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Tytuł:
Algae in the annual sea ice at Hooker Island, Franz Josef Land, in August 1991
Autorzy:
Okolodkov, Yuri B.
Powiązania:
https://bibliotekanauki.pl/articles/2052736.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Franz Josef Land
phycology
sea-ice algae
Źródło:
Polish Polar Research; 1993, 14, 1; 25-32
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Arctic – the new “Great Game” or peaceful cooperation
Autorzy:
Gabrielson, Risto
Śliwa, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/576259.pdf
Data publikacji:
2014-09-30
Wydawca:
Akademia Sztuki Wojennej
Tematy:
international security
the Arctic Circle
climate change
Northern Sea Route
the Arctic Council
Opis:
The Arctic area with its harsh climate and austere icecap has not raised any great international passions in the past. However, enduring global warming has opened new views on exploitation of that area. If the climate gets steadily warmer in the future, it could mean the opening of the Northwest Passage for ship routes. On the other hand, it is estimated that the region has got remarkable gas reserves, which could amount to as much as 30 % of the world’s undiscovered reserves, as well as oil, which encompasses some 13 % of world’s undiscovered stocks. As for now, any serious international conflicts in this area are not likely, even though there are real expectations and claims imposed by several nations. The current peaceful cooperation is supported by feasible treaties that are already in place. Until lately, the work of the Arctic Council has not raised any great international attentiveness, but the expected development in the area has activated stronger interest from many countries, and not only those from the Arctic region. There are several regional disputes among the five states, USA, Canada, Russia, Norway and Denmark about the Arctic Ocean. As expert opinion still differs quite significantly about the resources available in the Arctic region and about the feasibility of the Northwest and Northeast routes, it is hard to say if there are any practical economic gains to be achieved. Although cooperation between the nations has been peaceful, the military presence in the area is increasing. Moreover, it remains to be seen how the recent Ukrainian crisis will affect the development in the area.
Źródło:
Security and Defence Quarterly; 2014, 4, 3; 87-119
2300-8741
2544-994X
Pojawia się w:
Security and Defence Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Arctic shipping routes as alternative to the Suez Canal
Autorzy:
Pawelski, Jan
Powiązania:
https://bibliotekanauki.pl/articles/24202519.pdf
Data publikacji:
2022
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
arctic maritime transport
arctic shipping
Arctic Sea routes
Northern Sea Route navigation
Northwest Passage navigation
polar maritime transport
Opis:
The grounding of a 400-meter long container vessel, called Ever Given, in the Suez Canal blocked the busiest shipping lane, which is responsible for 12% of seaborne trade, for 6 days. Some shipping companies had to divert their vessels and they had to take a much longer route around Africa to reach European ports. The concerned shipping industry started to look for alternative sea route to the Suez Canal with lesser risk of blockage, without a need to go around Africa. Such routes, which connect the Pacific and Atlantic Oceans, exist in the Arctic and the warming of the global climate makes them more accessible over time but the assessment of their viability requires a multifaceted analysis based on available professional navigational publications, scientific papers, and knowledge of polar shipping realities. Several nautical aspects are taken into account with the purpose of choosing a polar route that is most suitable as an alternative to the Suez Canal. Three routes are under consideration. One of them is the Northern Sea Route in the eastern part of the Arctic Ocean, along the coast of the Russian Federation. The second route is the Northwest Passage through the western part of the Arctic, passing waters belonging to Greenland, Canada, and the United States. The third one passes near the North Pole, a prospective route that may become available for commercial shipping in the future due to Arctic ice shrinkage, and it is known as the Transpolar Route. Analysis of these routes unambiguously point to the Northern Sea Route as the only viable option. Most prospective alternatives to the Suez Canal are technically feasible with the new generation of cargo vessels and they are experiencing a growth in maritime traffic together with a steady development of associated infrastructure. The existing simplified analyses of the transit costs, assuming strait passage in polar waters without any course deviation and the additional fuel that is burnt to overcome increased friction during passage in ice, shows that under present conditions that the Suez Canal Route is still cheaper than any polar transit and, moreover, offers year-round availability. It cannot be ruled out that the upcoming warming of the Arctic climate, and a lowering of the transit tariffs by the Russian Federation may tip the balance in favor of the Northern Sea Route. Presented here is an analysis of the competitiveness of the Arctic Routes in comparison to the Suez Canal from the perspective of the mariner.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2022, 70 (142); 41--51
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania polarne Akademii Morskiej w Gdyni
Polar research Gdynia Maritime University
Autorzy:
Marsz, A. A.
