An Arctic source for the great salinity anomaly: A simulation of the Arctic ice-ocean system for 1955–1975

1993 ◽  
Vol 98 (C9) ◽  
pp. 16397 ◽  
Author(s):  
Sirpa Häkkinen
Keyword(s):  
The Arctic ◽  
Salinity Anomaly ◽  
Great Salinity Anomaly ◽  
Arctic Ice

scholarly journals Mechanisms behind the Temporary Shutdown of Deep Convection in the Labrador Sea: Lessons from the Great Salinity Anomaly Years 1968–71

2012 ◽  
Vol 25 (19) ◽  
pp. 6743-6755 ◽  
Author(s):  
Renske Gelderloos ◽  
Fiammetta Straneo ◽  
Caroline A. Katsman
Keyword(s):  
Greenland Ice Sheet ◽  
The Arctic ◽  
Subsurface Water ◽  
Labrador Sea ◽  
Freshwater Flux ◽  
Atmospheric Forcing ◽  
Tight Coupling ◽  
Positive Feedbacks ◽  
Salinity Anomaly ◽  
Great Salinity Anomaly

Abstract From 1969 to 1971 convection in the Labrador Sea shut down, thus interrupting the formation of the intermediate/dense water masses. The shutdown has been attributed to the surface freshening induced by the Great Salinity Anomaly (GSA), a freshwater anomaly in the subpolar North Atlantic. The abrupt resumption of convection in 1972, in contrast, is attributed to the extreme atmospheric forcing of that winter. Here oceanic and atmospheric data collected in the Labrador Sea at Ocean Weather Station Bravo and a one-dimensional mixed layer model are used to examine the causes of the shutdown and resumption of convection in detail. These results highlight the tight coupling of the ocean and atmosphere in convection regions and the need to resolve both components to correctly represent convective processes in the ocean. They are also relevant to present-day conditions given the increased ice melt in the Arctic Ocean and from the Greenland Ice Sheet. The analysis herein shows that the shutdown was initiated by the GSA-induced freshening as well as the mild 1968/69 winter. After the shutdown had begun, however, the continuing lateral freshwater flux as well as two positive feedbacks [both associated with the sea surface temperature (SST) decrease due to lack of convective mixing with warmer subsurface water] further inhibited convection. First, the SST decrease reduced the heat flux to the atmosphere by reducing the air–sea temperature gradient. Second, it further reduced the surface buoyancy loss by reducing the thermal expansion coefficient of the surface water. In 1972 convection resumed because of both the extreme atmospheric forcing and advection of saltier waters into the convection region.

scholarly journals The influence of the lunar nodal cycle on Arctic climate

2006 ◽  
Vol 63 (3) ◽  
pp. 401-420 ◽  
Author(s):  
Harald Yndestad
Keyword(s):  
Time Series ◽  
Signal To Noise Ratio ◽  
Phase Relationship ◽  
Harmonic Spectrum ◽  
Arctic Climate ◽  
The Arctic ◽  
Major Influence ◽  
Sea Temperature ◽  
Arctic Ice

Abstract The Arctic Ocean is a substantial energy sink for the northern hemisphere. Fluctuations in its energy budget will have a major influence on the Arctic climate. The paper presents an analysis of the time-series for the polar position, the extent of Arctic ice, sea level at Hammerfest, Kola section sea temperature, Røst winter air temperature, and the NAO winter index as a way to identify a source of dominant cycles. The investigation uses wavelet transformation to identify the period and the phase in these Arctic time-series. System dynamics are identified by studying the phase relationship between the dominant cycles in all time-series. A harmonic spectrum from the 18.6-year lunar nodal cycle in the Arctic time-series has been identified. The cycles in this harmonic spectrum have a stationary period, but not stationary amplitude and phase. A sub-harmonic cycle of about 74 years may introduce a phase reversal of the 18.6-year cycle. The signal-to-noise ratio between the lunar nodal spectrum and other sources changes from 1.6 to 3.2. A lunar nodal cycle in all time-series indicates that there is a forced Arctic oscillating system controlled by the pull of gravity from the moon, a system that influences long-term fluctuations in the extent of Arctic ice. The phase relation between the identified cycles indicates a possible chain of events from lunar nodal gravity cycles, to long-term tides, polar motions, Arctic ice extent, the NAO winter index, weather, and climate.

