scholarly journals Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

2021 ◽  
pp. 1-44
Keyword(s):  
Heat Capacity ◽  
Sea Ice ◽  
Seasonal Pattern ◽  
Surface Heat ◽  
Lapse Rate ◽  
Effective Surface ◽  
Effective Heat Capacity ◽  
Arctic Warming ◽  
Rate Feedback ◽  
Effective Heat

Abstract Arctic surface warming under greenhouse gas forcing peaks in winter and reaches its minimum during summer in both observations and model projections. Many mechanisms have been proposed to explain this seasonal asymmetry, but disentangling these processes remains a challenge in the interpretation of general circulation model (GCM) experiments. To isolate these mechanisms, we use an idealized single-column sea ice model (SCM) which captures the seasonal pattern of Arctic warming. SCM experiments demonstrate that as sea ice melts and exposes open ocean, the accompanying increase in effective surface heat capacity can alone produce the observed pattern of peak warming in early winter (shifting to late winter under increased forcing) by slowing the seasonal heating rate, thus delaying the phase and reducing the amplitude of the seasonal cycle of surface temperature. To investigate warming seasonality in more complex models, we perform GCM experiments that individually isolate sea-ice albedo and thermodynamic effects under CO2 forcing. These also show a key role for the effective heat capacity of sea ice in promoting seasonal asymmetry through suppressing summer warming, in addition to precluding summer climatological inversions and a positive summer lapse-rate feedback. Peak winter warming in GCM experiments is further supported by a positive winter lapse-rate feedback, due to cold initial surface temperatures and strong surface-trapped warming that are enabled by the albedo effects of sea ice alone. While many factors contribute to the seasonal pattern of Arctic warming, these results highlight changes in effective surface heat capacity as a central mechanism supporting this seasonality.

scholarly journals Seasonality in Arctic Warming Driven By Sea Ice Effective Heat Capacity

2021 ◽  
Author(s):  
Lily Hahn ◽  
Kyle Armour ◽  
David Battisti ◽  
Ian Eisenman ◽  
Cecilia Bitz
Keyword(s):  
Heat Capacity ◽  
Sea Ice ◽  
Surface Heat ◽  
Lapse Rate ◽  
Early Winter ◽  
Effective Surface ◽  
Effective Heat Capacity ◽  
Arctic Warming ◽  
Winter Warming ◽  
Rate Feedback

Arctic surface warming under greenhouse gas forcing peaks in early winter and reaches its minimum during summer in both observations and model projections. Many mechanisms have been proposed to explain this seasonal asymmetry, but disentangling these processes remains a challenge in the interpretation of general circulation model (GCM) experiments. To isolate these mechanisms, we use an idealized single-column sea ice model (SCM) which captures the seasonal pattern of Arctic warming. SCM experiments demonstrate that as sea ice melts and exposes open ocean, the accompanying increase in effective surface heat capacity can alone produce the observed pattern of peak early winter warming by slowing the seasonal heating and cooling rate, thus delaying the phase and reducing the amplitude of the seasonal cycle of surface temperature. To investigate warming seasonality in more complex models, we perform GCM experiments that individually isolate sea-ice albedo and thermodynamic effects under CO2 forcing. These also show a key role for the effective heat capacity of sea ice in promoting seasonal asymmetry through suppressing summer warming, in addition to precluding summer climatological inversions and a positive summer lapse-rate feedback. Peak winter warming in GCM experiments is further supported by a positive winter lapse-rate feedback that persists with only the albedo effects of sea-ice loss prescribed, due to cold initial surface temperatures and strong surface-trapped warming. While many factors support peak early winter warming as Arctic sea ice declines, these results highlight changes in effective surface heat capacity as a central mechanism contributing to this seasonality.

scholarly journals Projected Changes in the Seasonal Cycle of Surface Temperature

2012 ◽  
Vol 25 (18) ◽  
pp. 6359-6374 ◽  
Author(s):  
John G. Dwyer ◽  
Michela Biasutti ◽  
Adam H. Sobel
Keyword(s):  
Heat Capacity ◽  
Sea Ice ◽  
Surface Temperature ◽  
Seasonal Cycle ◽  
Phase Delay ◽  
First Century ◽  
Effective Heat Capacity ◽  
Effective Heat ◽  
Twenty First Century ◽  
Global Mean

Abstract When forced with increasing greenhouse gases, global climate models project a delay in the phase and a reduction in the amplitude of the seasonal cycle of surface temperature, expressed as later minimum and maximum annual temperatures and greater warming in winter than in summer. Most of the global mean changes come from the high latitudes, especially over the ocean. All 24 Coupled Model Intercomparison Project phase 3 models agree on these changes and, over the twenty-first century, average a phase delay of 5 days and an amplitude decrease of 5% for the global mean ocean surface temperature. Evidence is provided that the changes are mainly driven by sea ice loss: as sea ice melts during the twenty-first century, the previously unexposed open ocean increases the effective heat capacity of the surface layer, slowing and damping the temperature response. From the tropics to the midlatitudes, changes in phase and amplitude are smaller and less spatially uniform than near the poles but are still prevalent in the models. These regions experience a small phase delay but an amplitude increase of the surface temperature cycle, a combination that is inconsistent with changes to the effective heat capacity of the system. The authors propose that changes in this region are controlled by changes in surface heat fluxes.

