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1

Water wave scattering by an infinite step in the presence of an ice-cover

Ray S., De S., Mandal B. N.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 4

157--168

EN

The classical problem of water wave scattering by an infinite step in deep water with a free surface is extended here with an ice-cover modelled as a thin uniform elastic plate. The step exists between regions of finie and infinite depths and waves are incident either from the infinite or from the finite depth water region. Each problem is reduced to an integral equation involving the horizontal component of velocity across the cut above the step. The integral equation is solved numerically using the Galerkin approximation in terms of simple polynomial multiplied by an appropriate weight function whose form is dictated by the behaviour of the fluid velocity near the edge of the step. The reflection and transmission coefficients are obtained approximately and their numerical estimates are seen to satisfy the energy identity. These are also depicted graphically against thenon-dimensional frequency parameter for various ice-cover parameters in a number of figures. In the absencje of ice-cover, the results for the free surface are recovered.

2

Analiza struktury i czasu trwania zjawisk lodowych na Warcie na tle warunków termicznych w okresie 1991-2010

Graf R., Łukaszewicz J., Jawgiel K.

Woda-Środowisko-Obszary Wiejskie

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2018

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T. 18, z. 4

5--28

PL

W artykule przedstawiono wyniki analizy struktury i czasu trwania zjawisk lodowych na Warcie w latach 1991–2010. Przebieg zjawisk lodowych został opisany na tle zmian temperatury powietrza i wody oraz wskaźnika Oscylacji Północnoatlantyckiej (NAO). Określono formy zjawisk lodowych występujących na Warcie w poszczególnych cyklach jej zlodzenia. Zinterpretowano również zmienność temperatury wody w okresie zimowym i jej wpływ na liczbę dni ze zjawiskami lodowymi. W analizie zjawisk lodowych uwzględniono: charakter odcinka rzeki, na którym prowadzono obserwacje oraz stopień antropopresji, wyrażający się przekształceniem koryta rzecznego, wpływem urbanizacji w strefach większych ośrodków miejskich oraz oddziaływaniem zbiornika Jeziorsko. Na podstawie przeprowadzonych badań wyznaczono ogólną tendencję w zmienności zjawisk lodowych występujących na rzece, a także określono przyczyny zróżnicowania struktury zjawisk w ujęciu regionalnym. Stwierdzono związek pomiędzy przebiegiem i częstością zjawisk lodowych a warunkami termicznymi i fazami NAO.

EN

The article presents the results of the analysis of the structure and duration of ice phenomena on the Warta River. The course of ice phenomena has been described against the background of air and water temperature, and North Atlantic oscillation (NAO) changes including. The forms of ice phenomena, exist on the Warta River in particular cycles of its icing, were determined. The variability of the water temperature in winter and its impact on the number of days with ice phenomena on the river has been taken into consideration. The analysis of ice phenomena has taken into account the nature of the section of the river on which observations were made, the scale of anthropopressure affecting the transformation of the riverbed, the impact of urbanization in the zones of larger urban centers and the influence of the Jeziorsko Reservoir. On the basis of the conducted research, a general tendency was determined for the variability of ice phenomena occurring on the river. Reasons for the differentiation of the structure of ice phenomena on a regional basis were determined. The results show in detail the connection between the course and frequency of ice phenomena and other hand thermal conditions and NAO phases.

3

Przyczyny i mechanizmy zmian klimatu w plejstocenie : state of art

Hrynowiecka A.

Przegląd Geologiczny

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2016

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Vol. 64, nr 1

26--34

EN

The reason of cyclic climate change during the Pleistocene is probably so-called Milankovitch cycles, consisting of three main orbital parameters of the Earth: the shape of Earth’s orbit eccentricity, axial tilt of Earth and precession – change in the direction of the Earth’s axis. They also impact on the insolation, which significantly contributes to the formation of ice sheets. The climate is conditioned largely by energy derived from the sun, dependent on the current solar activity. Specific configurations of these factors have contributed to the formation of glacial-interglacial cycles in the past; they have today and will have an impact on the climate of our planet in the future.

4

Zmiany zlodzenia Morza Karskiego w latach 1979-2015. Podejście systemowe

Styszyńska A., Marsz A. A.

Problemy Klimatologii Polarnej

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2016

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Nr 26

109--156

PL

Praca omawia zmiany powierzchni lodów na Morzu Karskim i mechanizmy tych zmian. Scharakteryzowano przebieg zmian zlodzenia, ustalając momenty skokowego zmniejszenia się letniej powierzchni lodów. Rozpatrzono wpływ cyrkulacji atmosferycznej, zmian temperatury powietrza i zmian zasobów ciepła w wodach na zmiany zlodzonej tego morza. Analizy wykazały, że wszystkie zmienne opisujące zarówno stan zlodzenia jak i stan elementów klimatycznych są ze sobą wzajemnie powiązane przez różnego rodzaju sprzężenia zwrotne. W rezultacie tworzy się rekurentny system, w którym zmiany powierzchni lodów, wpływając na przebieg innych elementów systemu (temperaturę powietrza, temperaturę wody powierzchniowej) w znacznej części same sterują swoim rozwojem. Zmiennością całego tego systemu sterują zmiany intensywności cyrkulacji termohalinowej (THC) na Atlantyku Północnym, dostarczając do niego zmienne ilości energii (ciepła). Reakcja systemu zlodzenia Morza Karskiego na zmiany natężenia THC następuje z 6.letnim opóźnieniem.

