Meteorology and Transport of Air Masses in Arctic Regions

Stratospheric ozone in boreal fire plumes – the 2013 smoke season over central Europe

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-9631-2015 ◽

2015 ◽

Vol 15 (16) ◽

pp. 9631-9649 ◽

Cited By ~ 14

Author(s):

T. Trickl ◽

H. Vogelmann ◽

H. Flentje ◽

L. Ries

Keyword(s):

Stratospheric Ozone ◽

Conveyor Belt ◽

The Arctic ◽

Research Station ◽

Air Masses ◽

Elevated Ozone ◽

Arctic Regions ◽

Fire Plumes ◽

The Usa ◽

The Alps

Abstract. In July 2013 very strong boreal fire plumes were observed at the northern rim of the Alps by lidar and ceilometer measurements of aerosol, ozone and water vapour for about 3 weeks. In addition, some of the lower-tropospheric components of these layers were analysed at the Global Atmosphere Watch laboratory at the Schneefernerhaus high-altitude research station (2650 m a.s.l., located a few hundred metres south-west of the Zugspitze summit). The high amount of particles confirms our hypothesis that fires in the Arctic regions of North America lead to much stronger signatures in the central European atmosphere than the multitude of fires in the USA. This has been ascribed to the prevailing anticyclonic advection pattern during favourable periods and subsidence, in contrast to warm-conveyor-belt export, rainout and dilution frequently found for lower latitudes. A high number of the pronounced aerosol structures were positively correlated with elevated ozone. Chemical ozone formation in boreal fire plumes is known to be rather limited. Indeed, these air masses could be attributed to stratospheric air intrusions descending from remote high-latitude regions, obviously picking up the aerosol on their way across Canada. In one case, subsidence from the stratosphere over Siberia over as many as 15–20 days without increase in humidity was observed although a significant amount of Canadian smoke was trapped. These coherent air streams lead to rather straight and rapid transport of the particles to Europe.

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Elevated ozone in boreal fire plumes – the 2013 smoke season

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-13263-2015 ◽

2015 ◽

Vol 15 (9) ◽

pp. 13263-13313

Author(s):

T. Trickl ◽

H. Vogelmann ◽

H. Flentje ◽

L. Ries

Keyword(s):

The United States ◽

Conveyor Belt ◽

The Arctic ◽

Research Station ◽

Air Masses ◽

Elevated Ozone ◽

Arctic Regions ◽

Fire Plumes ◽

The Alps ◽

Air Streams

Abstract. In July 2013 very strong boreal fire plumes were observed at the northern rim of the Alps by lidar and ceilometer measurements of aerosol, ozone and water vapour for about three weeks. In addition, some of the lower-tropospheric components of these layers were analyzed at the Global Atmosphere Watch laboratory at the Schneefernerhaus high-altitude research station (2650 m a.s.l., located a few hundred metres south-west of the Zugspitze summit). The high amount of particles confirms our hypothesis that fires in the Arctic regions of North America have a much stronger impact on the Central European atmosphere than the multitude of fires in the United States. This has been ascribed to the prevailing anticyclonic advection pattern during favourable periods and subsidence, in contrast to warm-conveyor-belt export, rainout and dilution frequently found for lower latitudes. A high number of the pronounced aerosol structures were positively correlated with elevated ozone. Chemical ozone formation in boreal fire plumes is known to be rather limited. Indeed, these air masses could be attributed to stratospheric air intrusions over remote high latitude regions obviously picking up the aerosol on their way across Canada. In one case subsidence from the stratosphere over Siberia over as many as 15 to 20 days without increase in humidity was observed although a significant amount of Canadian smoke was trapped. These coherent air streams lead to rather straight and rapid transport of the particles to Europe.

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Elevated Potential Instability in the Comma Head: Distribution and Development

Monthly Weather Review ◽

10.1175/mwr-d-17-0283.1 ◽

2018 ◽

Vol 146 (4) ◽

pp. 1259-1278 ◽

Cited By ~ 2

Author(s):

Andrew A. Rosenow ◽

Robert M. Rauber ◽

Brian F. Jewett ◽

Greg M. McFarquhar ◽

Jason M. Keeler

Keyword(s):