Styszyńska, A.
Powiązania:
https://bibliotekanauki.pl/articles/260800.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Klimatologów Polskich
Tematy:
historia badań polarnych
bibliografia polarna
meteorologia
klimatologia
oceanologia
lody morskie
Hornsund
Spitsbergen
Arktyka
Stacja Arctowskiego
Półwysep Antarktyczny
Antarktyka
history of polar research
polar bibliography
meteorology
climatology
oceanography
sea ice
Arctic
Arctowski Station
Antarctic Peninsula
Antarctica
Opis:
W pracy omówiono tematykę badań prowadzonych przez pracowników Wyższej Szkoły Morskiej/Akademii Morskiej w Gdyni w wysokich szerokościach półkul północnej i południowej. W latach 1975-2015 pracownicy tej uczelni opublikowali łącznie 231 artykułów, komunikatów i sprawozdań oraz 14 pozycji książkowych o charakterze monograficznym dotyczących różnych aspektów badań polarnych. Wśród tych prac 142 pozycje dotyczyły Arktyki i 103 pozycje – Antarktyki. Podstawowa problematyka badawcza obejmowała zagadnienia zmienności i zmian warunków hydroklimatycznych w Arktyce i Antarktyce, kształtowania się warunków lodowych i problemów żeglugi w lodach oraz zagadnień uprawiania żeglugi w rejonach słabo rozpoznanych pod względem nawigacyjnym, w tym badań dotyczących batymetrii dna i geomorfologii wybrzeży. Artykuł zawiera jako załącznik bibliografię prac polarnych pracowników Wyższej Szkoły Morskiej i Akademii Morskiej w Gdyni.
The paper discusses topics of research conducted by the staff of the Gdynia Maritime University in the high latitudes of northern and southern hemispheres. In the years 1975-2015 the employees of the university have published a total of 231 articles, communications and reports and 14 books of monographic covering various aspects of polar research. Among the 142 works related to the Arctic positions and 103 positions – Antarctica. The basic research problems included issues variability and change hydro-climatic conditions in the Arctic and Antarctic, the formation of ice conditions and navigation in ice problems and issues of navigation in areas poorly recognized in terms of navigation, including research on the bottom bathymetry and geomorphology coasts. The article includes as an annex a bibliography of works polar employees Gdynia Maritime University.
Źródło:
Problemy Klimatologii Polarnej; 2015, 25; 75-98
1234-0715
Pojawia się w:
Problemy Klimatologii Polarnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biodiversity of the Arctic Ocean in the face of climate change
Autorzy:
Weslawski, J.M.
Powiązania:
https://bibliotekanauki.pl/articles/11979.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biodiversity
Arctic Ocean
climate change
global climate change
Arctic sea
aquatic ecosystem
Arctic environment
sea water
water temperature
salinity level
Opis:
Global climate changes which has been observed over the recent years affects organisms occurring in the Arctic seas and the functioning of the whole maritime ecosystems there. The research note presents and briefly analyses the biological diversity of the Arctic Ocean and the most important factors which change the relations between organisms and the environment in the Arctic.