EN

The work discusses the changes in the ice extent on the Kara Sea in the years 1979-2015, i.e. in the period for which there are reliable satellite data. The analysis is based on the average monthly ice extent taken from the database AANII (RF, St. Peterburg). 95% of the variance of average annual ice extent explains the variability of the average of ice extent in ‘warm' season (July-October). Examination of features of auto-regressive course of changes in ice extent shows that the extent of the melting ice area between June and July (marked in the text RZ07-06) can reliably predict the ice extent on the Kara Sea in August, September, October and November as well as the average ice extent in a given year. Thus the changes in ice extent can be treated as a result of changes occurring within the system. Analysis of the relationship of changes in ice extent and variable RZ07-06 with the features of atmospheric circulation showed that only changes in atmospheric circulation in the Fram Strait (Dipole Fram Strait; variable DCF03-08) have a statistically significant impact on changes in ice extent on the Kara Sea and variable RZ07-06. The analysis shows no significant correlation with changes in ice extent or AO (Arctic Oscillation), or NAO (North Atlantic Oscillation). Variable RZ07-06 and variable DCF03-08 are strongly correlated and their changes follow the same pattern. Analysis of the relationship of changes in ice extent and variable RZ07-06 with changes in air temperature (the SAT) showed the presence of strong relationships. These correlations differ significantly depending on the region; they are much stronger with changes in air temperature in the north than in the south of the Kara Sea. Temperature of cold period (average temperature from November to April over the Kara Sea, marked 6ST11-04) has a significant effect on the thickness of the winter ice and in this way the thickness of ice in the next melting season becomes part of the "memory" (retention) of past temperature conditions. The thickness of the winter ice has an impact on the value of the variable RZ07-06 and on changes in ice extent during the next ‘warm’ season. As a result, 6ST11-04 explains 62% of the observed variance of the annual ice extent on the Kara Sea. SAT variability in the warm period over the Kara Sea (the average of the period July-October, marked 6ST07-10) explains 73% of the variance of annual ice extent. SAT variability of the N part of the Kara Sea (Ostrov Vize, Ostrov Golomjannyj), which explains 72-73% of the variance ice extent during this period, has particularly strong impact on changes in ice extent during warm period. These stations are located in the area where the transformed Atlantic Waters import heat to the Kara Sea. Analysis of the impact of changes in sea surface temperature (SST) variability on sea ice extent indicated that changes in SST are the strongest factor that has influence on ice extent. The variability of annual SST explains 82% of the variance of annual ice extent and 58% of the variance of the variable RZ07-06. Further analysis showed that the SAT period of warm and annual SAT on the Kara Sea are functions of the annual SST (water warmer than the air) but also ice extent. On the other hand, it turns out that the SST is in part a function of ice extent. All variables describing the ice extent and its changes as well as variables describing the nature of the elements of hydro-climatic conditions affecting the changes in ice extent (atmospheric circulation, SAT, SST) are strongly and highly significantly related (Table 9) and change in the same pattern. In this way, the existence of recursion system is detected where the changes in ice extent eventually have influence on ‘each other’ with some time shift. The occurrence of recursion in the system results in very strong autocorrelation in the course of inter-annual changes in ice extent. Despite the presence of recursion, factors most influencing change in ice extent, i.e. the variability in SST (83% of variance explanations) and variability in SAT were found by means of multiple regression analysis and analysis of variance. Their combined impact explains 89% of the variance of the annual ice extent on the Kara Sea and 85% of the variance of ice extent in the warm period. The same rhythm of changes suggests that the system is controlled by an external factor coming from outside the system. The analyses have shown that this factor is the variability in the intensity of the thermohaline circulation (referred to as THC) on the North Atlantic, characterized by a variable marked by DG3L acronym. Correlation between the THC signal and the ice extent and hydro-climatic variables are stretched over long periods of time (Table 10). The system responds to changes in the intensity of THC with a six-year delay, the source comes from the tropical North Atlantic. Variable amounts of heat (energy) supplied to the Arctic by ocean circulation change heat resources in the waters and in SST. This factor changes the ice extent and sizes of heat flux from the ocean to the atmosphere and the nature of the atmospheric circulation, as well as the value of the RZ07-06 variable, which determines the rate of ice melting during the ‘warm’ season. A six-year delay in response of the Kara Sea ice extent to the THC signal, compared to the known values of DG3L index to the year 2016, allows the approximate estimates of changes in ice extent of this sea by the year 2023. In the years 2017 to 2020 a further rapid decrease in ice extent will be observed during the ‘warm' period (July-October), in this period in the years 2020-2023 ice free conditions on the Kara Sea will prevail. Ice free navigation will continue from the last decade of June to the last decade of October in the years 2020-2023. Since the THC variability includes the longterm, 70-year component of periodicity, it allows to assume that by the year 2030 the conditions of navigation in the Kara Sea will be good, although winter ice cover will reappear.

