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1

Cyrkulacyjne uwarunkowania występowania mgieł na wybranych lotniskach w Polsce

Śmigiera Sylwia

Przegląd Geofizyczny

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2021

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Z. 1-2

65--83

PL

Celem pracy jest określenie wpływu cyrkulacji atmosfery na występowanie mgieł na wybranych lotniskach w Polsce. Wykorzystano dane z okresu 1981-2015, obejmujące liczbę godzin z mgłą w poszczególnych dniach na stacjach w Szczecinie, Gdańsku, Poznaniu, Warszawie, Wrocławiu, Krakowie i Rzeszowie. Typy cyrkulacji atmosferycznej zostały opisane zgodnie z typologią J. Lityńskiego. Dodatkowo wykorzystano dane uzupełniające, obejmujące Numeryczny Model Terenu (DEM), mapy sieci rzecznej i zbiorników wodnych w Polsce oraz mapę pokrycia terenu CORINE Land Cover 2012. Z przeprowadzonych analiz wynika, że istotną rolę w występowaniu dni z mgłą odgrywają kierunki adwekcji powietrza. W większości przypadków najwięcej dni z mgłą występowało podczas adwekcji powietrza z kierunków południowych, a najmniej z północnych, niezależnie od pory roku. Zróżnicowanie przestrzenne występowania mgły w określonym typie cyrkulacji jest spowodowane między innymi wpływem warunków lokalnych. Największy wpływ wykazują rzeźba terenu i obecność zbiorników wodnych.

EN

The aim of this paper is to examine the influence of atmospheric circulation on the occurrence of days with fog at the airports in Poland. The data included the number of hours with fog on particular days in the period of 1981-2015 on the stations in Szczecin, Gdańsk, Poznań, Warszawa, Wrocław, Kraków and Rzeszów. The study uses the circulation typology by J. Lityński. Additionallny, Digital Elevation Model, map of rivers and water reservoirs in Poland and land cover map CORINE 2012 were used in this research. The occurrence of days with fog in particular circulation types was assessed with the frequency and conditional probability. It was found that the directions of air advection play an important role in the occurrence of days with fog. In most cases the most days with fog occurred during air advection from southern directions and the least from northern ones. The spatial diversity of fog occurrence in a given type of circulation is caused by the influence of local conditions. The strongest influence is exerted by the relief and the presence of water reservoirs.

2

Cyrkulacyjne uwarunkowania występowania mgieł i ograniczonej widzialności w Hornsundzie (Spitsbergen)

Łupikasza E., Niedźwiedź T.

Problemy Klimatologii Polarnej

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2016

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Nr 26

5--16

PL

W artykule omówiono przebieg roczny występowania mgieł i ograniczonej widzialności poziomej (<1km) w Hornsundzie. Wykorzystano w tym celu dane o zjawiskach meteorologicznych w okresie od lipca 1978 do połowy listopada 2016 roku. Zbiór danych poszerzono o wyniki bardzo dobrej jakości obserwacji zgromadzonych podczas Międzynarodowego Roku Geofizycznego (lipiec 1957 – sierpień 1958). W Hornsundzie mgły występowały średnio podczas 34 dni w roku. Częściej, bo przez 55 dni, widzialność pozioma była ograniczona poniżej 1 km. Zjawiska te najczęściej pojawiały się latem (średnio 21 dni), zwłaszcza w lipcu podczas dni z adwekcją powietrza z południowego zachodu. Dysproporcja pomiędzy częstością występowania dni z mgłą i ograniczoną widzialnością była niewielka latem i osiągała maksimum w zimie kiedy widzialność pozioma jest ograniczona głównie przez intensywne opady śniegu lub zawieje i zamiecie śnieżne. W zimie największym prawdopodobieństwem występowania mgły (8 %) wyróżniała się sytuacja synoptyczna z centrum wyżu nad Spitsbergenem (typ Ca), zaś prawdopodobieństwo wystąpienia ograniczonej widzialności w typach cyklonalnych było większe (18%) niż w typach antycyklonalnych (6%).

EN

Data on meteorological phenomenon from Polish Polar Research Station in Hornsund were used to recognize the annual course of fog days and days with horizontal visibility <1km and their relation to atmospheric circulation. Fog occur relatively often in the Arctic being noticed on 34 days a year. Days with limited horizontal visibility are even more frequent (55 days). The highest frequency of the phenomenon falls in summer (21 days), with the clear maximum in July (9 days), mainly on days with south-western air advection. On such days probability of the phenomenon in anticyclonic situation (SWa 56%) is 11% higher than in analogous cyclonic situation (SWc 45%). In summer the frequencies of fog and horizontal visibility <1km are similar. In other season disproportion in the frequency of these phenomena is bigger, particularly in winter. This indicates that in summer the limited visibility is usually due to fog while in other seasons it is related to intense snow precipitation, blowing snow or blizzards. South-western flow of air masses also favours the occurrence of fog and limited horizontal visibility in autumn. In spring these relations are slightly different. The highest probability of the phenomena is related to air advection from the west. Fog occurrence is favoured by Wa type (22%), while limited visibility is related to Wc type(31%). In winter fog probability increases on days with anticyclone centre located over Spitsbergen (Ca 8%). In these season the relation between fog occurrence and atmospheric circulation are quite different than between limited visibility and atmospheric circulation. Limited visibility probability in cyclonic situations (18%) is higher than in anticyclonic (6%), with the maximum in SEc (37%) and Cc (31%) types. In winter visibility is mainly limited by intense snow precipitation, blowing snow and blizzards, which are related to low pressure systems.

3

Dynamika wskaźników cyrkulacji nad Spitsbergenem

Niedźwiedź T., Łupikasza E.