Źródło:
Papers on Global Change; 2011, 18
2300-8121
1730-802X
Pojawia się w:
Papers on Global Change
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Contrasting zooplankton communities (Arctic vs. Atlantic) in the European Arctic Marginal Ice Zone
Autorzy:
Blachowiak-Samolyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/47495.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
zooplankton community
Arctic water
Fram Strait
temperature
Barents Sea
Atlantic water
salinity
environmental factor
Opis:
Relationships between the zooplankton community andv arious environmental factors (salinity, temperature, sampling depth and bottom depth) were established in the European Arctic Marginal Ice Zone (MIZ) using multivariate statistics. Three main zooplankton communities were identified: an Atlantic Shallow Community (AtSC), an Arctic Shallow Community (ArSC) anda Deep Water Community (DWC). All species belonging to AtSC andArSC were pooledandtheir relative abundances in the total zooplankton calculated with respect to a particular layer (surface, midan dd eep strata), regions (the Barents Sea, Fram Strait andt he waters off northern Svalbard), years (1999 or 2003) and seasons (spring or autumn). Mapping of the proportions of Arctic andA tlantic species ledto the conclusion that zooplankton from the MIZs do not exactly follow complementary water masses, although the general pattern of AtSC and ArSC dominance accords with the physical oceanography of the study area (AtW and ArW respectively). The mid layer proved to be a better predictor of mesozooplankton distribution than the unstable conditions near the surface.
Źródło:
Oceanologia; 2008, 50, 3; 363-389
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diversity, distribution and ecology of benthic amphipods (Amphipoda, Gammaridea) in the Barents Sea sublittoral
Autorzy:
Bryazgin, Valery
Powiązania:
https://bibliotekanauki.pl/articles/2052484.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Barents Sea
sublittoral
benthos
Amphipoda
Gammaridea
Źródło:
Polish Polar Research; 1997, 18, 2; 89-106
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functionality of Sea Ice Data Sources on the NSR
Autorzy:
Pastusiak, T.
Powiązania:
https://bibliotekanauki.pl/articles/117634.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Northern Sea Route
e-Navigation
sea ice data source
ISM Code
ice navigation
IRIDIUM Satellite System
arctic area
ice certificate
Opis:
The functionality of available official sources of sea ice data for the Northern Sea Route to date is low. In recent years a large number of new publicly available sources have appeared. Their functionality for purposes of route planning has yet to be evaluated. This study presents results of qualitative and expert analyses of various sources. It is proposed to use new indicators to enable comparison of functionality of data sources. New sources provide the technical progress that is instrumental in reducing the amount of effort and influence of the human factor in the decision-making system. The study also presents solutions to the problem of limited bandwidth available at high latitudes with Iridium satellite system. Presented solutions can be used on any vessel by any company or navigator to implement or design the decision support system related to route planning in ice in accordance with the requirements of the ISM Code and concept of e-Navigation.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2016, 10, 3; 441-450
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Greenland whales and walruses in the Svalbard food web before and after exploitation
Autorzy:
Weslawski, J.M.
Hacquebord, L.
Stempniewicz, L.
Malinga, M.
Powiązania:
https://bibliotekanauki.pl/articles/47767.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Balaena mysticetus
food web
plankton
walrus
whale
Arctic
coastal ecosystem
Svalbard Archipelago
sea mammal
Odobaenus rosmarus rosmarus
exploitation
benthic organism
Greenland whale
Opis:
Between 1600 and 1900 two numerous and ecologically important large marine mammals were extirpated in the Svalbard archipelago. These were the pelagic-feeding Greenland whale (Balaena mysticetus) and the benthic-feeding walrus (Odobaenus rosmarus rosmarus), the initial stocks of which prior to exploitation are estimated to have numbered approximately 46 000 and 25 000 animals respectively. Their annual food consumption at that time is estimated to have been some 4 million tons of plankton and 0.4 million tons of benthic organisms. Assuming that the primary and secondary production of the shelf/coastal ecosystem in the 16th century (before the peak of the Little Ice Age) was similar to that of the present day, the authors have concluded that a major shift in the food web must have occurred after the Greenland whales and walruses were eliminated. Planktonivorous seabirds and polar cod (Boreogadus saida) very probably took advantage of the extirpation of the Greenland whales, while eiders (Somateria mollissima) and bearded seals (Erignathus barbatus) benefited from the walrus's extinction. In turn, the increased amount of pelagic fish provided food for piscivorous alcids and gulls, and may have given rise to the huge present-day seabird colonies on Svalbard.