5

Unravelling the complex nature of the Upper Weichselian till section at Gdynia Babie Doły, northern Poland

Woźniak P. P., Czubla P.

Geologos

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2016

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Vol. 22, No. 1

15--32

EN

The complexity of glacial sequences may increase when these formed underneath ice sheets despite subsequent changes in their extent that are accompanied by alterations in the direction of the ice flow. Our aim was to determine whether or not changes in ice sheet dynamics during the Late Weichselian are also recorded in sediments formed north of the area of its fluctuating margin (i.e., where the ice sheet prevailed independent of such fluctuations). It is shown that in these areas such a record could have occurred, as documented by results of till studies at Babie Doły. The examination was carried out using several analyses: lithofacies properties of sediments, petrographic till composition (fine gravel fraction, indicator erratics), till matrix CaCO3 content, till fabric, as well as orientation of striae on the top surfaces of large clasts. In parallel, datings of sub- and supra-till sediments using the TL method were carried out. The basal till at Babie Doły represents almost the entire Upper Weichselian, but it can be divided into subunits whose features indicate different ice flow directions and debris supply. The lower subunit developed as a result of the palaeo-ice stream along the main axis of the Baltic Sea (from the north), expanding to areas adjacent to the depression of the Gulf of Gdańsk. The upper subunit developed when the influence of the palaeo-ice stream in the study area decreased, the main role having been taken over by the ice flowing from the northwest. The till analysed also shows considerable lateral variation, indicative of the mosaic nature of subglacial sedimentation. We consider the diversity of permeability of deposits over which the ice sheet extended to be the prime factor that determined such a situation.

6

Zmienność pokrywy lodów morskich w okresie maksimum ich rozwoju na Morzu Grenlandzkim w i połowie XX wieku

Adrychowska K.

Problemy Klimatologii Polarnej

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2015

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Nr 25

239--248

PL

Artykuł przedstawia zmiany powierzchni lodów występujące w okresie maksimum ich rozwoju (w kwietniu) w rejonie między Grenlandią, Islandią i Spitsbergenem w latach: 1901-1939 oraz 1946-1956 oparte na analizach map lodowych udostępnionych przez Duński Instytut Meteorologiczny. Obliczeń powierzchni lodów dokonano w programie ArcGis10.0 w układzie współrzędnych North Pole Lambert Azimuthal Equal Area. Przeprowadzone pomiary powierzchni zlodzonej wskazują na dużą zmienność powierzchni lodów na obszarze między Spitsbergenem, Grenlandią i Islandią. W tym rejonie największe powierzchnie lodów wystąpiły w 1905, 1906 i 1911 roku, a najmniejsze w latach 1925 i 1930. Znacznie mniejsze zmiany powierzchni lodów miały miejsce w rejonie Cieśniny Duńskiej i na wodach między Islandią i SE Grenlandią. W tym rejonie największy rozwój pokrywy lodowej miał miejsce w 1934, 1935 oraz 1952 roku, a najmniejszy w latach 1939, 1929 i 1903. Na całym badanym obszarze największy rozwój lodów miał miejsce w okresie 1905-1918 z maksimum w latach 1906 (1638 tys. km2), 1911 i 1918. Minimum rozwoju pokrywy lodowej wystąpiło w 1933 roku (1037 tys. km2). W okresie 1901-1939 zaznacza się istotny trend malejący powierzchni lodów. Zmiany powierzchni lodów w latach 1946-1956 charakteryzują się dużą stabilnością oscylującą między 1300 a 1500 tys. km2.

EN

The article present changes of sea ice extent during a period of time when they developed most (April) in the geographical area located between Greenland, Iceland and Spitsbergen during years 1901-1939 and 1945-1956 based on data shared by Danish Meteorological Institute. Surface calculations were made by using ArcGis 10.0 software, using geographical coordinate system North Pole Lambert Azimuthal Equal Area. Results of the calculations show high deviations of sea ice extent at investigated area. Biggest surface area noted in 1905, 1906 and 1911 and smallest in 1925 and 1930. Much smaller changes were observed and at the sea between Iceland and South-Eastern Greenland. During the period 1901-1939 a diminishing trend was observed there considering ice surface area. Years 1946-1956 remain with a stable amount of ice surface.

7

Effect of the North Atlantic Oscillation on the Pattern of Lake Ice Phenology in Poland

Wrzesiński D., Choiński A., Ptak M., Skowron R.

Acta Geophysica

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2015

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Vol. 63, no. 6

1664--1684

EN

This paper presents an analysis of the influence of the North Atlantic Oscillation on the pattern of lake ice phenology in Poland. The research embraced 22 lakes in Poland over the period 1961-2010. Strong relations were found to hold between NAO and individual characteristics of ice phenology. In a negative NAO phase, one can observe a later appearance of ice phenomena and ice cover compared with the average values, ice cover persisting even 30 days longer and being thicker even by more than 10 cm. In turn, in a positive NAO phase the duration of ice phenomena and ice cover is shorter, the cover being less thick and solid. The observed spatial differences in the effect of NAO on the pattern of ice phenomena in Poland show this matter to be fairly complex. The most significant factor changes in climatic conditions, which manifest themselves in the continentality of the climate growing eastwards.