Problemy Klimatologii Polarnej

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2015

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Nr 25

153--167

PL

Artykuł dotyczy wieloletnich zmian cyrkulacji atmosfery nad Spitsbergenem opisanej za pomocą trzech syntetycznych wskaźników cyrkulacji – wskaźnika cyrkulacji strefowej W, wskaźnika cyrkulacji południkowej S oraz wskaźnika cykloniczności C – wyznaczonych na podstawie częstości występowania typów cyrkulacji nad Spitsbergenem. W odpracowaniu wykorzystano chronologiczne ciągi wymienionych wskaźników za okres od grudnia 1950 do września 2015 roku. Artykuł jest aktualizacją wcześniejszych opracowań publikowanych w latach 2001 i 2006. Pomimo iż Spitsbergen leży w strefie dominacji wiatrów wschodnich to w okresie badawczym stwierdzono istotny statystycznie wzrost częstości adwekcji powietrza z zachodu oraz wzrost częstości występowania układów niżowych w skali roku. Istotny wzrost występowania sytuacji niżowych stwierdzono również w większości sezonów z wyjątkiem lata. Cyrkulacja strefowa (wskaźnika W) nie podlegała istotnym statystycznie zmianom w rozpatrywanym okresie. Kierunek trendów wskaźnika cyrkulacji południkowej S zmieniał się w zależności od pory roku, przy czym statystycznie istotny był jedynie wzrostowy trend zimą wskazujący na wzrost nasilenia napływu powietrza z sektora południowego.

EN

This paper discusses long-term variability of atmospheric circulation over Spitsbergen using three complex circulation indices – zonal circulation index W, meridional circulation index S and cyclonicity index C. The indices were calculated on the basis of the frequency of circulation types occurrence over Spitsbergen. Chronological series of circulation indices covering the period from December 1950 to September 2015 were used. This paper is an update of previously published papers in 2001 and 2006 on the changes in atmospheric circulation over Spitsbergen. Although Spitsbergen is located in the zone of eastern winds dominance, significant increase in the frequency of air advection from the west and increase in the frequency of low pressure systems were found on annual scale. Significant increasing trends in the frequency of cyclonic types were also found in every season except for summer. Trends in W index were not statistically significant on seasonal scale. Direction of trends in meridional circulation index (S index) is diversified depending on season however significant changes were only found in winter indicating an increase in the air advection from the southern sector.

4

Występowanie dni z przejściem temperatury powietrza przez 0°C na wybranych stacjach w atlantyckim sektorze Arktyki

Łupikasza E., Niedźwiedź T., Małarzewski Ł.

Problemy Klimatologii Polarnej

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2013

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Nr 23

121--135

PL

Opracowanie dotyczy ważnego wskaźnika współczesnych zmian klimatu – dni z przejściem temperatury powietrza przez 0°C, które wyróżniono na podstawie temperatury dobowej maksymalnej i minimalnej mierzonej na 4 wybranych stacjach w obrębie atlantyckiego sektora Arktyki w okresie regularnych pomiarów instrumentalnych. Analiza częstości występowania tych dni w kolejnych miesiącach wskazuje na ich bimodalny przebieg roczny z maksimum w maju lub czerwcu, a minimum w lipcu lub sierpniu. Obliczona metodą Mann- Kendalla istotność tendencji wykazała spadek częstości występowania dni z Tmax>0°C i Tmin<0°C w miesiącach z cieplejszej części roku oraz w grudniu. Czasowe zmiany występowania tych dni zależą od lokalnej cyrkulacji atmosfery – najsilniej od napływu powietrza z południa, który w lecie przyczynia się do spadku, zaś w zimie do wzrostu ich frekwencji.

EN

This study aims at determining the occurrence of days with freeze-thaw events at selected meteorological stations (Svalbard Lufthavn, Hornsund, Hopen, Bjørnøya) representing the Atlantic sector of the Arctic, recognizing the trends in the frequency of these days and their relation to atmospheric circulation. The days with freeze-thaw events (TD0) were selected on the basis of daily minimum and maximum air-temperature during the period of regular instrumental measurements conducted at particular stations – Hopen: November 1946 – March 2013, Bjørnøya: January 1946 – March 2013, Svalbard Lufthavn: January 1957 – March 2013, Hornsund: July 1978 – March 2013. Basic descriptive statistics were used to investigate the annual course of the days with freezethaw events (Tmax>0°C and Tmin<0°C) occurrence in the period 1979-2012 which allowed the comparison of the statistics between the stations. Statistical significance of trends were checked with Mann-Kendall test whereas the trends magnitudes were calculated with the least square method and expressed as a change in the number of days per 10 years. Spearman correlation coefficients were calculated to assess the relations between the DT0 occurrence and atmospheric circulation. Three local circulation indices (S index, W index, C index) and one macroscale circulation index (AO index) were taken into consideration. Statistical significance level of 0.05 was used for both trends and correlations coefficients. The trends were calculated for three various periods: the period of regular instrumental measurements – various at particular stations, the period 1979-2012 – common for all stations analysed and 1995-2012 which is the period of dramatic warming of the Arctic (Przybylak 2007). The investigations were conducted from monthly, seasonal (winter – Dec, Jan, Feb; spring – Mar, Apr, May; summer – Jun, Jul, Aug; autumn – Sep, Oct, Nov) and annual perspective. Days with freeze–thaw events are considered as an indicator of current climate change primarily manifesting in the rapid increase of air-temperature. The average annual number of days with freeze-thaw events varied depending on station from 63 days to 96 days in the period of 1979-2012. These days occurred during the whole year with the maximum in autumn (Svalbard Lufthavn, Hornsund and Hopen) or spring (Bjørnøya) and the minimum in summer (Svalbard Lufthavn, Hornsund, Bjørnøya) or winter (Hopen). The annual course of the number of days with freeze-thaw events is bimodal with the first rate maximum in May (Svalbard Lufthavn, Hornsund, Bjørnøya) or June (Hopen) and the secondary maximum in October. The clearest changes (increase) in the frequency of DT0 occurrence were found in Hopen and Bjørnøya in the months belonging to the warmer part of a year – July, August, September. In Svalbard Lufthavn and Hornsund significant increase in the frequency of DT0 was detected in June. In December increasing trends in the DT0 occurrence were significant which also applies to January DT0 trends at both Longyearbyen and Bjørnøya stations. Dramatic increase of the air-temperature in the Arctic which began in the middle of the nineties has not influenced the frequency of days with freeze-thaw events – the trends calculated for the period of 1995-2012 were significant only in September and sporadically (single stations) in May and December. The long-term variability in the number of days with freeze-thaw events was significantly related to atmospheric circulation. The occurrence of such days was most influenced by the S circulation index, which determined the frequency of DT0 in majority of months and seasons despite summer. At the beginning of a year (February – March) the frequency of DT0 depended most on the flow of air from west (W circulation index). The cyclonity index (C index) affected the number of DT0 at Hopen and Bjørnøya stations. The impact of macroscale circulation (AO index) on the variability of DT0 was limited to Bjørnøya station in the case of monthly values and covered Hopen station in the case of seasonal values. Statistically significant correlation coefficients calculated for the warmer part of a year (from June to September) were positive and were negative for the rest months. Significant decrease of the DT0 frequency in September might be related to the strengthening of the northern flow.

