Comparison of experimentally observed long‐range horizontal under‐ice coherence in the Arctic with elastic scattering perturbation theory predictions.

1991 ◽  
Vol 90 (4) ◽  
pp. 2257-2257
Author(s):  
Henrik Schmidt ◽  
Kevin LePage ◽  
Eddie Scheer
Keyword(s):  
Perturbation Theory ◽  
Elastic Scattering ◽  
Long Range ◽  
The Arctic

Lunar landing and long-range earth re-entry guidance by application of perturbation theory

1964 ◽  
Vol 1 (2) ◽  
pp. 191-196 ◽  
Author(s):  
HENRY C. LESSING ◽  
PHILLIPS J. TUNNELL ◽  
ROBERT E. COATE
Keyword(s):  
Perturbation Theory ◽  
Long Range ◽  
Lunar Landing ◽  
Entry Guidance

scholarly journals New insights into aerosol and climate in the Arctic

2018 ◽  
Author(s):  
Jonathan P. D. Abbatt ◽  
W. Richard Leaitch ◽  
Amir A. Aliabadi ◽  
Alan K. Bertram ◽  
Jean-Pierre Blanchet ◽  
...  
Keyword(s):  
Long Range ◽  
Mineral Dust ◽  
Sea Surface ◽  
The Arctic ◽  
Long Range Transport ◽  
Surface Microlayer ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Range Transport ◽  
Warming World

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013 . (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water and the overlying atmosphere in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source. (2) Evidence was found of widespread particle nucleation and growth in the marine boundary layer in the CAA in the summertime. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from sea bird colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic material (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow.

scholarly journals Long range transmission loss of broadband seismic pulses in the Arctic under ice-free conditions

2010 ◽  
Vol 128 (4) ◽  
pp. EL181-EL187 ◽  
Author(s):  
Aaron Thode ◽  
Katherine H. Kim ◽  
Charles R. Greene ◽  
Ethan Roth
Keyword(s):  
Long Range ◽  
Transmission Loss ◽  
The Arctic

Dirty sea ice drives higher Mn concentrations in the Canada Basin

2021 ◽  
Author(s):  
Birgit Rogalla ◽  
Susan E. Allen ◽  
Manuel Colombo ◽  
Paul G. Myers ◽  
Kristin J. Orians
Keyword(s):  
Sea Ice ◽  
Long Range ◽  
Sediment Resuspension ◽  
Three Dimensional ◽  
Arctic Sea Ice ◽  
Canada Basin ◽  
The Arctic ◽  
Long Range Transport ◽  
Basin Surface ◽  
Range Transport

<p>The rapidly changing conditions of the Arctic sea ice system have cascading impacts on the biogeochemical cycles of the ocean. Sea ice transports sediments, nutrients, trace metals, pollutants, and gases from the extensive continental shelves into the more isolated central basins. However, it is difficult to assess the net contribution of this supply mechanism on nutrients in the surface ocean. In this study, we used Manganese (Mn), a micronutrient and tracer which can integrate source fluctuations in space and time, to understand the net impact of the long range transport of sea ice for Mn.</p><p>We developed a three-dimensional dissolved Mn model within a subdomain of the 1/12 degree Arctic and Northern Hemispheric Atlantic (ANHA12) configuration of NEMO centred on the Canadian Arctic Archipelago, and evaluated this model with in situ observations from the 2015 Canadian GEOTRACES cruises. The Mn model incorporates parameterizations for the contributions from river discharge, sediment resuspension, atmospheric deposition of aerosols directly to the ocean and via melt from sea ice, release of sediment from sea ice, and reversible scavenging, while the NEMO-TOP engine takes care of the advection and diffusion of the tracers. </p><p>Simulations with this model from 2002 to 2019 indicate that the majority of external Mn contributed annually to the Canada Basin surface is released by sediment from sea ice, much of which originates from the Siberian shelves. Reduced sea ice longevity in the Siberian shelf regions has been postulated to result in the disruption of the long range transport of sea ice by the transpolar drift. This reduced sea ice supply has the potential to decrease the Canada Basin Mn surface maximum and downstream Mn supply, with implications for other nutrients (such as Fe) contained in ice-rafted sediments as well. These results demonstrate some of the many changes to the biogeochemical supply mechanisms expected in the near-future in the Arctic Ocean and the subpolar seas.</p>

