Changes in atmospheric latent energy transport into the Arctic; planetary versus synoptic scales

Arctic climate response to extreme events in synoptic and planetary scale atmospheric energy transport

10.5194/egusphere-egu2020-21344 ◽

2020 ◽

Author(s):

Johanne H. Rydsaa ◽

Rune G. Graversen ◽

Patrick Stoll

Keyword(s):

Energy Transport ◽

Winter Season ◽

Arctic Climate ◽

The Arctic ◽

Synoptic Scale ◽

Near Surface ◽

Latent Energy ◽

Atmospheric Energy ◽

Planetary Scale ◽

Atmospheric Energy Transport

Atmospheric energy transport into the Arctic (>70&#176; N) has been shown to greatly alter the Arctic temperatures and the development of the Arctic weather and climate. Recent research suggests that latent energy transport into the Arctic by large, planetary-scale atmospheric systems cause a stronger and more long-lasting impact on near surface temperatures, than energy transported by smaller, synoptic scale systems. This implies that Rossby waves impact Arctic climate more than synoptic cyclones. Therefore, shifts in circulation patterns driving atmospheric energy transport into the Arctic on different scales have a potential to change Arctic climate.Here, we show that the annual mean impact of latent energy transport on Arctic temperatures is dominated by the winter season transport. Furthermore, by examining the ERA5 dataset for the years 1979-2018, we find that over the past four decades, there has been a shift in the mean winter season latent energy transport, from smaller, synoptic scale systems (-0.03 PW/decade), towards larger, planetary scale systems (+0.05 PW/decade) which as mentioned, have a larger climatic impact. As a consequence, this shift is estimated to have increased the Arctic temperatures. We find that the trends are driven by an increase in the extreme transport events (here we examine the upper 97.5th percentile). The upper extremes have increased more than the average on the planetary scale, and decreased more on the synoptic scale. The decrease in extreme synoptic scale transport at 70&#176; N has been confirmed in other analyses of high vorticity weather systems. By examining the extreme transport events on seasonal scales, we reveal differences in the temporal distribution of planetary vs. synoptic scale extreme events, and identify areas of the Arctic that receive the strongest impact with respect to increases in near-surface temperatures.

The Impact of Atmospheric Rossby Waves and Cyclones On The Arctic Sea Ice Variability

10.21203/rs.3.rs-826962/v1 ◽

2021 ◽

Author(s):

Marte Gé Hofsteenge ◽

Rune Grand Graversen ◽

Johanne Hope Rydsaa ◽

Zoé Rey

Keyword(s):

Sea Ice ◽

Energy Transport ◽

Rossby Waves ◽

Arctic Sea Ice ◽

The Arctic ◽

Synoptic Scale ◽

Sea Ice Concentration ◽

Latent Energy ◽

Arctic Sea ◽

Ice Concentration

Abstract The Arctic sea-ice extent has strongly declined over recent decades. A large inter-annual variability is superimposed on this negative trend. Previous studies have emphasised a significant warming effect associated with latent energy transport into the Arctic region, in particular due to an enhanced greenhouse effect associated with the convergence of the humidity transport over the Arctic. The atmospheric energy transport into the Arctic is mostly accomplished by waves such as Rossby waves and cyclones. Here we present a systematic study of the effect on Arctic sea ice of these atmospheric wave types. Through a regression analysis we 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 ºN) is calculated. The transport is then split into transport by planetary and synoptic-scale waves using a Fourier decomposition. The results show that latent energy transport as compared to that of dry-static shows a much stronger potential to decrease sea ice concentration. However, taking into account that the variability of dry-static transport is of an order of magnitude larger than latent, the actual impact on the sea ice appears similar for the two components. In addition, the energy transport by planetary waves causes a strong decline of the sea ice concentration whereas the transport by synoptic-scale waves shows only little effect on the sea ice. The study emphasises the importance of the large-scale waves on the sea ice variability.

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

10.5194/egusphere-egu21-6594 ◽

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

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&#176;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.

How Asian aerosols impact regional surface temperatures across the globe

10.5194/acp-2020-1029 ◽

2020 ◽

Author(s):

Joonas Merikanto ◽

Kalle Nordling ◽

Petri Räisänen ◽

Jouni Räisänen ◽

Declan O'Donnell ◽

...

Keyword(s):