5

Typ cyrkulacji atmosfery w regionie bydgosko-toruńskim podczas długotrwałej suszy meteorologicznej w latach 1989-1998

Bąk B., Maszewski R.

Woda-Środowisko-Obszary Wiejskie

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2012

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T. 12, z. 4

17-29

PL

W pracy przeanalizowano rozkład typów cyrkulacji atmosfery w regionie bydgosko-toruńskim, w czasie występowania długotrwałej suszy meteorologicznej, w okresie od VIII 1989 r. do IX 1998 r. Termin wystąpienia suszy określono na podstawie miesięcznych wartości standaryzowanego wskaźnika opadów SPI-48, obliczonych na podstawie znormalizowanych 48-miesięcznych sum opadów zmierzonych w Bydgoszczy w latach 1896-2000. Typy cyrkulacji dla regionu bydgosko-toruńskiego zdefiniowano na podstawie katalogu 21 typów sytuacji synoptycznych, według klasyfikacji Niedźwiedzia. Częstość poszczególnych typów cyrkulacji powietrza w okresie badanej suszy meteorologicznej, określono na podstawie kalendarza typów cyrkulacji, sporządzonego na podstawie codziennych dolnych map synoptycznych, publikowanych przez niemiecką służbę meteorologiczną Deutscher Wetterdienst. Klasyfikacje typów cyrkulacji dla poszczególnych dób dokonano na podstawie kierunku adwekcji, rodzaju układu barycznego i kształtu linii izobarycznych. Dla każdego miesiąca w okresie VII 1989-IX 1998 określono sumaryczny rozkład częstości poszczególnych typów cyrkulacji, który obejmował bieżący miesiąc suszy i 47 poprzedzających miesięcy. Stwierdzono, że średnia wartość SPI-48 w okresie VIII 1989-IX 1998 wynosiła -1,5 i była to najbardziej intensywna susza meteorologiczna w XX w. Wydzielono w niej trzy wielomiesięczne okresy najbardziej intensywnej suszy: ekstremalnej i silnej. W czasie trwania suszy najczęściej występowały typy cyrkulacji powietrza: Ka (klin antycyklonalny, rozmyty obszar podwyższonego ciśnienia, oś wału wysokiego ciśnienia) - 18%, Bc (bruzda cyklonalna, rozmyty obszar niskiego ciśnienia lub oś bruzdy niżowej) - 15% i Wc (cyklonalne sytuacje z adwekcją powietrza z zachodu) - 12%. Najrzadziej (w ok. 1%) występowały cyrkulacje z adwekcją powietrza ze wschodu. Stwierdzono istotną zależność między wartościami wskaźnika SPI-48 i wskaźnikami cyrkulacji strefowej W (r = -0,71), cyrkulacji południkowej S (r = 0,79) oraz między SPI-48 i wskaźnikiem cykloniczności C (r = 0,68).

EN

In the article was examined the distribution of types of air circulation in the region of Bydgoszcz-Toruń, during the occurrence of long-term meteorological drought in the period until VIII 1989 to IX 1998. The term of drought was based on monthly values of the standardized precipitation index SPI-48, which were calculated on the base of standardized 48-month total precipitation measured in Bydgoszcz in the years 1896-2000. Types of circulation for the region of Bydgoszcz-Toruń were defined on the basis of a catalog of 21 types of synoptic situation, which was adopted on the basis of classification proposed by NIEDŹWIEDŹ (1981). The frequency of each type of air circulation in the period examined meteorological drought, was defined on the basis of the calendar of circulation types, done on the basis of lower daily weather chart, published by Deutsche Wetter Dienst. Classification of circulation types for individual day was based on the direction of advection, the type and shape of barometric isobaric lines. For each month during the VII 1989-IX 1998 specified cumulative frequency distribution of various types of circulation, which included the current month drought and 47 preceding months. It was found that the average value of the SPI-48 in the period VIII 1989-IX 1998 was -1.5 and it was the most intense meteorological drought in the twentieth century. During the time of drought it was isolated three the periods of the most intense drought: extreme and strong. The most frequent types of air circulation were: Ka - 18% (anticyclonic wedge, sometimes a few unclear centres Or a blur area of high pressure, axis of ridge of high pressure), Bc - 15% (cyclonic trough, blur area of low pressure or axis of cyclonic trough with different direction of air advection and front systems dividing different air masses) and Wc - 12% (synoptic situations with air advection from the west). There was a significant correlation between the values of SPI-48 and the index of the zonal westerny circulation W (r = -0.71), index of southerly circulation S (r = 0.79) and between the SPI-48 and cyclonicity index C (r = 0.68).