The role of sea ice for plastic pollution in the Arctic

2021 ◽  
Author(s):  
Ilka Peeken ◽  
Elisa Bergami ◽  
Ilaria Corsi ◽  
Benedikt Hufnagl ◽  
Christian Katlein ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Long Range ◽  
Environmental Concern ◽  
Ice Cores ◽  
Atlantic Water ◽  
The Arctic ◽  
Polar Regions ◽  
Plastic Pollution ◽  
The Arctic Ocean

<p>Marine plastic pollution is a growing worldwide environmental concern as recent reports indicate that increasing quantities of litter disperse into secluded environments, including Polar Regions. Plastic degrades into smaller fragments under the influence of sunlight, temperature changes, mechanic abrasion and wave action resulting in small particles < 5mm called microplastics (MP). Sea ice cores, collected in the Arctic Ocean have so far revealed extremely high concentrations of very small microplastic particles, which might be transferred in the ecosystem with so far unknown consequences for the ice dependant marine food chain.  Sea ice has long been recognised as a transport vehicle for any contaminates entering the Arctic Ocean from various long range and local sources. The Fram Strait is hereby both, a major inflow gateway of warm Atlantic water, with any anthropogenic imprints and the major outflow region of sea ice originating from the Siberian shelves and carried via the Transpolar Drift. The studied sea ice revealed a unique footprint of microplastic pollution, which were related to different water masses and indicating different source regions. Climate change in the Arctic include loss of sea ice, therefore, large fractions of the embedded plastic particles might be released and have an impact on living systems. By combining modeling of sea ice origin and growth, MP particle trajectories in the water column as well as MPs long-range transport via particle tracking and transport models we get first insights  about the sources and pathways of MP in the Arctic Ocean and beyond and how this might affect the Arctic ecosystem.</p>

scholarly journals Overview paper: New insights into aerosol and climate in the Arctic

2019 ◽  
Vol 19 (4) ◽  
pp. 2527-2560 ◽  
Author(s):  
Jonathan P. D. Abbatt ◽  
W. Richard Leaitch ◽  
Amir A. Aliabadi ◽  
Allan K. Bertram ◽  
Jean-Pierre Blanchet ◽  
...  
Keyword(s):  
Long Range ◽  
Mineral Dust ◽  
Sea Surface ◽  
The Arctic ◽  
Long Range Transport ◽  
Surface Microlayer ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Range Transport ◽  
Warming World

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water (up to 75 nM) and the overlying atmosphere (up to 1 ppbv) in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source (with DMS concentrations of up to 6 nM and a potential contribution to atmospheric DMS of 20 % in the study area). (2) Evidence of widespread particle nucleation and growth in the marine boundary layer was found in the CAA in the summertime, with these events observed on 41 % of days in a 2016 cruise. As well, at Alert, Nunavut, particles that are newly formed and grown under conditions of minimal anthropogenic influence during the months of July and August are estimated to contribute 20 % to 80 % of the 30–50 nm particle number density. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from seabird-colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic aerosol (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds (OVOCs) were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms, with evidence for a dominant springtime contribution from eastern and southern Asia to the middle troposphere, and a major contribution from northern Asia to the surface. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow (0.03 cm s−1).

scholarly journals Vibrational lifetimes and friction in adsorbate motion determined from quasi-elastic scattering

2015 ◽  
Vol 17 (34) ◽  
pp. 21819-21823 ◽  
Author(s):  
Barbara A. J. Lechner ◽  
Holly Hedgeland ◽  
Andrew P. Jardine ◽  
William Allison ◽  
B. J. Hinch ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Helium Atom ◽  
Long Range ◽  
Helium Atom Scattering ◽  
Adsorbate Molecule ◽  
Atom Scattering ◽  
Quasi Elastic Scattering

The vibrations of an adsorbate molecule are measured by quasi-elastic helium atom scattering at the same time as long-range diffusion.

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