Model Simulation ◽

Convective Available Potential Energy ◽

Wrf Model ◽

The Arctic ◽

Air Masses ◽

The North ◽

Arctic Regions ◽

The Pacific ◽

Central United States ◽

Convective Cells

The development of elevated potential instability within the comma head of a continental winter cyclone over the north-central United States is examined using a 63-h Weather Research and Forecasting (WRF) Model simulation. The simulation is first compared to the observed cyclone. The distribution of most unstable convective available potential energy (MUCAPE) within the comma head is then analyzed. The region with positive MUCAPE was based from 2- to 4-km altitude with MUCAPE values up to 93 J kg−1. Backward trajectories from five sublayers within the region of elevated convection in the comma head were calculated to investigate how elevated potential instability developed. Air in the lowest sublayer, the source air for convective cells, originated 63 h earlier near Baja California at elevations between 2.25- and 2.75-km altitude. Air atop the layer where convection occurred originated at altitudes between 9.25 and 9.75 km in the Arctic, 5000 km away from the origin of air in the lowest sublayer. All air in the layer in which convection occurred originated over the Pacific coast of Mexico, the Pacific Ocean, or arctic regions of Canada. Diabatic processes strongly influenced air properties during transit to the comma head. Air underwent radiative cooling, was affected by mixing during passage over mountains, and underwent interactions with clouds and precipitation. Notably, no trajectory followed an isentropic surface during the transit. The changes in thermodynamic properties along the trajectories led to an arrangement of air masses in the comma head that promoted the development of potential instability and elevated convection.

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Annual CO2 budget and seasonal CO2 exchange signals at a High Arctic permafrost site on Spitsbergen, Svalbard archipelago

Biogeosciences Discussions ◽

10.5194/bgd-11-1535-2014 ◽

2014 ◽

Vol 11 (1) ◽

pp. 1535-1559 ◽

Cited By ~ 3

Author(s):

J. Lüers ◽

S. Westermann ◽

K. Piel ◽

J. Boike

Keyword(s):

Biological Activity ◽

Net Ecosystem Exchange ◽

High Arctic ◽

Co2 Assimilation ◽

Co2 Exchange ◽

Svalbard Archipelago ◽

Air Masses ◽

Arctic Regions ◽

Flux Measurements ◽

Co2 Release

Abstract. The annual variability of CO2 exchange in most ecosystems is primarily driven by the activities of plants and soil microorganisms. However, little is known about the carbon balance and its controlling factors outside the growing season in arctic regions dominated by soil freeze/thaw-processes, long-lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a High Arctic tundra area on the west coast of Svalbard based on eddy-covariance flux measurements. The annual cumulative CO2 budget is close to zero grams carbon per square meter per year, but shows a very strong seasonal variability. Four major CO2 exchange seasons have been identified. (1) During summer (ground snow-free), the CO2 exchange occurs mainly as a result of biological activity, with a predominance of strong CO2 assimilation by the ecosystem. (2) The autumn (ground snow-free or partly snow-covered) is dominated by CO2 respiration as a result of biological activity. (3) In winter and spring (ground snow-covered), low but persistent CO2 release occur, overlain by considerable CO2 exchange events in both directions associated with changes of air masses and air and atmospheric CO2 pressure. (4) The snow melt season (pattern of snow-free and snow-covered areas), where both, meteorological and biological forcing, resulting in a visible carbon uptake by the high arctic ecosystem. Data related to this article are archived under: http://doi.pangaea.de/10.1594/PANGAEA.809507.

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Annual CO2 budget and seasonal CO2 exchange signals at a high Arctic permafrost site on Spitsbergen, Svalbard archipelago

Biogeosciences ◽

10.5194/bg-11-6307-2014 ◽

2014 ◽

Vol 11 (22) ◽

pp. 6307-6322 ◽

Cited By ~ 30

Author(s):

J. Lüers ◽

S. Westermann ◽

K. Piel ◽

J. Boike

Keyword(s):

Biological Activity ◽

Net Ecosystem Exchange ◽

High Arctic ◽

Co2 Assimilation ◽

Co2 Exchange ◽

Svalbard Archipelago ◽

Air Masses ◽

Arctic Regions ◽

Flux Measurements ◽

Co2 Release

Abstract. The annual variability of CO2 exchange in most ecosystems is primarily driven by the activities of plants and soil microorganisms. However, little is known about the carbon balance and its controlling factors outside the growing season in Arctic regions dominated by soil freeze/thaw processes, long-lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a high Arctic tundra area at the west coast of Svalbard based on eddy covariance flux measurements. The annual cumulative CO2 budget is close to 0 g C m−2 yr−1, but displays a strong seasonal variability. Four major CO2 exchange seasons have been identified. (1) During summer (snow-free ground), the CO2 exchange occurs mainly as a result of biological activity, with a dominance of strong CO2 assimilation by the ecosystem. (2) The autumn (snow-free ground or partly snow-covered) is dominated by CO2 respiration as a result of biological activity. (3) In winter and spring (snow-covered ground), low but persistent CO2 release occurs, overlayed by considerable CO2 exchange events in both directions associated with high wind speed and changes of air masses and atmospheric air pressure. (4) The snow melt season (pattern of snow-free and snow-covered areas) is associated with both meteorological and biological forcing, resulting in a carbon uptake by the high Arctic ecosystem. Data related to this article are archived at http://doi.pangaea.de/10.1594/PANGAEA.809507.

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