Źródło:
Oceanologia; 2000, 42, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ice conditions affecting passage of Polish vessels convoy though the NSR in 1956. Long-term ice forecasts and passage strategies
Autorzy:
Pastusiak, T.
Powiązania:
https://bibliotekanauki.pl/articles/117507.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
arctic shipping
ice conditions
Northern Sea Route (NSR)
ice forecast
history of navigation
passage startegies
Polish vessels convoy
ESIMO
Opis:
The goal of the study was to examine ice cover conditions that accompanied the passage of convoy of seven Polish vessels from Europe to the Far East in year 1956, which initiated an international commercial shipping transit. Several different sources of information on the state of ice cover in the Arctic were used in this study. Ice conditions (decisive for ability of a merchant vessel or icebreaker to cross the route) during the following navigational seasons in most of the NSR areas showed extremely divergent results - from the most favorable to the most difficult and vice versa. Existing in years 1940-1957 ice cover conditions and shipbuilding technologies did not guarantee a successful transit passage in one navigation season. The Soviet Union used icebreakers that were not able to lead vessels in heavy ice conditions that occurred in 1950s. The NSR Administration used passive strategy ? waiting for improvement of ice conditions - instead of forcing heavy ice. Passive strategy of navigation through the NSR included wintering and continuation of passage next year when ice conditions improved. Annual variability of ice conditions approximated by third degree polynomial line showed trends well. However, the high annual anomalies of ice conditions in relation to trend line did not allow for effective forecasts on particular sections of the NSR in next navigation season.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2018, 12, 1; 101-106
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kalibracja dawnych map zasięgu lodów morskich w Arktyce z zastosowaniem systemów informacji geograficznej
Georeferencing of Old Maps of Sea-ice Range in the Arctic Using GIS
Autorzy:
Lange, K.
Powiązania:
https://bibliotekanauki.pl/articles/204341.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Geograficzne
Tematy:
GIS historyczny
kalibracja
mapa
Arktyka
historical GIS
georeferencing
sea ice
Arctic
Opis:
Podstawowym materiałem badawczym do analizy zmian w czasie zasięgu lodów morskich w Arktyce są mapy archiwalne. Poprawne przeprowadzenie takich analiz umożliwiają Systemy Informacji Geograficznej (GIS). Celem pracy jest omówienie problemów kalibracji dawnych map lodowych Arktyki z I połowy XX wieku, pochodzących z Duńskiego Instytutu Meteorologicznego. Świadomość błędów, które powstają już w momencie określania pozycji statku czy szacowania odległości do obszarów pokrytych lodem rzuca światło na ogólną dokładność danych, jaka jest niezbędna przy wyborze metod rejestracji.
Archival maps of the region form the base material for the research of changes of the Arctic ice range in time. Correct and accurate analyses are possible thanks to using Geographic Information Systems (GIS). This study is about problems with georeferencing old maps of Arctic ice from the first half of the twentieth century, acquired from the Danish Meteorological Institute (DMI). Awareness of errors in determining the ship’s position or estimating the distance to ice-covered areas sheds light on the overall accuracy of the data, which is essential for the selection of a method of registration – in this case ArcGIS, version 10.0 using the georeferencing toolbar. The reason for using the affine method and problems with map registration have been discussed. The methods of registration taken into account for the purpose of this work have been divided, according to the type of layer to which the scan was knotted, into the following: – Method of point coordinates, – AOI method (linking the area of interest to the corners), – A method of linking the known content of the map (using linear or polygon shapefile). The most precise fit of the coastline has been achieved by using the method of linking the known contents of the map. The use of advanced calibration methods is not always necessary or possible due to the accuracy of the contents of the map. The information which helps recreate the process of creation of old maps and the degree of knowledge of various geographical regions at the time is of special significance. The tools used in the first half of the twentieth century made it possible to determine vessel positions with an accuracy of approximately 15 nautical miles. For calibrating the maps from DMI, the most reliable points to connect will be headlands and any kind of sharp edges of the land, giving the opportunity for clear multiple links in the process of georeferencing (calibration). Using methods based on linking multiple points is not valid if the amount of reliable link points is too small. In the early twentieth century, the only well known areas were the south coast of Greenland, Spitsbergen, Novaya Zemlya, the coast of Norway and Russia. When analyzing old maps of sea ice, we have consider numerous errors resulting from such imperfections as averaging errors, timing errors, location errors, time varying errors of measuring devices used in the first half of the 20th century, and others.
