Climate Anomalies Induced by the Arctic and Antarctic Oscillations: Glacial Maximum and Present-Day Perspectives

2008 ◽  
Vol 21 (3) ◽  
pp. 459-475 ◽  
Author(s):  
F. Justino ◽  
W. R. Peltier
Keyword(s):  
Glacial Maximum ◽  
The Arctic ◽  
Positive Phase ◽  
Boreal Winter ◽  
Antarctic Oscillation ◽  
Climate Anomalies ◽  
The North ◽  
Surface Climate ◽  
The Antarctic ◽  
The Impact

Abstract Based on multicentury coupled climate simulations of both modern and glacial maximum conditions, this study focuses on the impact of the Arctic Oscillation (AO) and the Antarctic Oscillation (AAO) on the earth’s surface climate. Intercomparison of the results obtained in numerical experiments for both climate epochs demonstrates that highly significant changes of surface climate are predicted to have occurred depending upon the phase of the AO and AAO. These climate anomalies differ substantially between the modern and Last Glacial Maximum (LGM) states and exhibit a strong seasonal cycle under the latter conditions. Additional investigation has revealed that an intensification of the subtropical gyres in the North Atlantic and North Pacific that are induced during the positive phase of the AO plays a key role in the development of positive sea surface temperature (SST) anomalies in midlatitudes. In the Southern Hemisphere, similarly significant and systematic climate shifts are shown to occur due to variations of the Antarctic Oscillation that are highlighted by a warming over the Antarctic Peninsula and midlatitudes during the positive phase of the AAO. Finally, the authors find that the temporal variability of the AO and of the Pacific decadal oscillation (PDO) is significantly anticorrelated, with this coupling being independent of the season under present-day conditions. Under LGM conditions, however, due to the intensified vigor of the atmospheric circulation, the coupling is found to be stronger during boreal winter.

Cooling of the Northern Hemisphere triggered by Northeast Atlantic opening at the Eocene – Oligocene Transition 

2021 ◽  
Author(s):  
Eivind Straume ◽  
Aleksi Nummelin ◽  
Carmen Gaina ◽  
Kerim Nisancioglu
Keyword(s):  
Southern Ocean ◽  
Northern Hemisphere ◽  
Ocean Circulation ◽  
The Arctic ◽  
The North ◽  
Dynamic Support ◽  
Climate Transition ◽  
Iceland Plume ◽  
The Antarctic ◽  
The Impact

<p>The Eocene – Oligocene Transition (~33.7 million years ago), marks the largest step transformation within the Cenozoic cooling trend, and is characterized by a sudden growth of the Antarctic ice sheets. The role of changes in oceanic basin configuration and the evolution of key oceanic gateways in triggering these climatic variations remains disputed. Here we implement a new state-of-the-art paleogeography model in the Norwegian Earth System Model (NorESM-F) to investigate the effect of oceanic gateway changes on the Eocene – Oligocene climate. We run different cases using realistic max/min depth configurations of the Atlantic – Arctic oceanic gateways, the Tethys Seaway, and the Southern Ocean gateways, and investigate the ocean and climate sensitivity to these changes. In addition, we run separate simulations investigating the impact on the carbon cycle. The models show that changes in the Atlantic – Arctic gateways (i.e. Greenland – Scotland Ridge and the Fram Strait) cause the most significant changes in ocean circulation and climate compared to the Southern Ocean gateways or the Tehthys Seaway. The Iceland mantle plume caused depth variations on the Greenland – Scotland Ridge at this time, and our model result indicate that variations in dynamic support from the Iceland plume could have played a key role in the Eocene – Oligocene climate transition. Essentially, reduced dynamic support from the plume deepen the Greenland – Scotland Ridge and cause freshwater leakage from the Arctic Ocean which inhibits deep water formation in the North Atlantic, reducing the AMOC and ultimately cool the Northern Hemisphere.</p>

Healthcare System in the Arctic Zone of Russia. Known and Emerging Issues and Solutions to Them

2019 ◽  
pp. 3-20
Author(s):  
V.N. Leksin
Keyword(s):  
Metallurgical Industry ◽  
Healthcare Services ◽  
The Arctic ◽  
Russian Arctic ◽  
Arctic Zone ◽  
Shift Workers ◽  
The North ◽  
Medical Institutions ◽  
Emerging Issues ◽  
The Impact

The impact on healthcare organization on the territory of Russian Arctic of unique natural and climatic, demographic, ethnic, settlement and professional factors of influencing the health of population, constantly or temporarily living on this territory is studied. The necessity is substantiated of various forms and resource provision with healthcare services such real and potential patients of Arctic medical institutions, as representatives of indigenous small peoples of the North, workers of mining and metallurgical industry, military personnel, sailors and shift workers. In this connection a correction of a number of All-Russian normative acts is proposed.

