Variations in Atmospheric Energy Transport across the Arctic Circle

2021 ◽  
Author(s):  
Ines Höschel ◽  
Dörthe Handorf ◽  
Annette Rinke ◽  
Hélène Bresson
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Energy Transport ◽  
Lapse Rate ◽  
The Arctic ◽  
Arctic Amplification ◽  
Annual Average ◽  
Arctic Circle ◽  
Ice Melt ◽  
Static Energy

<p>Understanding the variability of energy transport and its components, and the mechanisms involved, is critical to improve our understanding of the Arctic amplification. Large amounts of energy are transported from the equator to the poles by the large-scale atmospheric circulation. At the Arctic Circle, this represents an annual average net transport of about two PW. The energy transport can be divided into latent and dry static components which, when increasing, indirectly contribute to the Arctic amplification. While the enhanced dry static energy transport favors sea ice melt and changes the lapse rate, the enhanced influx of latent energy affects the water vapor content and cloud formation, and thus also the lapse rate and sea ice melt via radiative effects.</p> <p>In this study, 40 years (1979-2018) of 6-hourly ERA-Interim reanalysis data are used to calculate the energy transport and its components. Inconsistencies due to spurious mass-flux are accounted for by barotropic wind field correction before the calculation. The first and last decade of the ERA-Interim period differ in terms of sea ice cover, sea surface temperature, and greenhouse gas concentrations, all of which affect the atmospheric circulation.</p> <p>The comparison between these periods shows significant changes in monthly and annual vertically integrated energy transport across the Arctic Circle. On an annual average, energy transport significantly increases in the late period for both total energy and its components, whereas the transport of dry static energy decreases in the winter season. The analysis of the atmospheric circulation reveals variations in the frequency of occurrence of preferred circulation regimes and the associated anomalies in energy transport as a potential cause for the observed changes.</p> <p>The hemispheric-scale and climatological view provides an expanded overall picture in terms of poleward energy transport to atmospheric events as cold air outbreaks and atmospheric rivers. This is demonstrated using the example of the atmospheric river which occurred over Svalbard on 6<sup>th</sup> & 7<sup>th</sup> June 2017.</p>

Linkage of Arctic Sea Ice and Energy Transport

2021 ◽  
Author(s):  
Ines Höschel ◽  
Dörthe Handorf ◽  
Christoph Jacobi ◽  
Johannes Quaas
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Energy Transport ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Moist Static Energy ◽  
Large Scale Circulation ◽  
Arctic Sea ◽  
Rossby Wave Propagation ◽  
Static Energy

<p>The loss of Arctic sea ice as a consequence of global warming is changing the forcing of the atmospheric large-scale circulation.  Areas not covered with sea ice anymore may act as an additional heat source.  Associated changes in Rossby wave propagation can initiate tropospheric and stratospheric pathways of Arctic - Mid-latitude linkages.  These pathways have the potential to impact on the large-scale energy transport into the Arctic.  On the other hand, studies show that the large-scale circulation contributes to Arctic warming by poleward transport of moist static energy. This presentation shows results from research within the Transregional Collaborative Research Center “ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3” funded by the Deutsche Forschungsgemeinschaft.  Using the ERA interim and ERA5 reanalyses the meridional moist static energy transport during high ice and low ice periods is compared.  The investigation discriminates between contributions from planetary and synoptic scale.  Special emphasis is put on the seasonality of the modulations of the large-scale energy transport.</p>

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.

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.

Arctic amplification as a rapid response to increased CO2

2021 ◽  
Author(s):  
Tyler Janoski ◽  
Michael Previdi ◽  
Gabriel Chiodo ◽  
Karen Smith ◽  
Lorenzo Polvani
Keyword(s):  
Sea Ice ◽  
General Circulation ◽  
Coupled Model ◽  
General Circulation Models ◽  
Forced Response ◽  
Arctic Sea Ice ◽  
Lapse Rate ◽  
The Arctic ◽  
Cmip5 Models ◽  
Arctic Amplification