6

Wpływ cyrkulacji atmosfery na występowanie dni z przejściem temperatury przez 0°C w Hornsundzie (Spitsbergen)

Łupikasza E., Małarzewski Ł., Niedźwiedź T.

Problemy Klimatologii Polarnej

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2012

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nr 22

5-16

PL

Dni z przejściem temperatury przez 0°C (Tmin<0°C i Tmax>0°C) są ważnym wskaźnikiem współczesnych zmian klimatu. W obszarach polarnych przekroczenie wspomnianego progu termicznego ma istotne znaczenie ze względu na uruchamiające się wówczas procesy zamarzania wody i tajania lodu. Celem niniejszego artykułu jest określenie wieloletnich zmian występowania dni z Tmin<0°C i Tmax>0°C oraz zbadanie relacji pomiędzy ich występowaniem a makroskalową cyrkulacją atmosfery w Hornsundzie, na podstawie dostępnych danych. Dni z przejściem temperatury przez 0°C w Hornsundzie pojawiają się w ciągu całego roku. Ich występowanie podlega istotnym statystycznie różnokierunkowym zmianom w czerwcu (trend ujemny) i w grudniu (trend dodatni), a kierunek tych zmian wykazuje związek ze średnią miesięczną temperaturą powietrza oraz jej wzrostową tendencją. Relacje pomiędzy występowaniem dni z przejściem temperatury powietrza przez 0°C a cyrkulacją atmosfery zmieniają się w przebiegu rocznym. W miesiącach zimowych (grudzień, styczeń, luty, marzec) oraz w kwietniu, październiku i listopadzie występowaniu dni z przejściem temperatury przez 0°C najbardziej sprzyja adwekcja powietrza z południa (S, SW i W) bez względu na rodzaj układu barycznego. W sierpniu, kiedy zależności wystę-powania dni z Tmin<0°C i Tmax>0°C od cyrkulacji atmosfery są bardzo wyraźne, oraz w lipcu, ich występowanie związane jest z napływem zimnego powietrza z NW i W, szczególnie podczas zalegania wyżu.

EN

Days with freeze-thaw events at which air temperature crosses the threshold of 0°C (Tmin<0°C and Tmax>0°C) are regarded as an important index of climate change. In the Polar Region such thermal conditions trigger the processes of water melting and freezing. This paper aims at the recognition of the variability and changes in the frequency of days with Tmin<0°C and Tmax>0°C as well as the relationships between their occurrence and macro scale circulation on the basis of available data. Days with freeze-thaw events occur throughout the year. Statistically significant trends in the occurrence of such days were found in June (downward trend) and December (upward trend). The directions of the trends are related to the magnitude of the average monthly temperatures and their growing tendencies. Relationships between the occurrence of days with Tmin<0°C and Tmax>0°C and atmospheric circulation change seasonally. Regardless of the type of baric centre, the warm air advection from the south-west sector (S, SW, W) favours the occurrence of such days in the winter half-year months (November-April) as well as in October. In August, when the relation between days with freeze-thaw events and atmospheric circulation is evident, as well as in July, the occurrence of the days concerned is linked to the inflow of cold air from the NW and W directions, particularly when Spitsbergen is influenced by the anticyclone.

7

Wpływ cyrkulacji atmosfery na występowanie dni mroźnych w Hornsundzie (Spitsbergen)

Niedźwiedź T., Łupikasza E., Małarzewski Ł.

Problemy Klimatologii Polarnej

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2012

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nr 22

17-26

PL

Dni mroźne, definiowane jako dni z Tmax<0°C są jednym z termicznych wskaźników współ-czesnych zmian klimatu. Celem artykułu jest określenie wieloletnich zmian częstości występowania dni mroźnych w Hornsundzie oraz określenie relacji pomiędzy ich występowaniem i cyrkulacją atmosfery. Badania przeprowa-dzono na podstawie dostępnych danych dobowej maksymalnej temperatury powietrza (26.07.1957-16.08.1958 MRG; 4.07.1978-29.02.2012). Średnio w Hornsundzie notuje się 183 dni mroźnych w roku. Najczęściej pojawiają się one w marcu, zaś w ogóle nie występują w lipcu i sierpniu. W badanym okresie częstość występowania dni mroźnych istotnie malała w maju, czerwcu i grudniu. Tendencja spadkowa dotyczy również rocznych wartości liczby dni mroźnych. Sezonowe zróżnicowanie relacji pomiędzy częstością występowania dni mroźnych a cyrkulacją atmosfery jest słabsze niż w przypadku dni z przejściem temperatury przez próg 0°C. W większości miesięcy największym prawdopodo-bieństwem ich wystąpienia charakteryzują się typy antycyklonalne: Na, NEa, Ea, NWa oraz Ca i Ka. Występowaniu dni mroźnych nie sprzyja adwekcja ciepłego powietrza z południa.