Meridional Tripole Mode of Winter Precipitation over the Arctic and Continental North Africa–Eurasia

2021 ◽  
pp. 1
Author(s):  
Xiaolin Liu ◽  
Jianhua Lu ◽  
Yimin Liu ◽  
Guoxiong Wu
Keyword(s):  
Time Series ◽  
North Africa ◽  
North Atlantic ◽  
Hadley Cell ◽  
The Arctic ◽  
Positive Phase ◽  
The North ◽  
Ferrel Cell ◽  
The North Atlantic ◽  
Westerly Jets

AbstractWintertime precipitation is vital to the growth of glaciers in the northern hemisphere. We find a tripole mode of precipitation (PTM), with each pole of the mode extending zonally over the eastern hemisphere roughly between 30°W and 120°E, and the positive/negative/positive structure for its positive phase extending meridionally from the Arctic to the continental North Africa–Eurasia. The large-scale dynamics associated with the PTM is explored. The positive phase of the PTM is associated with the negative while eastward-shifted phase of the North Atlantic Oscillation (NAO) and a zonal band of positive SST anomaly in the tropics, together with a narrowed Hadley cell and weakened Ferrel cell. While being north-eastward tilted and separated from their North Africa-Eurasia counterpart in the climatological mean, the upper-tropospheric westerly jets over the east Pacific and north Atlantic become extending zonally and shifting southward and hence form a circumpolar subtropical jet as a whole by connecting with the westerly jets over the North Africa-Eurasia. The enhanced zonal winds over the north Atlantic promote more synoptic-scale transient eddies which are waveguided by the jet streams. The polar vortex weakens and cold air dips southward from the North Pole. Further diagnosis of the E-vectors suggests that transient eddies have a positive feedback on the weakening of Ferrel cell. Opposite features are associated with the negative phase of the PTM. The reconstructed time series using multiple linear regression on the NAO index and the tropical SST averaged over 20°S– 20°N, can explain 62.4% of the variance of the original the original precipitation time series.

scholarly journals Evolution in the cold

2000 ◽  
Vol 12 (3) ◽  
pp. 257-257 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Evolutionary Biology ◽  
Antarctic Fish ◽  
The Arctic ◽  
Polar Regions ◽  
Evolutionary Studies ◽  
Adaptive Radiations ◽  
The Antarctic ◽  
The Impact ◽  
Insight Into

Theodosius Dobzhansky once remarked that nothing in biology makes sense other than in the light of evolution, thereby emphasising the central role of evolutionary studies in providing the theoretical context for all of biology. It is perhaps surprising then that evolutionary biology has played such a small role to date in Antarctic science. This is particularly so when it is recognised that the polar regions provide us with an unrivalled laboratory within which to undertake evolutionary studies. The Antarctic exhibits one of the classic examples of a resistance adaptation (antifreeze peptides and glycopeptides, first described from Antarctic fish), and provides textbook examples of adaptive radiations (for example amphipod crustaceans and notothenioid fish). The land is still largely in the grip of major glaciation, and the once rich terrestrial floras and faunas of Cenozoic Gondwana are now highly depauperate and confined to relatively small patches of habitat, often extremely isolated from other such patches. Unlike the Arctic, where organisms are returning to newly deglaciated land from refugia on the continental landmasses to the south, recolonization of Antarctica has had to take place by the dispersal of propagules over vast distances. Antarctica thus offers an insight into the evolutionary responses of terrestrial floras and faunas to extreme climatic change unrivalled in the world. The sea forms a strong contrast to the land in that here the impact of climate appears to have been less severe, at least in as much as few elements of the fauna show convincing signs of having been completely eradicated.