<p>Arctic amplification (AA), or enhanced surface warming of the Arctic, is ubiquitous in observations, and in model simulations subjected to increased greenhouse gas (GHG) forcing. Despite its importance, the mechanisms driving AA are not entirely understood. Here, we show that in CMIP5 (Coupled Model Intercomparison Project 5) general circulation models (GCMs), AA develops within a few months following an instantaneous quadrupling of atmospheric CO<sub>2</sub>. We find that this rapid AA response can be attributed to the lapse rate feedback, which acts to disproportionately warm the Arctic, even before any significant changes in Arctic sea ice occur. Only on longer timescales (beyond the first few months) does the decrease in sea ice become an important contributor to AA via the albedo feedback and increased ocean-to-atmosphere heat flux. An important limitation of our CMIP5 analysis is that internal climate variability is large on the short time scales considered. To overcome this limitation – and thus better isolate the GHG-forced response – we produced a large ensemble (100 members) of instantaneous CO<sub>2</sub>-quadrupling simulations using a single GCM, the NCAR Community Earth System Model (CESM1). In our new CESM1 ensemble we find the same rapid AA response seen in the CMIP5 models, confirming that AA ultimately owes its existence to fast atmospheric processes.</p>

Impact of latent and dry-static atmospheric energy transport on the Arctic sea ice variability

2021 ◽  
Author(s):  
Marte G. Hofsteenge ◽  
Rune G. Graversen ◽  
Johanne H. Rydsaa
Keyword(s):  
Sea Ice ◽  
Energy Transport ◽  
Arctic Sea Ice ◽  
Planetary Waves ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Latent Energy ◽  
Arctic Sea ◽  
Ice Concentration ◽  
Static Energy

<p>Superimposed on a strong observed decline in Arctic sea ice extent there is large inter-annual variability. Recent research indicates that atmospheric temperature fluctuations are the main drivers for this variability. They can result both from local ocean heat release and from poleward atmospheric energy transport. Previous studies have emphasised a significant warming effect associated with latent energy transport into the Arctic region. In particular this is due to enhanced greenhouse effect associated with the convergence of the humidity transport over the Arctic. While previously some sea ice minima events have been linked to anomalous moist air convergence, a systematic study of this linkage between energy transport and sea ice variability was missing. Through a regression analysis we here investigate the coupling between transport anomalies of both latent and dry-static energy and sea ice anomalies. From the state-of-the-art ERA5 reanalysis product the latent and dry-static transport over the Arctic boundary (70°N) is calculated. The transport is then split into transport by planetary and synoptic-scale waves using a Fourier decomposition. Lagged regression analysis of sea ice concentration anomalies on the transport anomalies reveal the statistical linkage between the occurrence of sea ice anomalies after transport events. The results show that latent energy transport as compared to that of dry-static energy induces a much stronger decrease in sea ice concentration. One day after maximum of the latent transport event by planetary waves, sea-ice concentration shows a significant decrease lasting up to at least 45 days. In addition, the energy transport by planetary waves shows a greater effect on the sea ice concentration than transport by synoptic-scale waves. Hence, this study emphasizes the important impact of latent energy transport by planetary waves on the sea ice variability.</p>

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 Export of calcium carbonate corrosive waters from the East Siberian Sea

2016 ◽  
Author(s):  
Leif G. Anderson ◽  
Jörgen Ek ◽  
Ylva Ericson ◽  
Christoph Humborg ◽  
Igor Semiletov ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Ice ◽  
North Atlantic Ocean ◽  
The Arctic ◽  
High Pco2 ◽  
Low Oxygen ◽  
Saturation State ◽  
Ice Melt ◽  
The North ◽  
Transformation Of Organic Matter

Abstract. The Siberian Shelf Seas are areas of extensive biogeochemical transformation of organic matter, both of marine and terrestrial origin. This in combination with brine production from sea ice formation results in a cold bottom water of relative high salinity and partial pressure of carbon dioxide (pCO2). Data from the SWERUS-C3 expedition compiled on the icebreaker Oden in July to September 2014 show the distribution of such waters at the outer shelf, as well as their export into the deep central Arctic basins. Very high pCO2 water, up to close to 1000 µatm, was observed associated with high nutrients and low oxygen concentrations. Consequently the saturation state of calcium carbonate was low, down to less than 0.8 for calcite and 0.5 for aragonite. Waters undersaturated in aragonite were also observed in the surface in waters at equilibrium with atmospheric CO2, however, at these conditions the cause of under-saturation was low salinity from river runoff and/or sea ice melt. The calcium carbonate corrosive water was observed all along the continental margin and well out into the deep Makarov and Canada Basins at a depth from about 50 m depth in the west to about 150 m in the east. These waters of low aragonite saturation state are traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean north of Greenland and in the western Fram Strait, thus potentially impacting the marine life in the North Atlantic Ocean.