8

Zjawiska lodowe na głównych rzekach Regionu Wodnego Środkowej Wisły w sezonie zimowym 2013/2014

Trubalski A.

Gospodarka Wodna

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2014

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Nr 6

215--217

PL

Na początku sezonu zimowego 2013/2014 stany wód w Regionie Wodnym Środkowej Wisły układały się głównie w strefie stanów niskich i średnich oraz lokalnie wysokich. W grudniu i w pierwszej dekadzie stycznia 2014 r. główne rzeki regionu pozostawały wolne od zjawisk lodowych ze względu na występowanie dodatniej średniej dobowej temperatury powietrza. W drugiej dekadzie stycznia, w wyniku gwałtownego spadku temperatury powietrza od 21 stycznia, na głównych rzekach Regionu Wodnego Środkowej Wisły zaczęły powstawać zjawiska lodowe.

9

Zmiany powierzchni lodów morskich w rejonie Svalbardu w latach 1901-1930

Lange K.

Problemy Klimatologii Polarnej

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2013

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Nr 23

169--179

PL

Niedawno udostępnione mapy Duńskiego Instytutu Meteorologicznego (DMI) rzucają nowe światło na zmiany zasięgu lodów w Arktyce Atlantyckiej, które dotychczas były głównie oparte na zbiorach archiwalnych Norweskiego Instytutu Meteorologicznego. Artykuł przedstawia zmiany letniej pokrywy lodowej na obszarze między 50°W, a 70°E w sierpniach lat 1901-1930 obliczone na podstawie zmian zasięgu lodów w tym rejonie pokazanych na mapach z archiwum DMI. Obliczenia powierzchni lodów zostały dokonane w programie ArcGis 10.0 w układzie współrzędnych North Pole Lambert Azimuthal Equal Area. Przeprowadzone pomiary powierzchni zlodzonej potwierdzają rozrost pokrywy lodowej w latach 1907-1918 z maksimum w latach 1912 i 1913 oraz występowanie drugorzędnego maksimum rozwoju lodów w latach 1916 i 1917, po którym nastąpił ogólny spadek powierzchni lodów. W tym czasie wykrywa się dwie fazy gwałtownego spadku pokrywy lodowej na badanym akwenie – między rokiem 1921 i 1922 oraz między rokiem 1929 i 1930. Taki przebieg zmian powierzchni lodów w momencie bliskim osiągnięcia przez nie minimum rozwoju w cyklu rocznym jest z dużym przybliżeniem zgodny ze znanymi z pomiarów zmianami temperatury powietrza w tej części Arktyki.

EN

Latest maps released by the Danish Meteorological Institute (DMI ) shed new light on the changes in the Arctic ice coverage that have been mainly based on archival Norwegian Meteorological Institute. The article presents the changes in the surface of sea ice in the area between 50°W and 70°W for the years 1901 to 1930 August , calculated on the basis of changes in ice coverage in the area shown on maps from the archives of DMI . ice surface Calculations have been made in the coordinate North Pole Lambert Azimuthal Equal Area using ArcGis 10.0 The measurements confirm iced surface of ice cover growth in the years 1907-1918 with a maximum between 1912 and 1913 and the presence of a secondary maximum ice growth in the years 1916 and 1917, after which there was a general decline in sea ice area. During this time, detected two phases of rapid decline of ice cover in the examined area between 1921 and 1922 and between 1929 and 1930. Such a course of changes in sea ice area at a time moment close to minimum of the annual cycle of development is close approximation consistent with known from measurements of air temperature changes in this part of the Arctic.

10

Wpływ zjawisk lodowych na erozję brzegów koryta rzecznego na przykładzie rzeki Łyny

Kalinowski A., Glińska-Lewczuk K, Burandt P, Banaszek Ż

Inżynieria Ekologiczna

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2012

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Nr 31

57--71

PL

W artykule podjęto próbę analizy wpływu zjawisk lodowych na erozję brzegów koryta rzeki pojeziernej na przykładzie rzeki Łyny (północno-wschodnia Polska). Do analizy wytypowano przekrój Smolajny, położony w jej środkowym biegu. Badania przeprowadzono w latach hydrologicznych 2005-2012. W badanym okresie obserwowano występowanie, rozwój i intensywność zjawisk lodowych, takich jak: lód brzegowy, pokrywa lodowa, spływ wody na lodzie na tle zmian cech morfologicznych koryta rzecznego. W wyniku obserwacji stwierdzono skokowe zwiększenie się szerokości koryta w badanym profilu poprzecznym (dwukrotnie po 0,5 m). Związane było to z długim czasem zalegania grubej pokrywy lodowej. W latach 2005-2012 zaobserwowano fluktuacje wielkości cech morfometrycznych, zarówno dodatnie jak i ujemne. Czynnikiem kształtującym brzegi koryta są ponadto gwałtowne roztopy pokrywy śnieżnej przy jednoczesnym utrzymywaniu się pokrywy lodowej. Wpływa to na zwiększone podmywanie brzegów koryta. Wykazano, że w badanym okresie nastąpiło zwiększenie szerokości koryta w badanym przekroju o jeden metr, zwiększenie powierzchni przekroju poprzecznego oraz głębokości maksymalnej i średniej.