EN

Ice days defined as days with daily maximum temperature below 0°C are placed amongst the indices of current climate change. This paper aims at research both the long-term variability in the ice days occurrence and their relations to atmospheric circulation. All available data on daily maximum temperature were used (26.07.1957-16.08.1958 MRG; 4.07.1978-29.02.2012). On average, 183 ice days a year are noted in Hornsund. The highest number of the days occurs on March whereas they do not appear on July and August. The frequency of ice days were significantly lowering in May, June and August. The downward trend was also found in the annual index values. Seasonal differentiation of the relations between the ice days occurrence and atmospheric circulation are weaker than in case of days with freeze-thaw events. In majority months the highest probability of the ice days occurrence is linked to the six anticyclonic types (Na, NEa, Ea, NWa, Ca and Ka). Advection of warm air from south results in rarer ice days.

8

Charakterystyczne dla Hornsundu typy pogody a cyrkulacja atmosfery

Ferdynus J.

Problemy Klimatologii Polarnej

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2007

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nr 17

105-111

PL

W pracy przedstawiono zależności statystyczne pomiędzy frekwencją „charakterystycznych typów pogód” a wskaźnikami cyrkulacji Niedźwiedzia. Za „pogody charakterystyczne” uznano te, które w średniej rocznej strukturze stanów pogód pojawiają się rokrocznie oraz te które obserwuje w średniej wieloletniej strukturze każdego miesiąca. Przeprowadzona analiza wykazuje, że związki między frekwencją „charakterystycznych typów pogody”, a wskaźnikami cyrkulacji atmosferycznej są stosunkowo słabe.

EN

In this work there is presented statistical dependence between characteristic types of weather and Niedźwiedź’s circulation index (as characteristic weather was taken that when in average yearly weather condition structure the specific weather appears every year and the weather that can be observed in multi-yearly structure of each month). The analysis shows that relationship between frequency of „characteristic types of weather” and atmosphere circulation coefficients are relatively weak. Therefore it can be stated that circulation factor has little influence on the origin of specific types of weather. The origin of specific types of weather should be examined along with other factors, for example ice melting in the area of Spitsbergen. 111

9

Główne cechy cyrkulacji atmosfery nad Spitsbergenem (XII.1950 - IX.2006]

Niedźwiedź T.

Problemy Klimatologii Polarnej

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2006

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nr 16

91-105

PL

Praca omawia najważniejsze zmiany jakie zachodziły w cyrkulacji atmosfery nad Spitsbergenem w latach 1950–2006. Po analizie zmienności typów i wskaźników cyrkulacji Niedźwiedzia stwierdzono wyraźny wzrost wartości wskaźnika cyrkulacji zachodniej (zwłaszcza latem i zimą) i południowej (głównie zimą i latem) oraz wzrost aktywności niżów we wszystkich porach roku, a zwłaszcza w zimie. Gwałtowny wzrost intensywności cyrkulacji południowej, który wystąpił w styczniu i kwietniu 2006 r. zaznaczył się dużymi anomaliami termicznymi (12.4–12.6K powyżej średniej wieloletniej). Być może rok 2006 stanie się najcieplejszym w całym okresie obserwacji instrumentalnych temperatury na Spitsbergenie.

EN

The study presents variability of 21 circulation types and simple circulation indices above Spitsbergen for the period December 1950 – September 2006, based on original calendar of synoptic divided from the synoptic maps (Niedźwiedź 1992, 1997a). Classification of circulation types, based on method of H.H. Lamb (1972), used the direction of airflow (gradient wind) and pressure pattern (a – anticyclonic, c – cyclonic) as the main elements. After calculation of synoptic types frequencies the further results have been obtained using the simple circulation indices: W – westerly, zonal index, S – southerly – meridional index, C – cyclonicity index, as proposed by R. Murray and R. Lewis (1966) with some modifications (Niedźwiedź 1997b, 2001). The anticyclonic wedge (Ka – 10.5%) was the most frequent synoptic situation in the Spitsbergen (Table 1). The second one is circulation type Ec (9.9%) and NEc (8.7%). Weather and climate of Spitsbergen was modelled by the intense cyclonic activity during 56% of the days in a year (Fig. 1). The largest frequency of cyclonic types was noticed in November (67%). For May was typical the maximum frequency of the high pressure systems (59.7%). The annual variability of different airflows above Spitsbergen is presented on the Figures 2–5. The negative value of W index is typical for Spitsbergen, according to great frequency of eastern airflow (Table 2, Fig. 6). The great intensity of eastern airflow was observed from October to April, the weakest – during summer months. For the last 56 years was observed the increased tendency of index W. The most intense of southerly circulation index S was noticed on 1984–1994 (Table 3, Fig. 7). Positive trend was observed for winter, spring and summer. Only in autumn the tendency of S index was negative. For the Spitsbergen is typical predomination of cyclonic patterns (annual value of index C is +60), with highest values of index C from September to March (Table 4, Fig. 8). Only in May index C is negative (–10) thanks to great activity of anticyclones. For the last 56 years was observed the increasing activity of cyclonic weather above the Spitsbergen. For the last three years (2004–2006) was typical the concentration of extreme intensity of the particular forms of circulation, mainly in southerly one.

10

Rola cyrkulacji atmosfery w kształtowaniu temperatury powietrza w styczniu na Spitsbergenie

Niedźwiedź T.