scholarly journals Sea ice melt pond fraction estimation from dual-polarisation C-band SAR – Part 2: Scaling in situ to Radarsat-2

2014 ◽  
Vol 8 (1) ◽  
pp. 845-885 ◽  
Author(s):  
R. K. Scharien ◽  
K. Hochheim ◽  
J. Landy ◽  
D. G. Barber
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Temporal Frequency ◽  
Model Performance ◽  
Free Water ◽  
Light Transmittance ◽  
The Arctic ◽  
Ice Melt ◽  
Melt Pond

Abstract. Observed changes in the Arctic have motivated efforts to understand and model its components as an integrated and adaptive system at increasingly finer scales. Sea ice melt pond fraction, an important summer sea ice component affecting surface albedo and light transmittance across the ocean-sea ice–atmosphere interface, is inadequately parameterized in models due to a lack of large scale observations. In this paper, results from a multi-scale remote sensing program dedicated to the retrieval of pond fraction from satellite C-band synthetic aperture radar (SAR) are detailed. The study was conducted on first-year sea (FY) ice in the Canadian Arctic Archipelago during the summer melt period in June 2012. Approaches to retrieve the subscale FY ice pond fraction from mixed pixels in RADARSAT-2 imagery, using in situ, surface scattering theory, and image data are assessed. Each algorithm exploits the dominant effect of high dielectric free-water ponds on the VV/HH polarisation ratio (PR) at moderate to high incidence angles (about 40° and above). Algorithms are applied to four images corresponding to discrete stages of the seasonal pond evolutionary cycle, and model performance is assessed using coincident pond fraction measurements from partitioned aerial photos. A RMSE of 0.07, across a pond fraction range of 0.10 to 0.70, is achieved during intermediate and late seasonal stages. Weak model performance is attributed to wet snow (pond formation) and synoptically driven pond freezing events (all stages), though PR has utility for identification of these events when considered in time series context. Results demonstrate the potential of wide-swath, dual-polarisation, SAR for large-scale observations of pond fraction with temporal frequency suitable for process-scale studies and improvements to model parameterizations.

scholarly journals Impacts of large-scale atmospheric circulation changes due to winter sea-ice retreat on Black Carbon transport and deposition to the Arctic

2016 ◽  
Author(s):  
Luca Pozzoli ◽  
Srdan Dobricic ◽  
Simone Russo ◽  
Elisabetta Vignati
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Large Scale ◽  
Southern Oscillation ◽  
The Arctic ◽  
The North ◽  
Ice Retreat ◽  
The North Atlantic Oscillation ◽  
Sea Ice Retreat

Abstract. Winter warming and sea ice retreat observed in the Arctic in the last decades determine changes of large scale atmospheric circulation pattern that may impact as well the transport of black carbon (BC) to the Arctic and its deposition on the sea ice, with possible feedbacks on the regional and global climate forcing. In this study we developed and applied a new statistical algorithm, based on the Maximum Likelihood Estimate approach, to determine how the changes of three large scale weather patterns (the North Atlantic Oscillation, the Scandinavian Blocking, and the El Nino-Southern Oscillation), associated with winter increasing temperatures and sea ice retreat in the Arctic, impact the transport of BC to the Arctic and its deposition. We found that the three atmospheric patterns together determine a decreasing winter deposition trend of BC between 1980 and 2015 in the Eastern Arctic while they increase BC deposition in the Western Arctic. The increasing trend is mainly due to the more frequent occurrences of stable high pressure systems (atmospheric blocking) near Scandinavia favouring the transport in the lower troposphere of BC from Europe and North Atlantic directly into to the Arctic. The North Atlantic Oscillation has a smaller impact on BC deposition in the Arctic, but determines an increasing BC atmospheric load over the entire Arctic Ocean with increasing BC concentrations in the upper troposphere. The El Nino-Southern Oscillation does not influence significantly the transport and deposition of BC to the Arctic. The results show that changes in atmospheric circulation due to polar atmospheric warming and reduced winter sea ice significantly impacted BC transport and deposition. The anthropogenic emission reductions applied in the last decades were, therefore, crucial to counterbalance the most likely trend of increasing BC pollution in the Arctic.

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