EN

The aim of the paper is attempt to analysis influence on bank erosion on example Łyna river (NE Poland). The analysis has been performed at the cross section of Smolajny during hydrological years 2005-2012. In that period we observed occurrence, evolution and intensity of ice phenomena, such as: border ice, ice cover, water runoff on ice cover. Simultaneously, hydrological and morphological measurements of bed channel have been done. Results showed that width of river bed had increase, bit by bit (twice by 0,5 m), in observed cross section. There was observed fluctuation attributes of morphology in years 2005-2012, both positive and negative. Sudden snowmelt has a great impact on bank erosion, with prolonged ice cover. That situation has influence on sapping of banks. It was stated that, in spite of fluctuations of channel morphological parameters, the overall increase in the channel width was at about 1m in 2005-2012. Similarly other parameters, as wetted area, maximal and average depths have increased in those years.

11

Możliwości torowania drogi statkom, podczas akcji kruszenia pokrywy lodowej, z użyciem holownika z napędem azymutalnym

Herdzik J.

Logistyka

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2011

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nr 5

PL

W przypadku zalodzenia redy, awanportu i kanałów portowych powstaje problem wejścia statku i jego przycumowania do nabrzeża. W porcie Gdynia sytuacja taka zachodzi w okresie stycznia i lutego. Ogłaszana jest akcja lodowa, która ma umożliwić ruch w porcie. Zachodzi konieczność torowania drogi przez holownik oraz pokruszenia lodu w okolicach miejsca cumowania statku. Do tego celu lepiej jest wykorzystać holownik z napędem azymutalnym, który stosując odpowiednie sposoby, może to uczynić sprawnie i skutecznie. W referacie wskazano sposoby realizacji z użyciem holownika z napędem ASD. Praktyczne działania miały miejsce w Porcie Gdynia w lutym 2011 r. z użyciem holownika Heros. Nabyto doświadczenie, które może być pomocne w następnych latach podczas akcji lodowych.

EN

It has formed a problem with a ship entrance to port and her mooring due to ice on open roads, outer harbor and port channels. It has happened in Gdynia port in January and February. Breaking ice action has been announced to make possible the movement in the port. It has proceeded a necessity of clearing the way for ship by tug and ice crushing in the ship mooring spaces. It is better to use the ASD tug, which using suitable methods, can do it efficiency and effectively. In the paper it was presented the realization methods with using ASD tug. Practical performances have been take the place in Gdynia port in February 2011 with tug named Heros. It was acquired the experience, which may be helpful in the next years during ice crushing actions.

12

Zmienność zlodzenia wybranych rzek Arktyki w XX wieku

Grześ M., Ćmielewski M.

Problemy Klimatologii Polarnej

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2008

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nr 18

69-78

PL

W artykule przedstawiono zmienność czasu trwania pokrywy lodowej na 17 dużych rzekach Arktyki. W drugiej połowie XX wieku czas trwania pokrywy lodowej uległ wyraźnemu skróceniu o 21-28 dni na 100 lat. Na czterech rzekach (MacKenzie, Pieczenga, Peczora, Titowka i Taz) czas trwania pokrywy lodowej uległ wydłużeniu nawet o 33 dni na 100 lat. Skrócenie czasu trwania związane jest z późniejszym formowaniem się pokrywy lodowej oraz z jej wcześniejszym rozpadem. Należy przypuszczać, że zmienność czasu trwania zjawisk lodowych jest dobrym wskaźnikiem zachodzących w Arktyce zmian klimatu. Ze skróceniem czasu trwa-nia zjawisk lodowych wiąże się wydłużenie okresu nawigacyjnego.