Źródło:
Polski Przegląd Kartograficzny; 2013, T. 45, nr 4, 4; 344-351
0324-8321
Pojawia się w:
Polski Przegląd Kartograficzny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Live autochthonous benthic diatoms on the lower depths of Arctic continental shelf. Preliminary results
Autorzy:
Druzhkova, E.
Oleinik, A.
Makarevich, P.
Powiązania:
https://bibliotekanauki.pl/articles/48499.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
diatom
microphytobenthos
sediment layer
Barents Sea
microalga
Gyrosigma fasciola
Pleurosigma angulatum
water column
continental shelf
Arctic
Opis:
An autochthonous community of benthic diatoms was discovered in June 2015 in the upper sediment layer at depths of 170, 205, and 245 m in the central Barents Sea. At least three benthic microalgae species (Gyrosigma fasciola, Pleurosigma angulatum, and Pleurosigma sp. 1) were detected in the sediment but not the upper water column. Analyses revealed that these benthic microalgae represent a depleted fragment of Arctic littoral microphytobenthos. Compared with the littoral flora, the deep-water assemblage is less diverse and displays low abundance. The data reported here challenge the generally accepted belief that the presence of certain microalgae at significant depths results from vertical or horizontal transfer.
Źródło:
Oceanologia; 2018, 60, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Maritime Situation Monitoring for Safe Navigation on Northern Sea Route
Autorzy:
Popovich, V.V.
Smirnova, O.V.
Popovich, T.V.
Powiązania:
https://bibliotekanauki.pl/articles/116586.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Northern Sea Route
maritime situation monitoring
safe navigation
safety at sea
Arctic shelf
Arctic area
polar navigation
geographic information system (GIS)
Opis:
Considering growing intensity of navigation on Northern Sea Route and of continuous exploration and development of Arctic shelf, problems of maritime situation monitoring in Arctic become particularly important. Firstly, complex operational informational support of activities in Arctic is needed. Secondly, constant access to actual and valid information about hydro-meteorological, navigational and ice situations is required. Solution of stated problems entails integration, processing and analysis of large amounts of heterogeneous data. Consequently, development of unified system for situation monitoring and intellectual support is essential. Such system allows to execute operational monitoring of dangerous situations of different sort (natural or anthropogenic) that influence safety of objects in Arctic region, and to perform intellectual analysis of such situations and prompt provision of suitable recommendations.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2016, 10, 3; 433-440
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Meteorological conditions on Kaffiøyra (NW Spitsbergen) in 2013–2017 and their connection with atmospheric circulation and sea ice extent
Autorzy:
Kejna, Marek
Sobota, Ireneusz
Powiązania:
https://bibliotekanauki.pl/articles/2041853.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Svalbard