Problemy Klimatologii Polarnej

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2004

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nr 14

59-68

EN

The study presents variability of simple circulation indices above Spitsbergen for the period 1899-2004 in January, based on original calendar of synoptic divided from the synoptic maps. After calculation of synoptic types frequencies the further results have been obtained using the simple circulation indices: W - westerly, zonal index, S - southerly - meridional index, C - cyclonicity index, as proposed by R. Murray and R. Lewis (1966) with some modifications, as well as Spitsbergen Oscillation (OS) defined as the standarized pressure difference between Bjornoya and Longyearbyen. The negative value of W index is typical for Spitsbergen, according to great frequency of eastern airflow. Variability of January temperature in Svalbard (t01SV) were investigated on the basis of averages from four stations: Isfjord Radio and Svalbard Lufthavn, as well as from Polish Polar Station in Hornsund Fiord on SW part of Spitsbergen, and from Bjornoya (Bear Island) - about 300 km SSE from Hornsund. After reconstructions of some lack data on the basis of linear regression, temperature data were obtained for the period of 1912-2004. For the temperature the main feature is period of cooling in the years 1912-1918 and then the great warming during the decade of 1930th (1933-1937). During the years 1937-1971 was observed the significant decreasing trend in January temperature to the cool period of years 1962-1971. The last period 1971-2004 has no any trend in temperature. But three large fluctuations took place with warm Januarys of 1972-1974, 1990-1992 and 1999-2001 and cool ones of 1975-1982, 1993-1998 and 2002-2004. Temperature of January changes in Spitsbergen depend on a great extend of circulation factors, mainly from the southern (S) and zonal circulation indices (W) or Spitsbergen Oscillation index (SO). Using the models of multiple regression was possible the recontruction of January temperature since 1899 on the basis of circulation indices. They explained about 63% of variance in temperature.

11

Współczesna zmienność cyrkulacji atmosfery, temperatury powietrza i opadów atmosferycznych na Spitsbergenie

Niedźwiedź T.

Problemy Klimatologii Polarnej

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2003

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nr 13

79-92

EN

The study presents variability of simple circulation indices above Spitsbergen for the period 1951-2002, based on original calendar of synoptic divided from the synoptic maps. After calculation of synoptic types frequencies the further results have been obtained using the simple circulation indices: W - westerly, zonal index, S - southerly - meridional index, C - cyclonicity index, as proposed by R. Murray and R. Lewis (1966) with some modifications. The negative value of W index is typical for Spitsbergen, according to great frequency of eastern airflow. Some complicated relations between above indices, NAO, temperature and precipitation were noticed in Spitsbergen. Variability of temperature and precipitation based on the data from Isfjord Radio and Svalbard Lufthavn stations, as well as from Polish Polar Station in Hornsund Fiord on SW part of Spitsbergen. They were compared with Bjornoya (Bear Island) - about 300 km SSE from Hornsund. For the temperature the main feature is period of cooling in the years 1961-1971 and around 1988, after the great warming during the decade of 1930th. During that coolest years also large annual temperature range was typical. The coldest was year 1968, and the warmest one -1984 (from -2 to -3°C). Next warm years were observed in 1990 and 1999, but in Jan Mayen the warmest was year 2002. The coolest winter (December-February) with average temperature below -20°C in Longyearbyen was in 1962/1963 (-21.5°C) and 1988/1989 (-20.1°C), and the warmest one on 1984/1985 (-8.3°C). Significant warming was noticed only in the warm half-year (V-X) about 1.2K since 1972 up to 2002. The warmest period V-X was in 1990, and coolest - in 1968. In summer (June-August) the temperature varied between 2°C in 1982 and 4.5°C (Hornsund) or 6.1°C (Longyearbyen) in 2002 (the warmest summer). Temperature changes in Spitsbergen depend on a great extend of circulation factors, mainly from the southern (S) and zonal circulation indices (W). The lowest temperatures were observed round the 1965. During the last decade of 1980 the period of little warming is observed again. For precipitation relative large increase of summer and September precipitation were noticed in the last years of the 20th century, mainly in 1994-1997. May be the part of its fallen in the form of snow in the upper parts of archipelago and supplied glaciers. The highest precipitation is typical for August and September. The largest diurnal precipitation totals - 58.3 mm was observed on August 1, 1994. The second high value 52.6 mm was noticed on September 6, 1996. During the observed period since 1978, only 5 time the daily precipitation in Hornsund exceeded 40 mm and 14 time were higher than 30 mm. In Hornsund annual total of precipitation twice exceeded 600 mm, in 1994 and 1996. This increase of precipitation was connected with greater frequency in the intensity of westerly and southerly atmospheric circulation expressed by the zonal and meridional circulation indices and the more intense cyclonic activity in autumn and winter seasons

12

Zagadnienie odtworzenia wartości bilansu Lodowca Hansa (SW Spitsbergen)

Marsz A. A., Styszyńska A.

Problemy Klimatologii Polarnej

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2002

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nr 12

117-131

EN

This article deals with an attempt to estimate the value of the net balance of Hansbreen (SW Spitsbergen).In order to estimate thes value an assumption has been made that the value of the net balance of Hansbreen is a function of two groups of factors, i.e. static and dynamic ones. The static elements (georgaphical location of Hansbreen, topography of the glacier and its surroundings, etc.) have no influence on the elements of the interannual changeability of the balance; a constant value will represent these elements in formulae. A group of dynamic factors that introduces an interannual changeability to the net balance is made up of a set of meteorological factors (mainly the course of air temperature, precipitation and cloudiness). The said meteorological factors are influenced by the character of atmospheric circulation. Because the main features of the character of the interannual changeability of the air circulation over that area are influenced by the spatial distribution of the anomalies sea surface temperature (SST), the analysis of variances has been chosen as the method used to define the direct statistical estimation of winter and summer balances as the function of monthly anomalies in SST occurring in the North Atlantic in a preceding period. As a result of statistical analysis, two linear functions of great statistical significance have been obtained, i.e. formula [1] and [2] enabling the estimation of winter and summer balances respectively. These functions use the values of anomalies in SST as independent variables. The influence of these values on the course of changeability in atmospheric circulation over the Nordic seas is obvious. The calculated values of the net balance of Hansbreen, estimated by means of the above mentioned functions and the values observed (Fig. 4) proved to be almost the same. Having the values of anomalies in SST (Reynolds data set) a sequence of values of net balance of Hansbreen has been estimated for the period 1970/71÷1996/97 (Table 2, Fig. 5) with the help of this method. An error of values calculated in this way can be found within limits ą0.106 m. water equivalent. The values of the calculated net balance taken from the above mentioned period were used to find by means of best estimating correlation between Hansbreen net balance and temperature and precipitation sums at Isfjord Radio station. Thanks to these results, the next sequence of values of Hansbreen balance for period 1926/27÷1969/70 (Table 3, Fig. 6) has been calculated. The final values are of no statistical significance and contain unknown errors. If they are close to reality it might mean that the balance of Hansbreen has been permanently negative since the end of the 20-ties.