Detecting drought conditions related to vegetation at west continental Europe based on variations from the North and Caspian Seas

2021 ◽  
Author(s):  
Bolin Xu ◽  
Qing He ◽  
Kwok Pan Chun ◽  
Julian Klaus ◽  
Rémy Schoppach ◽  
...  
Keyword(s):  
North Sea ◽  
Vegetation Index ◽  
Lower Troposphere ◽  
Principal Component ◽  
Positive Phase ◽  
Vegetation Patterns ◽  
Limited Region ◽  
The North ◽  
The North Sea ◽  
The Impact

<p>Teleconnections relate regional pressure patterns to local climate anomalies, influencing the variation of vegetation patterns. Over west continental Europe, droughts have been widely investigated with persistent low-frequency atmospheric circulation patterns (e.g. the North Atlantic Oscillation, NAO) with the centers over the Atlantic based on the 500mb height anomalies of the Northern Hemisphere. However, the effects of teleconnection patterns with the centers of active variability over the North and Caspian Seas is largely unexplored for droughts related to vegetation patterns. In this study, we explored the impact of the North Sea-Caspian Pattern (NCP) on regional ecohydrologic conditions in the Greater Region of Luxembourg in Western Europe. Using a Principal Component Analysis (PCA), we first decomposed the annual Normalized Difference Vegetation Index (NDVI) from the Global Inventory Monitoring and Modeling System (GIMMS) between 1981 and 2015. In the first PCA component, a distinctive greening trend of NDVI is detected since the late 1980s. However, the corresponding station observations and the ERA5 reanalysis data show that the region in west continental Europe became increasingly drier based on the difference between precipitation and evaporation. We explain the above paradoxical greening but drying patterns by the mechanism of NCP over the region. During the positive phase of NCP, the high pressure over the North Sea weakens circulation over the region and leads to warmer conditions in west continental Europe. These conditions are good for vegetation growth because the region was mainly energy-limited during the observed period at the annual scale based on a Budyko analysis. However, the positive phase of NCP also promotes divergent conditions at the lower troposphere and it reduces moisture flux over the region. In the Budyko space, the persistent positive phase of NCP would lead the energy-limited region to be water-limited. As the positive phase of NCP is expected to be more frequent along with the increasing global temperatures, the region may start to experience increasing water stress on vegetation. These results suggest that unforeseen droughts related to vegetation may be emerging in the region. New drought monitoring and management measures related to vegetation should be developed at west continental Europe, especially during the positive phase of NCP.</p>

scholarly journals Tropical and Midlatitude Impact on Seasonal Polar Predictability in the Community Earth System Model

2019 ◽  
Vol 32 (18) ◽  
pp. 5997-6014 ◽  
Author(s):  
Edward Blanchard-Wrigglesworth ◽  
Qinghua Ding
Keyword(s):  
Forecast Skill ◽  
Specific Humidity ◽  
The Arctic ◽  
The North ◽  
Perfect Model ◽  
Community Earth System Model ◽  
Free Running ◽  
Skill Improvement ◽  
The Tropics ◽  
The Impact

Abstract The impact on seasonal polar predictability from improved tropical and midlatitude forecasts is explored using a perfect-model experiment and applying a nudging approach in a GCM. We run three sets of 7-month long forecasts: a standard free-running forecast and two nudged forecasts in which atmospheric winds, temperature, and specific humidity (U, V, T, Q) are nudged toward one of the forecast runs from the free ensemble. The two nudged forecasts apply the nudging over different domains: the tropics (30°S–30°N) and the tropics and midlatitudes (55°S–55°N). We find that the tropics have modest impact on forecast skill in the Arctic or Antarctica both for sea ice and the atmosphere that is mainly confined to the North Pacific and Bellingshausen–Amundsen–Ross Seas, whereas the midlatitudes greatly improve Arctic winter and Antarctic year-round forecast skill. Arctic summer forecast skill from May initialization is not strongly improved in the nudged forecasts relative to the free forecast and is thus mostly a “local” problem. In the atmosphere, forecast skill improvement from midlatitude nudging tends to be largest in the polar stratospheres and decreases toward the surface.

The Polar Regions and the Development of International Law: Contemporary Reflections and Twenty-First Century Challenges

2013 ◽  
Vol 5 (1) ◽  
pp. 233-251 ◽  
Author(s):  
Donald R. Rothwell
Keyword(s):  
International Law ◽  
First Century ◽  
The Arctic ◽  
Polar Regions ◽  
Foundational Research ◽  
Twenty First Century ◽  
Legal Frameworks ◽  
Global Affairs ◽  
The Antarctic ◽  
The Impact

Abstract The polar regions are increasingly coming to the forefront of global affairs in ways that are beginning to approach the prominence given to the polar regions during the ‘heroic era’ of exploration at the beginning of the twentieth century. This contemporary focus is, however, very much upon governance and the capacity of the existing and future legal frameworks to govern the Antarctic and Arctic effectively. This article revisits foundational research undertaken in 1992–1993 and reassesses the impact of the polar regions upon the development of international law. Particular attention is given to environmental management, living and nonliving resource management, the regulation and management of maritime areas, and governance mechanisms and frameworks. The article seeks to critically assess whether the existing legal frameworks that operate in Antarctica and the Arctic are capable of dealing with their increasing globalisation, or whether there will be a need for new legal and governance regimes to be developed to address twenty-first century challenges.