Backbone for Escape, Evacuation and Rescue From Arctic Facilities: A Systematic Approach

2014 ◽  
Author(s):  
Mark Longrée ◽  
Sven Hoog
Keyword(s):  
Energy Demand ◽  
Oil And Gas ◽  
Tourism Industry ◽  
The Arctic ◽  
Joint Research ◽  
Operating Personnel ◽  
Gas Industry ◽  
Joint Research Project ◽  
Arctic Ice ◽  
The Impact

In turn of the global warming and driven by the constant need for resources an increasing number of commercial and scientific activities conquer the Arctic in order to benefit from almost untouched resources like oil and gas but also from the overwhelming nature. These activities are accompanied by a steadily increasing number of vessels transporting goods but also operating personnel, scientists or tourists. Especially the number of tourists visiting the Arctic can reach far more than 1000 per vessel, resulting in growing headaches for the responsible safety and security authorities in the Arctic surrounding countries. Up to now no suitable Escape, Evacuation and Rescue (EER) concept is in place to cope with these challenges when it comes to hazardous situations. In this context IMPaC ([1]) developed a new and appropriate EER concept for the Arctic, exceeding the currently dominant small and isolated settlements along the coastlines in Denmark (Greenland), Norway, Russia, Canada and the US. One question seems to be central: Is there any requirement and benefit beyond the currently used small rescue station? Yes, we strongly believe that there is a growing demand for suitable infrastructure coming from various industries. Beyond rescue objectives there is a demand for people working and living in this area all year long, for a few days, weeks or months using these settlements for their specific needs. This led us to the idea of the provision of a common-use infrastructure for multiple industries. The commonly used infrastructure maximizes the use of the remote and very expensive infrastructure and minimizes the impact on the environment in this part of the world. Potential users of this infrastructure would be: • Oil & Gas Industry, driven by the increased world energy demand • Marine Transport & Tourism Industry, driven by declined arctic ice and new sea routes via the Arctic sea • Fishery Industry • Scientific community Any EER concept for the Arctic has to cope with several specific environmental and spatial challenges as addressed by the EU joint research project ACCESS ([2]), where IMPaC participates. The paper introduces the new EER concept and focuses especially on its beneficial, efficient and safe operability in the Arctic recording an increasing number of commercial and scientific activities.

scholarly journals Correlation and trend studies of the sea-ice cover and surface temperatures in the Arctic

2002 ◽  
Vol 34 ◽  
pp. 420-428 ◽  
Author(s):  
Josefino C. Comiso
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Ice Cover ◽  
The Arctic ◽  
Temperature Anomalies ◽  
Ice Concentration ◽  
Arctic Ice ◽  
Highly Correlated ◽  
Surface Ice ◽  
Perennial Ice

AbstractCo-registered and continuous satellite data of sea-ice concentrations and surface ice temperatures from 1981 to 2000 are analyzed to evaluate relationships between these two critical climate parameters and what they reveal in tandem about the changing Arctic environment. During the 19 year period, the Arctic ice extent and actual ice area are shown to be declining at a rate of –2.0±0.3% dec –1 and 3.1 ±0.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.4 ±0.2 K dec–1, where dec is decade. The extent and area of the perennial ice cover, estimated from summer minimum values, have been declining at a much faster rate of –6.7±2.4% dec–1 and –8.3±2.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.9 ±0.6K dec–1. This unusual rate of decline is accompanied by a very variable summer ice cover in the 1990s compared to the 1980s, suggesting increases in the fraction of the relatively thin second-year, and hence a thinning in the perennial, ice cover during the last two decades. Yearly anomaly maps show that the ice-concentration anomalies are predominantly positive in the 1980s and negative in the 1990s, while surface temperature anomalies were mainly negative in the 1980s and positive in the 1990s. The yearly ice-concentration and surface temperature anomalies are highly correlated, indicating a strong link especially in the seasonal region and around the periphery of the perennial ice cover. The surface temperature anomalies also reveal the spatial scope of each warming (or cooling) phenomenon that usually extends beyond the boundaries of the sea-ice cover.

The use of Cs and Sr isotopes as tracers in the Arctic Mediterranean Seas

1988 ◽  
Vol 325 (1583) ◽  
pp. 161-176 ◽  
Keyword(s):  
Deep Water ◽  
Thermohaline Circulation ◽  
Atlantic Water ◽  
The Arctic ◽  
Coastal Current ◽  
Intermediate Water ◽  
Sr Isotopes ◽  
Arctic Ice ◽  
Norwegian Coastal Current

The Arctic Mediterranean Seas constitute an oceanic region in which the thermohaline circulation has a strong advective component and deep ventilation processes are very active relative to other oceanic areas. Details of the nature of these circulation and ventilation processes have been revealed through use of Cs and Sr isotopes from bomb-fallout and nuclear-waste sources as ocean tracers. In both cases, their regional input is dominated by advective supply in the Norwegian Atlantic Current and Norwegian Coastal Current, respectively. The different temporal, spatial, and compositional input patterns of these tracers have been used to study different facets of the regional circulation. These input differences and some representative applications of the use of these tracers are reviewed. The data discussed derive from samples collected both from research vessels and from Arctic ice camps. The topics addressed include: ( a ) the role of Arctic Intermediate Water as source, supplying recent surface water to North Atlantic Deep Water via the Denmark Strait overflow; ( b ) deep convective mixing in the Greenland Sea; ( c ) circulation or recirculation of Atlantic water in the Arctic basins; and ( d ) the role of Arctic shelfwaters in the ventilation of intermediate and deep water in the Eurasian and Canadian basins.

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