EN

Trends and fluctuations in the dates of ice cover formation and breakup on selected rivers in the Arctic worked out based on databases: Benson B., Magnuson J., 2000, Global lake and river ice phenology database; Vuglinsky V., 2000, Russian river ice thickness and duration; National Snow and Ice Data Center, 1998, Nenana Ice Classic: Tanana River ice annual breakup dates. Most of the Arctic rivers are frozen for 7-8 months. Dissimilarity of flow conditions during ice cover period, ice jams and dams allow to state that it is the most important part of the Arctic rivers hydrological regime. The main problem in comparison of ice events and determine its trends are heterogeneously data series. Data are selected to be the most similar. In this study are used homogeneous and comparable series for period 1958-1990. For analysis have chosen 17 rivers situated in different Arctic areas. 3 are in Europe, 10 on Siberia and the others 4 in Canadian Arctic and on Alaska. For all of them was calculated average time of ice cover duration, dates of freezing and breakup and trends of this parameters. Difference between ice cover duration on the Arctic rivers is 64 days. The longest time of ice cover duration is on Anabar – 248 days. The shortest, 184 days, on Yukon in Dawson. Average time of ice cover duration on most part of the rivers is more than 200 days. The earliest date of freeze-up is on Anabar river, average 2 October. To the end of the month ice cover is on most of the rivers. At the beginning of November come out on MacKenzie, Yukon and Pechenga rivers. Breakup starts 5 May (Tanana river). To the end of May ice cover vanish on most of the rivers. Exceptions are rivers in Eastern Siberia and Coppermine river, where spring ice drift starts latest, average 18 June. Differences between freeze-up dates amount 40 days, while between breakup on various rivers 44 days. Ice cover duration trends are diverse but generally on most of the rivers trends are negative (for 11 of 16 rivers). The biggest trend was on Yukon river in Dawson in 1970-90 (–24.2 days/100 years). A little bit smaller trend (–23.7 days/100 years) was on Ob (1958-90) and Anabar (–21.8 days/100 years). Positive values characterized rivers: MacKenzie, Pechenga, Pechora and Taz, which had a biggest value (33.2 days/100 years). Freeze-up on the Arctic rivers occurs later and later. It is described by positive value of this parameter. It fluctuates within 0.9 days/100 years on Anabar to 18.9 days/100 years on Coppermine. However in two stations in the Canadian Arctic, 3 in European Arctic and on Lena ice cover freeze-up more and more early. Only two rivers: Yndigirka and Pechora freeze-up later and later (it is 2.7 days/100 years on Yndigirka and 15.7 days/100 years on Pechora). On the others rivers trends are negatives and fluctuates within 0.2 days/100 years (Coppermine) to 47 days/ 100 years (MacKenzie in Fort Good Hope). Presented trend’s values are different from this presented by Magnuson et al. (2000), who compared freezing dates for lakes and rivers together for all the northern hemisphere.

13

Kurczenie się pokrywy lodowej na Ziemi w wyniku zmian klimatycznych

Goldsztejn P.

Ekotechnika

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2006

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nr 3

49-53

PL

W wyniku ciągłego zwiększania się temperatury powierzchni Ziemi w ciągu XX wieku, w ostatnim półwieczu na całym świecie obserwowany jest proces przyspieszonego topnienia lodowców i lądolodów. W niniejszym artykule opisano zmiany temperatury powierzchni Ziemi w aspekcie globalnym oraz przedstawiono ich prawdopodobne przyczyny. Szerzej zaprezentowano także najbardziej widoczne efekty tych zmian - sukcesywnie zmniejszające się zasięgi lodowców w obrębie większości masywów górskich, zwiększającą się z roku na rok powierzchnię topnienia lądolodu Grenlandzkiego i Antarktydy oraz coraz mniejszy zasięg lodu pływającego Arktyki.

14

Stan termiczny Atlantyku Północnego a zlodzenie mórz Barentsa i Grenlandzkiego (1972-1994)

Styszyńska A.

Problemy Klimatologii Polarnej

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2004

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nr 14

39-57

EN

This work deals with correlations between anomalies in SST (sea surface temperature) in the North Atlantic and the sea ice area of the Barents and Greenland seas. This research made use of mean monthly sea ice cover with density >= 10% observed in the Barents and Greenland seas over the period 1972-1994 (calculated on the bases of weekly area of sea ice cover of the above mentioned seas collected in NCDC data set ?1972-1994 Sea Ice Historical Data Set?). The thermal condition of the North Atlantic is characterised by the values of anomalies in mean monthly sea surface temperature (SST) in so called ?controlled grids? (2° x 2°) selected/appointed here by A.A.Marsz (1999a, 2001). Their location is presented in Fig.1. A standard statistical analysis has been used in this research (correlation analysis, regression analysis). The strongest synchronic correlations (observed in the same months) with the sea ice cover of the said seas have been noted in grids located north of the North Atlantic Current and characterising the following waters (Tables 1 and 2): of the Labrador Sea (located within the range of Labrador Current activity) - [50,52], those north of the Gulfstream delta - [40,52] and those located inside the circle of the cyclonic circulation of the North Atlantic - [30,54]. The highest coefficient values of linear correlation, at a level p<0.05 exceeding the statistical significance, were noted in winter months (December, January, February) and those spring ones (April, May, June) as well as in summer - in July and August (the Greenland Sea). There are also several asynchronic correlations. The results of analysis of multiple regression between the SST anomalies and the area of the sea ice cover indicated that the sea areas in which the changeability in their thermal condition has the greatest influence on the formation of the sea ice cover of the said seas are located in the western part of the North Atlantic.

15

Związki bilansu masy lodowców w rejonie Kongsfjordu (NW Spitsbergen) z pokrywą lodową mórz Grenlandzkiego i Barentsa

Styszyńska A.