climate change
weather conditions
synoptic situations
sea ice cover
Źródło:
Polish Polar Research; 2019, 40, 3; 175-204
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model zmian powierzchni lodów morskich Arktyki (1979-2013) – zmienne sterujące w modelu „minimalistycznym” i ich wymowa klimatyczna
Model of changes in the Arctic sea-ice extent (1979-2013) – variables steering the 'minimalist' model and their climatic significance
Autorzy:
Marsz, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/260796.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Klimatologów Polskich
Tematy:
Arktyka
lody morskie
zmiany powierzchni lodów
czynniki sterujące
model
cyrkulacja termohalinowa
cyrkulacja atmosferyczna
Arctic
sea ice
ice extent changes
steering variables
thermohaline circulation
atmospheric circulation
Opis:
Praca omawia model zmian powierzchni zlodzonej Arktyki typu „białej skrzynki”, opierający się na dwu zmiennych niezależnych – wskaźniku oznaczonym jako DG3L, który charakteryzuje intensywność cyrkulacji termohalinowej (THC) na Atlantyku Północnym i wskaźniku D, który charakteryzuje cyrkulację atmosferyczną nad Arktyką. Objaśnienie konstrukcji obu wskaźników i wartości ich szeregów czasowych przedstawione jest w załącznikach Z1 i Z2. Okres opracowania obejmuje lata 1979-2013 i jest limitowany dostępnością danych o zmianach powierzchni lodów morskich w Arktyce. Model liniowy opierający się na tych zmiennych objaśnia ~72% wariancji rocznej powierzchni zlodzonej w Arktyce i powyżej 65% wariancji powierzchni zlodzonej w marcu (maksimum rozwoju powierzchni lodów) i wrześniu (minimum). Główną rolę w kształtowaniu tej zmienności odgrywa zmienność cyrkulacji termohalinowej, rola cyrkulacji atmosferycznej jest niewielka i wykazuje silną zmienność sezonową. Analiza tego modelu wykazała, że rzeczywiste zależności są nieliniowe, a zmiany pokrywy lodowej zachodzą w dwu odrębnych reżimach – „ciepłym” i „chłodnym”. Reżim „ciepły” funkcjonuje w sytuacji, gdy THC jest bardziej intensywna niż przeciętnie (wskaźnik DG3L > 0). Dochodzi wtedy do szybkiego spadku powierzchni lodów w okresie ciepłym – zwłaszcza we wrześniu i powolnego spadku rozmiarów pokrywy lodowej w marcu, cyrkulacja atmosferyczna w tym reżimie odgrywa istotną rolę w kształtowaniu zmian powierzchni lodów. Spadek natężenia THC poniżej przeciętnej (DG3L ≤ 0), z opóźnieniem około 6.letnim prowadzi, do przejścia do reżimu „chodnego”. W reżimie chłodnym następuje szybki przyrost powierzchni lodów w okresie ciepłym i bardzo powolny wzrost powierzchni lodów w marcu, rola cyrkulacji atmosferycznej w kształtowaniu zmienności pokrywy lodowej staje się nikła. Po dalszych kilku latach utrzymywania się reżimu „chłodnego” międzyroczne zmiany powierzchni zlodzonej stają się małe. Analizy związków między zmiennymi z przesunięciami czasowymi wykazały, że cyrkulacja atmosferyczna nad Arktyką stanowi funkcję THC. W rezultacie, za główną przyczynę zmian powierzchni zlodzonej Arktyki należy uznać rozciągnięte w czasie działanie zmian intensywności THC, które w rozpatrywanym okresie objaśnia ~90% wariancji rocznej powierzchni zlodzonej.