13

Wpływ cyrkulacji atmosfery na wysokie opady w Hornsundzie (Spitsbergen)

Niedźwiedź T.

Problemy Klimatologii Polarnej

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2002

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nr 12

65-75

EN

Maximum daily precipitation and the number of days with precipitation 10.0 mm was analysed in Polish Polar Station in Hornsund (Spitsbergen), based on the measurements during 8008 days in the period 1978 June - 2000 July. The geographical coordinates of the station are following: j = 77°00? N, l = 15°33? E, Hs = 11 m a.s.l. This region is characterised by relatively large annual precipitation, varied from 230 mm in 1987 up to 640 mm in 1996. The largest diurnal total of precipitation - 58.3 mm was observed on August 1, 1994. The second high value 52.6 mm was noticed on September 6, 1996. During the observed period only 5 times daily precipitation exceeded 40 mm and 14 time was higher than 30 mm. Return period for possible daily precipitation greater than 70 mm is less than once in a hundred years. In the annual course the maximum of precipitation was observed mainly in August and September. Also the largest precipitation appears most often during the advection of air from the South and South-West with cyclones coming from the Atlantic Ocean. Special attention was made to the daily precipitation >=10 mm. they occurred during the 201 days (2.5%) and bringing about 35% of annual total. The probability of such events is highest in autumn (25%) during the south westerly cyclonic circulation type (SWc). Two other circulation types are caused also such precipitation: southern cyclonic type (Sc) with probability 24% and south westerly anticyclonic ones (SWa), with probability 11.5%. During the last decade of 20th century there was observed the increasing tendency in frequency of large precipitation in Hornsund. The sudden increase take place since 1994. These changes were connected with greater frequency in the intensity of westerly and southerly atmospheric circulation expressed by the zonal and meridional circulation indices.

14

Zmienność cyrkulacji atmosfery nad Spitsbergenem w drugiej połowie XX wieku

Niedźwiedź T.

Problemy Klimatologii Polarnej

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2001

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nr 11

7-26

EN

The study presents variability of different circulation indices above the Spitsbergen for the period 1951-2000. Investigated area covers the part of the Atlantic sector of the Arctic located between 75-80°N and 0-30°E. The study based on the original calendar of circulation types (Niedźwiedź 1981, 2001), prepared with the help of the synoptic maps of Europe (Europäischer Wetterbericht, 1976-2000, Tägliche Wetterbericht 1950-1975). Twenty circulation types have been distinguished. The advection directions are marked by the capital letters while the anticyclonic situations by the subscript a and the cyclonic ones by subscript c; for example, Wa and Wc denote the anticyclonic and cyclonic situations respectively, with the air advection from the West. Thus, there are 16 circulation types with definite directions of the air masses. The other 5 situations are nonadvective: Ca - centre of anticyclone, Ka - anticyclonic wedge, Cc - centre of cyclone, Bc - cyclonic trough, and x - col and the situations which cannot be classified. This classification is similar to Lamb (1972) types and based on methods described in the most important works in synoptic climatology (Barry an Perry 1974, Yarnal 1993). The frequencies of the occurrence of all the distinguished circulation types for the 50-years period of 1951-2000 are presented on the table 4. On the average, the anticyclonic wedge (Ka ? 10.4 %) is the most frequent in the Spitsbergen. The second one is situation Ec and NE occurs during 9.9 and 8.8% of the days. The centre of high pressure over Spitsbergen (1.3 % of the days) and the NW situation (1.5 % of the days) are the least frequent. Weather and climate of Spitsbergen are modelled by the intensive cyclonic activity during 56 % of the days in a year. The largest frequency of the occurrence of low pressure systems is characteristic for the period from September to March with maximum in November (66 %), December and January (65%). The number of days with high pressure systems exceeds 50 % only in May (59 %). The variability of circulation have been obtained using the simple circulation indices: zonal westerly circulation W index, similar to P progression index, index of southerly circulation - S, and index of cyclonicity - C, as proposed by R. Murray and R. Lewis (1966) with some modifications. The author of this paper calculated these indices for each year, season and month (tables 1-3). The most characteristic for Spitsbergen is the zonal form of circulation with the eastern component (W = -147 for a year) with the great intensity in the period from October to April (March ?20.9). The minimum in the eastern air-flow can be observed in summer (July +0.7). Another characteristic feature for Spitsbergen is predomination of the cyclonic patterns (index C = 56 for a year), especially in the period from September to March (November 12.8). In May the index C is negative (-9.4), which confirms the great activity of anticyclonic pattern. Among the southerly circulation forms the northern component dominates (index S = -36 for a year). Only in July and August the opposite situation can be observed. Circulation forms over Spitsbergen have been fluctuated in the long-term period. In 1951-2000 the greatest changes have been observed in the indices C and W (fig. 3-7). Significant increasing trend was observed in annual values of C and S indices. Southerly circulation index S is well connected with North Atlantic Oscillation (NAO) index (table 6). The best correlation between the mean temperature at Hornsund and circulation indices exists for the S index (table 7).