scholarly journals The Coastal Observing System for Northern and Arctic Seas (COSYNA)

Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 379-410 ◽  
Author(s):  
Burkard Baschek ◽  
Friedhelm Schroeder ◽  
Holger Brix ◽  
Rolf Riethmüller ◽  
Thomas H. Badewien ◽  
...  
Keyword(s):  
Real Time ◽  
The Arctic ◽  
Arctic Seas ◽  
The Public ◽  
The North ◽  
Data Products ◽  
The North Sea ◽  
Arctic Coast ◽  
The Impact

Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change.The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

scholarly journals The INGV–CMCC Seasonal Prediction System: Improved Ocean Initial Conditions

2010 ◽  
Vol 138 (7) ◽  
pp. 2930-2952 ◽  
Author(s):  
Andrea Alessandri ◽  
Andrea Borrelli ◽  
Simona Masina ◽  
Annalisa Cherchi ◽  
Silvio Gualdi ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Seasonal Prediction ◽  
Global Scale ◽  
Tropical Pacific ◽  
Optimal Interpolation ◽  
Boreal Winter ◽  
Prediction System ◽  
Ensemble Forecasts ◽  
Climate Anomalies ◽  
The Impact

Abstract The development of the Istituto Nazionale di Geofisica e Vulcanologia (INGV)–Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC) Seasonal Prediction System (SPS) is documented. In this SPS the ocean initial-conditions estimation includes a reduced-order optimal interpolation procedure for the assimilation of temperature and salinity profiles at the global scale. Nine-member ensemble forecasts have been produced for the period 1991–2003 for two starting dates per year in order to assess the impact of the subsurface assimilation in the ocean for initialization. Comparing the results with control simulations (i.e., without assimilation of subsurface profiles during ocean initialization), it is shown that the improved ocean initialization increases the skill in the prediction of tropical Pacific sea surface temperatures of the system for boreal winter forecasts. Considering the forecast of the 1997/98 El Niño, the data assimilation in the ocean initial conditions leads to a considerable improvement in the representation of its onset and development. The results presented in this paper indicate a better prediction of global-scale surface climate anomalies for the forecasts started in November, probably because of the improvement in the tropical Pacific. For boreal winter, significant increases in the capability of the system to discriminate above-normal and below-normal temperature anomalies are shown in both the tropics and extratropics.

scholarly journals The Occurrence and Properties of Long-Lived Liquid-Bearing Clouds over the Greenland Ice Sheet and Their Relationship to the North Atlantic Oscillation

2018 ◽  
Vol 57 (4) ◽  
pp. 921-935 ◽  
Author(s):  
Jonathan Edwards-Opperman ◽  
Steven Cavallo ◽  
David Turner
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
The Arctic ◽  
Positive Phase ◽  
Cloud Base ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractStratiform liquid-bearing clouds (LBCs), defined herein as either pure liquid or mixed-phase clouds, have a large impact on the surface radiation budget across the Arctic. LBCs lasting at least 6 h are observed at Summit, Greenland, year-round with a maximum in occurrence during summer. Mean cloud-base height is below 1 km for 85% of LBC cases identified, 59% have mean liquid water path (LWP) values between 10 and 40 g m−2, and most produce sporadic light ice-phase precipitation. During their occurrence, the atmosphere above the ice sheet is anomalously warm and moist, with southerly winds observed over much of the ice sheet, including at Summit. LBCs that occur when the North Atlantic Oscillation (NAO) is in the negative phase correspond to strong ridging centered over the Greenland Ice Sheet (GIS), allowing for southwesterly flow over the GIS toward Summit. During the positive phase of the NAO, the occurrence of LBCs corresponds to a cyclone located off the southeastern coast of the ice sheet, which leads to easterly-to-southeasterly flow toward Summit. Furthermore, air parcels at Summit frequently originate from below the elevation of Summit, indicating that orographic lift along the ice sheet is a factor in the occurrence of LBCs at Summit. LBCs are more frequently observed during the negative NAO, and both the LWP and precipitation rate are larger in LBCs occurring during this phase. Mean LWP in LBCs occurring during the negative NAO is 15 g m−2 larger than in LBCs occurring during the positive phase.

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