Problemy Klimatologii Polarnej

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2002

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nr 12

133-146

EN

The sea ice cover of the Greenland and Barents seas is characterised by great seasonal and interannual changeability which has influence on radiation and heat balance of that region. This changeability is directly observed in changes in atmospheric circulation and further noted in changes in meteorological elements (mainly in air temperature, cloudiness, precipitation and wind). Changes in weather conditions determine both the value of losses of glacier masses in a given balance year and the value of ice masses accumulation. This article tries to find the answer to a question if and to what extent the variability of the extent and rate of the Barents and Greenland seas ice formation is directly reflected in changeability of glaciers masses balance in the region of Spitsbergen. This research was based on the mass balance of two small glaciers located in the region of Kongsfjord, i.e. Austre Brogger and Midre Lovén. The mean monthly values of sea ice cover observed in the Greenland and Barents seas in the period 1972-1994 were used in this research (the values calculated on the basis of 1-week values of these seas ice cover taken from NCDC - Asheville). The values of winter, summer and net balances of the said glaciers were drawn from article by Lefauconnier et al. (1999). In addition, the correlation was examined between the balance Austre Brogger and Midre Lovén glaciers and the changeability of atmospheric circulation described by Niedźwiedź ?circulation types? (2001). The research made use of standard statistical analysis (correlation and regression analysis). Statistically significant correlations have been noted between the values of winter balances of both examined glaciers and the size of ice cover of the Barents and Greenland seas at the initial stage of its formation - in November (r ~ -0.55÷0.64, adj. R2 ~ 0.30÷0.35). The result of analysis of multiple regression indicated that the strongest correlation with ice cover of the Greenland Sea occurs in September, whereas in the Barents Sea in December (R ~ 0.70÷0.83). Changes in sea ice cover observed in that time explain 44% and 65% of changeability in winter balance of Austre Brogger and Midre Lovén glaciers, respectively. These results suggest that the process of heat transfer from the ocean to the atmosphere may by very intensive when the sea is merely covered with ice in the areas on the way of main directions of air mass advection. This will provide favourable condition for clear domination of sea air masses resulting in the increase in air temperature (Styszyńska 2000) and precipitation in the region of NW Spitsbergen. The summer balance of the examined glaciers is influenced by the changes in ice conditions only to a small extent. The only significant correlation with sea ice condition of the Greenland Sea was noted in August. Lack of the discussed correlation in summer is attributed to the influence of insolation and radiation factors whose importance increase during the polar day (as indicated in research by Lefauconnier et al. (1999)).

16

Zmiany zlodzenia mórz Grenlandzkiego i Barentsa w świetle zmian wskaźnika intensywności Prądu Labradorskiego (1972-1994). Wstępne wyniki analizy

Styszyńska A.

Problemy Klimatologii Polarnej

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2001

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nr 11

93-104

EN

The Barents and Greenland seas are characterised by great seasonal and interannual changeability in the ice cover. Research carried out by many authors prove that the ice regime of these seas is influenced, to a great extent, by large scalę changes in atmospheric circulation and by the ocean surface circulation of the North Atlantic and the Arctic Ocean. Such correlations arę mainly of teleconnection type and show phase shifts (among others Mysak 1995, Deser et. al. 2000). One of the elements of the sea surface circulation of the Atlantic Ocean is the Labrador Current. The intensity of this current changes in time. In the periods when the Labrador Current becomes strong, its waters form vast anomalies in the sea surface temperaturę in the NW Atlantic. Further they spread eastwards along the north edge of the North Atlantic Current and with some delay, have influence on the atmospheric circulation in the central and east part of the North Atlantic (Marsz 1997, 1999). The way how the changes in the intensity of the Labrador Current influence the climate nas not been discovered yet. The intensity of this current can be defined by means of an index (WPL - Labrador Current Intensity lndex) established by Marsz (Internet). This work examines if there is direct correlatton between the changes in the sea-ice cover of the Barents and Greenland seas and the variability of the intensity index of the Labrador Current. The research madę use of homogenous data concerning a week-old sea ice cover observed at the analysed seas and the values of intensity index of the Labrador Current in the period January 1972 until December 1994 given by Marsz (obtained from NIC and NCDC - Asheville). It has been stated that over the examined 23-year period (1972-1994) the mean monthly the sea-ice cover in the Barents Sea indicates to strong correlation with the changes in the value of the intensity index of the Labrador Current (Table 1, Fig. 1). The changes in WPL result in the rhythm of changes in the sea-ice cover of the Greenland Sea only in winter (Table 2, Fig. 2). The occurrence of anomalies in the sea surface temperatures in the region SE of New Foundland seem to have great influence on the later formation (after few or several months) of the sea-ice cover in the Barents Sea (Fig. 1, 3. 4, formula 1-3). Changes in the intensity of Labrador Current in a given year explain 30% up to 50% changeability of the sea-ice cover developing in that sea from January to July in the following year (Table 1, Fig. 3). The area of the sea-ice cover in the Greenland Sea is mainly influenced by the intensity of the Transpolar Drift and East-Greenland Current transporting considerable amount of ice from the Arctic Ocean. Only during fuli winter season, from January to March, the correlation between the intensity of the Labrador Current and the sea-ice cover reaches statistical significance (Table 2). The results of the carried out analysis point to significant influence of advection factor on the sea-ice cover of the examined seas. In both analysed seas the phenomenon is connected to both the character and intensity of the Atlantic waters flow and to greater frequency of occurrence of specified forms of air circulation in the region of central and eastern part of the North Atlantic, possible at a given distribution of anomalies in surface waters of the North Atlantic.