Surface Temperature ◽

Temperature Effects ◽

Energy Transport ◽

Temperature Response ◽

The Arctic ◽

Anthropogenic Aerosols ◽

Atmospheric Energy ◽

Atmospheric Energy Transport ◽

Temperature Responses ◽

Global Surface

Abstract. South and East Asian anthropogenic aerosols mostly reside in an air mass extending from the Indian Ocean to the North Pacific. Yet the surface temperature effects of Asian aerosols spread across the whole globe. Here, we remove Asian anthropogenic aerosols from two independent climate models (ECHAM6.1 and NorESM1) using the same representation of aerosols via MACv2-SP (a simple plume implementation of the 2nd version of the Max Planck Institute Aerosol Climatology). We then robustly decompose the global distribution of surface temperature responses into contributions from atmospheric energy flux changes. We find that the horizontal atmospheric energy transport strongly moderates the surface temperature response over the regions where Asian aerosols reside. Atmospheric energy transport and changes in clear-sky longwave radiation redistribute the temperature effects efficiently across the Northern hemisphere, and to a lesser extent also over the Southern hemisphere. The model-mean global surface temperature response to Asian anthropogenic aerosol removal is 0.26 ± 0.04 °C (0.22 ± 0.03 for ECHAM6.1 and 0.30 ± 0.03 °C for NorESM1) of warming. Model-to-model differences in global surface temperature response mainly arise from differences in longwave cloud (0.01 ± 0.01 for ECHAM6.1 and 0.05 ± 0.01 °C for NorESM1) and shortwave cloud (0.03 ± 0.03 for ECHAM6.1 and 0.07 ± 0.02 °C for NorESM1) responses. The differences in cloud responses between the models also dominate the differences in regional temperature responses. In both models, the Northern hemispheric surface warming amplifies towards the Arctic, where the total temperature response is highly seasonal and weakest during the Arctic summer. We estimate that under a strong Asian aerosol mitigation policy tied with strong climate mitigation (Shared Socioeconomic Pathway 1-1.9) the Asian aerosol reductions can add around 8 years' worth of current day global warming during the next few decades.

TRANSARCTIC PERSPECTIVES OF IBERO-AMERICA

EurasianUnionScientists ◽

10.31618/esu.2413-9335.2020.6.73.687 ◽

2020 ◽

Vol 6 (4(73)) ◽

pp. 36-39

Author(s):

E.O. Labeckaya

Keyword(s):

Russian Federation ◽

Energy Transport ◽

The Arctic ◽

Global Competition ◽

Arctic Zone ◽

Case Study Method ◽

The Russian Federation ◽

Transnational Space

Through the concept of transnational space and “case-study” method, the prospects for the involvement of Ibero-America in the virtual Trans-Arctic, which is turning into a geoeconomic and geopolitical "bond" of two neighboring spaces – Trans-Atlantic and Trans-Pacific – are considered. The strengthening of Iberoamerican states’ presence in the Trans-Arctic will be a factor in increasing their ratings in the global hierarchy, will provide them with new geopolitical advantages for global competition, will strengthen comprehensive security (economic, environmental, energy, transport and logistics, food, water). In the context of the Arctic interests of Ibero-America, special attention is paid to options for possible "win-win" cooperation in the Arctic zone of the Russian Federation, including taking into account the potential of BRICS and its "outreach" and "BRICS +" platforms. Highlighted fundamental legal differences between Trans-Arctic and Antarctic. The Arctic prospects of Brazil as a channel for the realization of the circumpolar interests of the Iberoamerican states are emphasized

Linkage of Arctic Sea Ice and Energy Transport

10.5194/egusphere-egu21-2057 ◽

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

The loss of Arctic sea ice as a consequence of global warming is changing the forcing of the atmospheric large-scale circulation. &#160;Areas not covered with sea ice anymore may act as an additional heat source. &#160;Associated changes in Rossby wave propagation can initiate tropospheric and stratospheric pathways of Arctic - Mid-latitude linkages.&#160; These pathways have the potential to impact on the large-scale energy transport into the Arctic.&#160; 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 &#8220;ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3&#8221; funded by the Deutsche Forschungsgemeinschaft.&#160; Using the ERA interim and ERA5 reanalyses the meridional moist static energy transport during high ice and low ice periods is compared. &#160;The investigation discriminates between contributions from planetary and synoptic scale.&#160; Special emphasis is put on the seasonality of the modulations of the large-scale energy transport.

The Changing Energy Balance of the Polar Regions in a Warmer Climate

Journal of Climate ◽

10.1175/jcli-d-12-00233.1 ◽

2013 ◽

Vol 26 (10) ◽

pp. 3112-3129 ◽

Cited By ~ 9

Author(s):

Lennart Bengtsson ◽

Kevin I. Hodges ◽

Symeon Koumoutsaris ◽

Matthias Zahn ◽

Paul Berrisford

Keyword(s):

Polar Region ◽

Energy Transport ◽

Climate Model ◽

Radiant Energy ◽

Surface Radiation ◽

The Arctic ◽

Polar Regions ◽

Energy Fluxes ◽

Intergovernmental Panel ◽

Static Energy

Abstract Energy fluxes for polar regions are examined for two 30-yr periods, representing the end of the twentieth and twenty-first centuries, using data from high-resolution simulations with the ECHAM5 climate model. The net radiation to space for the present climate agrees well with data from the Clouds and the Earth’s Radiant Energy System (CERES) over the northern polar region but shows an underestimation in planetary albedo for the southern polar region. This suggests there are systematic errors in the atmospheric circulation or in the net surface energy fluxes in the southern polar region. The simulation of the future climate is based on the Intergovernmental Panel on Climate Change (IPCC) A1B scenario. The total energy transport is broadly the same for the two 30-yr periods, but there is an increase in the moist energy transport on the order of 6 W m−2 and a corresponding reduction in the dry static energy. For the southern polar region the proportion of moist energy transport is larger and the dry static energy correspondingly smaller for both periods. The results suggest a possible mechanism for the warming of the Arctic that is discussed. Changes between the twentieth and twenty-first centuries in the northern polar region show the net ocean surface radiation flux in summer increases ~18 W m−2 (24%). For the southern polar region the response is different as there is a decrease in surface solar radiation. It is suggested that this is caused by changes in cloudiness associated with the poleward migration of the storm tracks.