The paper presents the assumptions and structure of statistical model reproducing the changes in sea ice extent in the Arctic, using the minimum number of steering variables. The data set of NASA's Goddard Space Flight Center (GSFC) nsidc0192_seaice_trends_climo/total-area-ice-extent/nasateam/ (Total Ice-Covered Area and Extent) was used as starting data in the calibration of this model. Its subsets characterizing the sea ice extent of the Arctic Ocean (ArctOcn), Greenland Sea (Grnland), Barents and Kara seas (BarKara) were used. Their sums create a new variable known as the ‘Proper Arctic’. This model also used the following subsets: Archipelago Canadian (CanArch), Bay and Strait Hudson (Hudson), and Baffin Bay and Labrador Sea (Baffin), the sum of which creates another variable the ‘American Arctic’. The sum of all the above mentioned subsets creates a variable defined as the ‘entire Arctic’. The study covered the period 1979-2013, for which the said data set is made up of uniform and reliable data based on satellite observations. The model was developed for moments of maximum (March) and minimum (September) development of sea ice extent as well as for the annual average sea ice extent. After presenting the assumptions of the model (model type ‘White box’), formal analysis of the type and characteristics of the model, the choice of steering variables (independent; Chapters 3 and 4) was made. The index characterizing the intensity of thermohaline circulation (THC) in the North Atlantic, referred to as DG3L and an index characterizing atmospheric circulation having significant influence on changes in sea ice extent, marked as D, were used as independent variables in this model. Physical fundamentals and rules for calculating the DG3L index are discussed in detail in Annex 1, and the D index in Annex 2. These Annexes also include time series of both indexes (DG3L – 1880-2015; D – 1949-2015). Research into delays between the impact of variables and changes in sea ice extent indicated that sea ice extent showed maximum strength of the correlation with the DG3L variable with a three-year delay and with D variable with zero delay. The final form of the model is a simple equation of multiple regression (equation [1]). The following equations are used for estimating the regression parameters for individual sea areas in those time series: the Proper Arctic – equation [1a, 1b, 1c]; the American Arctic – equations [2a, 2b, 2c] and for the entire Arctic - equation [3a, 3b, 3c]. Statistical characteristics of each model are presented in Tables 3, 4 and 5, and Figures 2, 3 and 4 respectively and show the scattering of values estimated by means of each model in relation to the observed values. All models show high statistical significance. The best results, both in terms of explanation of the variance of the observed sea ice extent, as well as the size of the standard errors of estimation of sea ice extent are obtained for changes in the sea ice extent of the entire Arctic. The reasons for this may be traced back to the fact that errors in the estimation of partial models ([1a, 1b, 1c] and [2a, 2b, 2c]) have different signs, which in a synthetic model partially cancel out each other. Moreover, if the variable DG3L three years before shows strong and evenly distributed in time action, the D variable characterizing atmospheric circulation shows clearly seasonal activity – it is marked only during the minimum development of sea ice extent (September), when the degree of ice concentration is reduced, allowing its relatively free drift. The model for the annual average of sea ice extent of the entire Arctic (in the accepted limits) explains 71.5% of the variance, in September 68%, and in March 65% of the variance (Table 5). The lowest values are obtained for the American Arctic, where the D variable, characterizing atmospheric circulation does not appear to have significant influence, so the model is a linear equation with one variable (DG3L). Nevertheless, also in this case, the variance of the annual sea ice extent in the American Arctic is explained exceeding 50%. Variability of THC (described by the DG3L index) explains ~67% of the variance of annual sea ice extent and variability of atmospheric circulation (described by the D index) explains ~6% of the variance of annual sea ice extent of the entire Arctic. It allows claiming that THC and atmospheric circulation are the essential factors that influence the variability of sea ice extent of the Arctic. Both of these factors are natural factors. Further analysis of the results presented by various models and especially those affected by the DG3L variable (Fig. 5) delayed by three years suggests that the linear model is not the most appropriate model reflecting the changes in the sea ice extent of the entire Arctic and its parts. The action of DG3L variable, accumulated over several years, is saved and this causes that a strong significant correlation with the sea ice extent is prolonged. The analysis carried out by means of the segmented regression showed that the variability of sea ice extent was different where