address this question, the sea ice budget of an Arctic regional sea ice-ocean model forced by atmospheric reanalysis data is analyzed to assess the development of the observed sea ice minima. Results show that the ice area difference in the years 2012, 2019, and 2007 is driven to over 60% by the difference in summertime sea ice area loss due to air-ocean heat flux over open water. Other contributions are small. For the years 2012 and 2020 the situation is different and more complex. The air-ice heat flux causes more sea ice area loss in summer 2020 than in 2012 due to warmer air temperatures, but this difference in sea ice area loss is compensated by reduced advective sea ice loss out of the Arctic Ocean mainly caused by the relaxation of the Arctic Dipole. The difference in open water area in early August leads to different air-ocean heat fluxes, which distinguishes the sea ice minima in 2012 and 2020. Further, sensitivity experiments indicate that both the atmospheric circulation associated with the Arctic Dipole and extreme storms are essential conditions for a new low record of sea ice extent.

scholarly journals Contribution of sea ice albedo and insulation effects to Arctic amplification in the EC-Earth Pliocene simulation

2019 ◽  
Vol 15 (1) ◽  
pp. 291-305 ◽  
Author(s):  
Jianqiu Zheng ◽  
Qiong Zhang ◽  
Qiang Li ◽  
Qiang Zhang ◽  
Ming Cai
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
Response Analysis ◽  
Turbulent Heat ◽  
Arctic Amplification ◽  
Sst Warming

Abstract. In the present work, we simulate the Pliocene climate with the EC-Earth climate model as an equilibrium state for the current warming climate induced by rising CO2 in the atmosphere. The simulated Pliocene climate shows a strong Arctic amplification featuring pronounced warming sea surface temperature (SST) over the North Atlantic, in particular over the Greenland Sea and Baffin Bay, which is comparable to geological SST reconstructions from the Pliocene Research, Interpretation and Synoptic Mapping group (PRISM; Dowsett et al., 2016). To understand the underlying physical processes, the air–sea heat flux variation in response to Arctic sea ice change is quantitatively assessed by a climate feedback and response analysis method (CFRAM) and an approach similar to equilibrium feedback assessment. Given the fact that the maximum SST warming occurs in summer while the maximum surface air temperature warming happens during winter, our analyses show that a dominant ice-albedo effect is the main reason for summer SST warming, and a 1 % loss in sea ice concentration could lead to an approximate 1.8 W m−2 increase in shortwave solar radiation into open sea surface. During the winter months, the insulation effect induces enhanced turbulent heat flux out of the sea surface due to sea ice melting in previous summer months. This leads to more heat released from the ocean to the atmosphere, thus explaining why surface air temperature warming amplification is stronger in winter than in summer.

scholarly journals Technical note: A sensitivity analysis from 1 to 40 GHz for observing the Arctic Ocean with the Copernicus Imaging Microwave Radiometer

2020 ◽  
Author(s):  
Lise Kilic ◽  
Catherine Prigent ◽  
Carlos Jimenez ◽  
Craig Donlon
Keyword(s):  
Sensitivity Analysis ◽  
Radiative Transfer ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Microwave Radiometer ◽  
Sea Surface ◽  
The Arctic ◽  
Transfer Model ◽  
The Arctic Ocean ◽  
Total Column