17

Zlodzenie Zatoki Admiralicji a temperatura wody w energoaktywnej strefie Morza Bellingshausena (1982-1997)

Kruszewski G.

Problemy Klimatologii Polarnej

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2001

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nr 11

105-112

EN

Correlations, especially those on a regional scale, between the sea ice cover formation and the air and sea surface temperatures have been pointed out by a number of authors. Region that is clearly marked by such correlation is located NW of the Antarctic Peninsula (among others Weatherly and others, King 1994, Styszyńska 1997, 2000). The intensity of ice formation in the relatively small Admiralty Bay noted in a given winter season indicates strong correlation with the winter sea ice cover extent in a regional scale (Kruszew-ski 1999, 2000). This ice cover is influenced (among others) by the sea surface temperature. The possible nature of the correlation between the sea surface temperature (SST) at the meridian of 080°W and the changes in air temperature in the region of the Southern Shetlands as described by Styszyńska suggested the presence of similar correlations with the intensity of ice formation in that region, so in this way also in the Admiralty Bay. With the help of Spearmann correlation coefficient a number of statistically significant relations have been found between the course of SST in the region of 086-062°W and the intensity of ice formation in the Admiralty Bay are presented in a categorised way. These relations are both synchronic and asynchronic. The synchronic correlation is observed mainly between SST in winter months and the ice cover category in the same year (the increase in SST is followed by the decrease in ice cover category).These correlations are most significant in the region 62-66°S (July - September). They also occur farther north 56-58°S but this time in the eastern part of the said region (March-July) and they are also observed in 60-64° (but in January and February). The asynchronic correlations have been observed between SST in October and ice cover category of the Admiralty Bay in the following year(8-11month slater). These correlations are most significantly marked in 56-64°S (the northern part of the Bellingshausen Sea and in the Circumpolar Current region) especially in 60°S 080°W (r = -0.677, p < 0.01) and their character is similar to those of the previously mentioned synchronic correlations.

18

Glacials, interglacials and ice covers

Stankowski Wojciech

Geologos

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2000

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Vol. 5

189--195

EN

A stratigraphic approach to the Quaternary which takes into account the changes in climate (Pleistocene cold stages = glacials, and Pleistocene warm stages = interglacials, with considerable variations in temperature and humidity), and appearance and disappearance of ice sheets in certain areas. Reduced ice sheets might have remained during the interglacials.

19

Związki temperatury powietrza w rejonie Półwyspu Antarktycznego ze zmianami wielkości pokrywy lodowej mórz Amundsena, Bellingshausena i Weddella (1973-1996)

Styszyńska A.

Problemy Klimatologii Polarnej

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1999

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nr 9

193--233

EN

This article deals with the relationship between air temperature in the region of the Antarctic Peninsula and the changes in the sea ice cover of the seas adjacent to West Antarctida. The Bellingshausen and Amundsen seas are characterised by large variability in the sea ice cover both a within one year and from year to year (see tab. 3-5, Fig. 1-3). Synchronic correlations occurring between the ice edge and the air temperature observed at 14 chosen meteorological stations in the region of the Antaretic Peninsula (see tab. 1) have been analysed in this work. The above mentioned analysis used the data concerning the northern extent of the Antarctic sea ice cover (concentrated - 10% and more) at each 10 degrees of longitude worked out by TH. Jacka for the period 1973-1996 and the monthly mean air temperatures at the chosen stations for the same observational period taken from the Climate Data Sets worked out by the same author and completed by the Monthly Climatic Data for the World. The examination of synchronic correlations between the ice edge at different degrees of longitude and the air temperature at the chosen stations pointed to a number of statistically significant correlations occurring in different regions. The air temperature at the stations located on the western coast of the Antarctic Peninsula and the South Shetlands pointed to strong, statistically significant correlations wit h the winter and spring ice cover in two regions (see tab. 6-11). In the direct vicinity of the Antarctic Peninsula (500-70"W) these correlations were positive and farther west, in the region 1100-150oW, these correlations were also strong but negative. The most southward located stations, i.e. Faraday, Rothera and San Martin also in summer and autumn showed strong negative correlation between ice edge but with the region located more westward 1600W -180° (see tab. 6-5). Similar characteristic features of the distribution of the examined relationship were observed at the Signy, Orcadas and Grytviken stations located on the Weddell Sea. The statistically significant positive correlations occurred in the direct vicinity of the above mentioned stations and similar but negative correlations in the region of 1300-1600W (see tab. 11). At the Esperanza and Marambio stations located in the northern part of the Antarctic Peninsula and the Punta Arenas which is far northwards, the air temperature showed only few significant correlations with the ice edge distribution occurring in different seasons of a year. The results of the analysis pointed to the following conclusion that the changes in the air temperature at the stations of the Antarctic Peninsula were influenced not only by the changes in the winter and spring ice cover in the closest vicinity of these stations but also by the changes occurring in the farther areas. The defined in the course of this analysis area, i.e. 130°-150°W seems to be one of the important centres where the interaction between the ocean and the atmosphere takes place.