THC is lower than the average (DG3L ≤ 0), or different where THC is stronger than average (DG3L> 0; see equation [4a, 4b]). When the index is zero or less than zero, the impact of THC on the increase in sea ice extent is limited and the influence of changes in atmospheric circulation on sea ice extent is very small. Conversely, when the THC becomes intense and imports increased amounts of heat to the Arctic, the influence of DG3L index on the decrease in sea ice extent rises, like growing impact of atmospheric circulation on variation of sea ice extent (see equations [5a, 5b]. The segmented regression equations with these two variables explain 88.76% of the observed annual variation of sea ice extent of the entire Arctic (equations [5a, 5b]).This means that the sea ice extent of the Arctic is variable in two distinct regimes – ‘warm’, when the DG3L> 0 and ‘cold’, when the DG3L ≤ 0. This is similar to the results of Proshutinsky and Johnson (1997), Polyakov et al. (1999) and Polyakov and Johnson (2000) and their LFO oscillation. Time limits of the transition intensity of the THC phases from the positive to negative and vice versa correspond to similar limits of LFO, suggesting that the two different systems have the same cause. Polyakov and Johnson (2000) and Polyakov et al. (2002, 2003, 2004, 2005) can see the main reason for the change in the LFO regime in the transition of atmospheric circulation from anticyclonic regime to cyclonic regime and vice versa. The analysis of the reason for the transition of regime of changes in sea ice extent from ‘warm’ to ‘cold’ and vice versa – THC or atmospheric circulation – has shown that the D index is a function of previous changes in DG3L index. Atmospheric circulation over the Arctic shows a greater delay in response to changes in THC than the sea ice extent – this occurs with a 6-year delay (see Table 6, Equation 6). This allows replacing the D variable in the equations describing the change in sea ice extent, directly by DG3L variable from 6 years before (see Equation [7a, 7b]).These simultaneous equations explain about 90% of the observed annual variance of the sea ice extent of the entire Arctic in the years 1979-2013. Most importantly, however, it can be stated, with a high degree of certainty, that the variability of THC of the North Atlantic steers both the changes in sea ice extent and Basic features of atmospheric circulation over the Arctic. The effects of other factors than THC, having influence on variability of sea ice extent and the basic processes of the climate in the Arctic, in the short time scales, leave not too much space/place. The transition from ‘cold’ to ‘warm’ regime in the development of the sea ice extent in the Arctic requires an increase in the intensity of THC. If the values of DG3L index are greater than 0 for a period not shorter than three years, the decrease in the sea ice extent will start, initially in the period of its minimum development (August, September). If the resultant values of the DG3L index have positive values for further three years, the atmospheric circulation will transform into a cyclonic circulation (D index goes to positive values). The role of atmospheric circulation during the ‘warm’ season in the Arctic having influence on the change (reduction) of the sea ice extent becomes significant. The ‘warm’ regime will remain as long as long after its start the situation in which the algebraic sum of DG3L values is greater than 0. If such a situation lasts long, or in case of accumulation of high values of DG3L index, the sea ice cover can disappear almost completely in the warm period. The transition from the ‘warm’ regime to the ‘cold’ regime demands fulfillment of reverse conditions – a consistent decrease in the values of DG3L index into negative values for at least another three year period. After three years this will result in rapid increase in sea ice extent during warm period, thereby increasing the annual average of sea ice extent. If in subsequent years the value of DG3L index remains lower than zero, after the next 3-4 years, the atmospheric circulation will become the anticyclonic circulation. After that there will be gradual, slow growth in sea ice extent, decrease in air temperature, increase in ice thickness and change in the age of the ice structure towards the increase in the multi-year ice. The ice cover in the Arctic will become "self-sustaining", reducing interannual variability. Major changes will occur in the ‘warm’ season, minor in other seasons. The maximum sea ice extent of the Arctic in the cold season, with current conditions in the ‘cold’ regime, can reach ~13.5-14.5 million km2, the average annual sea ice extent should be ~12 (± 0.5) million km2. This area, especially in the winter season, may be in fact higher, since the weakening of the THC must also lead to a decrease in air temperature in the hemisphere.
Źródło:
Problemy Klimatologii Polarnej; 2015, 25; s. 249-334
1234-0715
Pojawia się w:
Problemy Klimatologii Polarnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 47

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