scholarly journals Sea ice and atmospheric circulation shape the high-latitude lapse rate feedback

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Nicole Feldl ◽  
Stephen Po-Chedley ◽  
Hansi K. A. Singh ◽  
Stephanie Hay ◽  
Paul J. Kushner
Keyword(s):  
Sea Ice ◽  
High Latitude ◽  
Energy Transport ◽  
Lower Troposphere ◽  
Longwave Radiation ◽  
Lapse Rate ◽  
Arctic Amplification ◽  
Albedo Feedback ◽  
Rate Feedback ◽  
Isentropic Surface

Abstract Arctic amplification of anthropogenic climate change is widely attributed to the sea-ice albedo feedback, with its attendant increase in absorbed solar radiation, and to the effect of the vertical structure of atmospheric warming on Earth’s outgoing longwave radiation. The latter lapse rate feedback is subject, at high latitudes, to a myriad of local and remote influences whose relative contributions remain unquantified. The distinct controls on the high-latitude lapse rate feedback are here partitioned into “upper” and “lower” contributions originating above and below a characteristic climatological isentropic surface that separates the high-latitude lower troposphere from the rest of the atmosphere. This decomposition clarifies how the positive high-latitude lapse rate feedback over polar oceans arises primarily as an atmospheric response to local sea ice loss and is reduced in subpolar latitudes by an increase in poleward atmospheric energy transport. The separation of the locally driven component of the high-latitude lapse rate feedback further reveals how it and the sea-ice albedo feedback together dominate Arctic amplification as a coupled mechanism operating across the seasonal cycle.

Effect of Brownian Motion and External Magnetic Field on the Effective Heat Capacity of Ferrofluids

2011 ◽  
Author(s):  
Narges Susan Mousavi Kh. ◽  
Sunil Kumar ◽  
Arvind Narayanaswamy
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Brownian Motion ◽  
Energy Equation ◽  
Volume Fraction ◽  
Physical Parameters ◽  
Effective Heat Capacity ◽  
Effective Heat ◽  
Negligible Contribution

An Eulerian formalism is used to derive the energy equation for a system of magnetic nanoparticles in a fluid (ferrofluid) in the presence of uniform magnetic field. The energy equation proposed here contains an effective heat capacity, which has contributions from: (1) Brownian motion of nanoparticles, (2) magnetic field, (3) temperature, and (4) volume fraction of particles. The modified term quantitatively shows the negligible contribution of the first three factors but the significant effect of concentration of particles in change in heat capacity of ferrofluid. In order to have a better understanding of the problem, the equation is converted to a non dimensional form from which the role of each of physical parameters can be inferred.

scholarly journals Stronger Arctic amplification from ozone-depleting substances than from carbon dioxide

2022 ◽  
Author(s):  
Yu-Chiao Liang ◽  
Lorenzo M. Polvani ◽  
Michael Previdi ◽  
Karen Louise Smith ◽  
Mark R. England ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Sea Ice ◽  
Climate Model ◽  
Montreal Protocol ◽  
Lapse Rate ◽  
The Arctic ◽  
Arctic Amplification ◽  
Near Surface ◽  
Arctic Warming ◽  
Ozone Depleting Substances

Abstract Arctic amplification (AA) - the greater warming of the Arctic near-surface temperature relative to its global mean value - is a prominent feature of the climate response to increasing greenhouse gases. Recent work has revealed the importance of ozone-depleting substances (ODS) in contributing to Arctic warming and sea-ice loss. Here, using ensembles of climate model integrations, we expand on that work and directly contrast Arctic warming from ODS to that from carbon dioxide (CO$_2$), over the 1955-2005 period when ODS loading peaked. We find that the Arctic warming and sea-ice loss from ODS are slightly more than half (52-59\%) those from CO$_2$. We further show that the strength of AA for ODS is 1.44 times larger than that for CO$_2$, and that this mainly stems from more positive Planck, albedo, lapse-rate, and cloud feedbacks. Our results suggest that AA would be considerably stronger than presently observed had the Montreal Protocol not been signed.

scholarly journals Temperature of a Temperate Glacier

1972 ◽  
Vol 11 (61) ◽  
pp. 15-29 ◽  
Author(s):  
W. D. Harrison
Keyword(s):  
Heat Capacity ◽  
Pure Water ◽  
Equilibrium Temperature ◽  
Water Soluble ◽  
Ice Thickness ◽  
Effective Heat Capacity ◽  
Effective Heat ◽  
Glacier Ice ◽  
Dominant Process ◽  
Definition Of

AbstractThe closure of water-filled glacier bore holes is considered and it is concluded that freezing due to conduction to the surrounding ice is usually the dominant process. On this basis englacial temperatures are obtained from a bore hole near the equilibrium line of Blue Glacier, U.S.A., where the ice thickness is about 125 m. Temperatures range from −0.03° C near the surface to −0.13° C at a depth of 105 m, with an estimated uncertainty of 0.02 or 0.03 deg. On the average the temperature is about 0.05 deg colder than the equilibrium temperature of ice and pure water. It is shown that at this temperature small amounts of water-soluble impurities play an important role in the thermal behavior of the ice. This leads to a new definition of temperate ice in terms of its effective heat capacity. The effective heat capacity of the Blue Glacier ice is apparently much larger than that of pure ice at the same temperature.

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