Abstract. The Copernicus Imaging Microwave Radiometer (CIMR) is one of the high priority missions for the expansion of the Copernicus program within the European Space Agency (ESA). It is designed to respond to the European Union Arctic policy. Its channels, incidence angle, precisions, and spatial resolutions have been selected to observe the Arctic Ocean with the recommendations expressed by the user communities. In this note, we present the sensitivity analysis that has led to the choice of the CIMR channels. The famous figure from Wilheit (1979), describing the frequency sensitivity of passive microwave satellite observations to ocean parameters, has been extensively used for channel selection of microwave radiometer frequencies on board oceanic satellite missions. Here, we propose to update this sensitivity analysis, using state-of-the-art radiative transfer simulations for different geophysical conditions (Arctic, mid-latitude, Tropics). We used the Radiative Transfer Model (RTM) from Meissner and Wentz (2012) for the ocean surface, the Round Robin Data Package of the ESA Climate Change Initiative (Pedersen et al., 2019) for the sea ice, and the RTM from Rosenkranz (2017) for the atmosphere. The sensitivities of the brightness temperatures (TBs) observed by CIMR as a function of Sea Surface Temperature (SST), Sea Surface Salinity (SSS), Sea Ice Concentration (SIC), Ocean Wind Speed (OWS), Total Column Water Vapor (TCWV), and Total Column Liquid Water (TCLW) are presented as a function of frequency between 1 to 40 GHz. The analysis underlines the difficulty to reach the user requirements with single channel retrieval, especially under cold ocean conditions. With simultaneous measurements between 1.4 and 36 GHz onboard CIMR, applying multi-channel algorithms will be facilitated, to provide the user community with the required ocean and ice information under arctic environments.

scholarly journals Technical note: A sensitivity analysis from 1 to 40 GHz for observing the Arctic Ocean with the Copernicus Imaging Microwave Radiometer

Ocean Science ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 455-461
Author(s):  
Lise Kilic ◽  
Catherine Prigent ◽  
Carlos Jimenez ◽  
Craig Donlon
Keyword(s):  
Sensitivity Analysis ◽  
Radiative Transfer ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Microwave Radiometer ◽  
Sea Surface ◽  
The Arctic ◽  
Transfer Model ◽  
The Arctic Ocean ◽  
Total Column

Abstract. The Copernicus Imaging Microwave Radiometer (CIMR) is one of the high-priority missions for the expansion of the Copernicus program within the European Space Agency (ESA). It is designed to respond to the European Union Arctic policy. Its channels, incidence angle, precision, and spatial resolutions have been selected to observe the Arctic Ocean with the recommendations expressed by the user communities. In this note, we present the sensitivity analysis that has led to the choice of the CIMR channels. The famous figure from Wilheit (1979), describing the frequency sensitivity of passive microwave satellite observations to ocean parameters, has been extensively used for channel selection of microwave radiometer frequencies on board oceanic satellite missions. Here, we propose to update this sensitivity analysis, using state-of-the-art radiative transfer simulations for different geophysical conditions (Arctic, mid-latitude, tropics). We used the Radiative Transfer Model (RTM) from Meissner and Wentz (2012) for the ocean surface, the Round Robin Data Package of the ESA Climate Change Initiative (Pedersen et al., 2019) for the sea ice, and the RTM from Rosenkranz (2017) for the atmosphere. The sensitivities of the brightness temperatures (TBs) observed by CIMR as a function of sea surface temperature (SST), sea surface salinity (SSS), sea ice concentration (SIC), ocean wind speed (OWS), total column water vapor (TCWV), and total column liquid water (TCLW) are presented as a function of frequency between 1 and 40 GHz. The analysis underlines the difficulty to reach the user requirements with single-channel retrieval, especially under cold ocean conditions. With simultaneous measurements between 1.4 and 36 GHz onboard CIMR, applying multi-channel algorithms will be facilitated, to provide the user community with the required ocean and ice information under arctic environments.

scholarly journals An Assessment of State-of-the-Art Mean Sea Surface and Geoid Models of the Arctic Ocean: Implications for Sea Ice Freeboard Retrieval

2017 ◽  
Vol 122 (11) ◽  
pp. 8593-8613 ◽  
Author(s):  
Henriette Skourup ◽  
Sinéad Louise Farrell ◽  
Stefan Hendricks ◽  
Robert Ricker ◽  
Thomas W. K. Armitage ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
State Of The Art ◽  
Sea Surface ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Mean Sea Surface
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