The effect of latent heat transport by waves on Greenland Surface Mass Balance

10.5194/egusphere-egu2020-7006 ◽

2020 ◽

Author(s):

Tuomas Ilkka Henrikki Heiskanen ◽

Rune Grand Graversen

Keyword(s):

Mass Balance ◽

Heat Transport ◽

Latent Heat ◽

Energy Transport ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

The Arctic ◽

Surface Mass Balance ◽

Surface Mass ◽

Circulation Patterns

The Arctic region shows some of the world's most significant signs of climate change. The atmospheric energy transport plays an important role for the Arctic climate; the atmospheric transport contributes an amount of energy into the Arctic that is comparable to that provided directly by the sun. From recently developed Fourier and wavelet based methods it has been found that the planetary component of the latent heat transport affects that Arctic surface temperatures stronger than the decomposed dry-static energy transport and the synoptic scale component of the latent heat transport.&#160;A large concern for humanity is that the climate change in polar regions will lead to significant melting of the ice sheets and glaciers. In fact the discharge water from the Greenland ice sheet has recently increased to the extent that this ice sheet is one of the major contributorsto sea-level rise. Here we test the hypothesis that the recent rapid increase in melt of the Greenland ice sheet is linked to a shift of planetary-scale waves transporting warm and humid air over the ice sheet.The effect of the atmospheric energy transport is investigated by correlating the divergence of energy over the Greenland ice sheet with the surface mass balance of this ice sheet. The divergence of latent heat transport is found to correlate positively with the surface mass balance along the edges of the ice sheet, and negatively in the interior. This indicates that a convergence of latent at the edges of the ice sheet lead to a increased mass discharge from the ice sheet, whilst in the interior converging latent heat indicates an accumulation of mass to the ice sheet.&#160;To investigate the effect of transport by planetary and synoptic scale waves on the Greenland ice sheet surface mass balance the mass flux component of the transport divergence is decomposed into wavenumbers through the application of a Fourier series. The divergences of transport contributions of each wavenumber are then correlated with the surface mass balance of the Greenland ice sheet. The correlations between the surface-mass balance and divergence of transport contributions by different wavenumbers reveals the relative impact of atmospheric circulation systems, such as Rossby waves and cyclones, on the Greenland ice sheet mass balance. Further, identifying shifts in the circulation patterns over Greenland by applying self organizing maps, or similar methods, and investigations of how these circulation patterns affect the energy transport over Greenland by atmospheric waves of different scales are also pursued. &#160; &#160;&#160;

Cloud Effects on the Meridional Atmospheric Energy Budget Estimated from Clouds and the Earth’s Radiant Energy System (CERES) Data

Journal of Climate ◽

10.1175/2008jcli1982.1 ◽

2008 ◽

Vol 21 (17) ◽

pp. 4223-4241 ◽

Cited By ~ 15

Author(s):

Seiji Kato ◽

Fred G. Rose ◽

David A. Rutan ◽

Thomas P. Charlock

Keyword(s):

Energy Transport ◽

Radiant Energy ◽

Energy System ◽

The Arctic ◽

Polar Regions ◽

Radiative Effect ◽

Cloud Radiative Effect ◽

Cloud Effect ◽

The Difference ◽

The Tropics

Abstract The zonal mean atmospheric cloud radiative effect, defined as the difference between the top-of-the-atmosphere (TOA) and surface cloud radiative effects, is estimated from 3 yr of Clouds and the Earth’s Radiant Energy System (CERES) data. The zonal mean shortwave effect is small, though it tends to be positive (warming). This indicates that clouds increase shortwave absorption in the atmosphere, especially in midlatitudes. The zonal mean atmospheric cloud radiative effect is, however, dominated by the longwave effect. The zonal mean longwave effect is positive in the tropics and decreases with latitude to negative values (cooling) in polar regions. The meridional gradient of the cloud effect between midlatitude and polar regions exists even when uncertainties in the cloud effect on the surface enthalpy flux and in the modeled irradiances are taken into account. This indicates that clouds increase the rate of generation of the mean zonal available potential energy. Because the atmospheric cooling effect in polar regions is predominately caused by low-level clouds, which tend to be stationary, it is postulated here that the meridional and vertical gradients of the cloud effect increase the rate of meridional energy transport by the dynamics of the atmosphere from the midlatitudes to the polar region, especially in fall and winter. Clouds then warm the surface in the polar regions except in the Arctic in summer. Clouds, therefore, contribute toward increasing the rate of meridional energy transport from the midlatitudes to the polar regions through the atmosphere.

Variations in Atmospheric Energy Transport across the Arctic Circle

10.5194/dach2022-124 ◽

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

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. 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. 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. 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 6th & 7th June 2017.