15

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.

16

Warunki meteorologiczne na Lodowcu Waldemara (NW Spitsbergen) w sezonie letnim 1999 roku

Kejna M.

Problemy Klimatologii Polarnej

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2001

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nr 11

55-65

EN

The meteorological measurements were carried out on NW Spitsbergen on the Waldemar Glacier (surface 2.66 km2) in three points: ATA (133 m a.s.l., marginal zone), LW1 (130 m a.s.l., snout of glacier), LW2 (380 m a.s.l., firn part). The base station of Toruń Polar Expedition is situated on the north part of Kaffioyra (KH, 11 m a.s.l.), about 3 km away from glacier. The air temperature and relative air humidity were measured by termohigrographs in standard meteorological boxes, and precipitation by Hellmanns pluwiometer in the period 14.07-8.09.1999. The weather conditions on the Kaffiöyra region are determined by solar and circulation factors. In the summer season 1999 north and east advection of air masses dominated. The meteorological conditions on Waldemar Glacier are formed by the influence of two contrasting environments: the glacier and its moraine foreground. The mean air temperature in summer 1999 at the Kaffiöyra equaled 5.4°C and at the moraine of the Waldemar Glacier (ATA) 5.2°C. On the glacier the air temperature was much lower, and on the snout (LW1) was 4.5°C and decreases with the altitude (LW2 3.2°C) . The average gradient of air temperature between LW1 and LW2 stands was 0.53°C/100 m. Between the warmed up dark moraine ground (ATA) and the melted surface of the glacier a ?thermal jump? occurred (0.4°C on the distance 160 m). The highest maximum of air temperature at KH was 18.1°C, and on the Waldemar Glacier 16.4°C (LW1) and 16.5°C (LW2). The relative air humidity on Spitsbergen are formed under the influence of oceanic water and foehn phenomena. In summer season 1999 the mean relative air humidity was 84% at the Kaffioyra and increased with the altitude on the Waldemar Glacier (LW1 ? 86%, LW2 ?89%). In the period 21-07-31.08 at the Kaffioyra sums of the precipitation equaled 58.4 mm and on the glacier: 85.2 mm (133 m a.s.l.), 100,6 mm (233 m a.s.l.), 108.9 mm (380 m a.s.l.) and 131.8 mm (421 m a.s.l.). In summer season the meteorological conditions on the Waldemar Glacier show a large variability. It is a result of incoming air masses, warm from moraine foreground up the glacier and cool from the glacier plateau, from the interior of Spitsbergen.

17

Metamorfoza pokrywy śnieżnej w rejonie południowego Spitsbergenu w sezonie 1992/1993

Leszkiewicz J., Głowacki P.

Problemy Klimatologii Polarnej

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2001

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nr 11

41-54

EN

Winter snow cover in south Spitsbergen is modelled by three main factors: snow precipitation, strong winds which blow out large amounts of snow (locally snow deposition occurs) and winter thaws of short duration. Slight snow melting during thaws causes development of ice-crust layers in a frozen snow cover. The ice-crust protects snow cover from blowing out. Moreover, ice-crust layers are very important in the investigations of snow stratigraphy. In the winter snow cover of 1992/1993, eight layers of ice-crust were observed. The occurrence of atmospheric precipitation is highly associated with the type of atmospheric circulation in the area of south Spitsbergen. In the analysis of statistic relations between circulation and precipitation, circulation typology of Niedźwiedź (1997) was applied. In the period June 1992 - May 1993, as many as 74% of annual solid precipitation was associated with the occurrence of three types of circulation (C-10, C-8 and C-3). The circulations C-4, C-6 and C-1 gave only 4% of annual precipitation. The winter season 1992/1993 is connected with typical meteorological conditions that occur in the south part of Spitsbergen. In the area of Polish Polar Station, four phases of development and degradation of snow cover were distinguished: - intensive blowing out of snow (October - January), - small increase of snow cover thickness (February - March), - considerable increase of snow cover thickness (March - May), - thaws (May, 25th - June, 28th). The thickness of snow cover depended on the altitude and local conditions. Considerable differences were determined in snow thickness at two sites located in small distance from each other (500 m), both close to the seacoast (Fig. 1). Water equivalent of the snow cover at Polish Polar Station (8 m a.s.l.) at the end of winter was only 150 mm, whereas at Fugle site (5 m a.s.l.) it was 2.5 times higher (378 mm). These values were much higher on the glaciers; Hans Glacier in the ELA zone (300 m a.s.l.) - 276 mm and in the accumulation zone (450 m a.s.l.) - 1459 mm; Amundsenisen Plateau (700 m a.s.l.) - 1293 mm.

18

Structural equivalence and stability of some atmospheric air flow models

Brojewski R.

Journal of Technical Physics

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2001

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Vol. 42, no 3

305-325

EN

Two ways of modeling of flows in lower atmosphere forced by stationary flows in upper layers of the atmosphere are presented in the paper. Attention is paid to inequivalence, due to the Coriolis force, of differential models based on 3-D equations of flow of liquid and based on the flow description by means of the stream function. Numerical difficulties of the two ways of solving the flow problem and a way of overcoming them are presented. Structural instability of the models is proved and some of the responsible factors are indicated. Among others are also formal parameters of the model, e.g. the time step of integration.