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Dive into the research topics where Marek Kejna is active.

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Featured researches published by Marek Kejna.


Antarctic Science | 2015

Short-term mass changes and retreat of the Ecology and Sphinx glacier system, King George Island, Antarctic Peninsula

Ireneusz Sobota; Marek Kejna; Andrzej Araźny

Abstract This study investigated the mass balance, melting, near-surface ice thermal structure and meteorological conditions of the Ecology and Sphinx glacier system (ESGS), located on King George Island, Antarctic Peninsula. The study also analysed the role of climate change in glacial retreat of the ESGS in the long (1979–2012) and short term, with a particular focus on the impact on the 2012–13 mass balance of the ESGS. In 2012–13, the glaciers had a mean annual net mass balance of +17.8 cm w.e., but over the long term the glaciers have been receding in this region. The area loss of the ESGS between 1979 and 2012 amounted to 41%. This investigation of mass balance is especially important as it offers one of only a few records available on King George Island. The mean near-surface ice temperature (February to June 2012) for the Ecology and Sphinx glaciers was -0.3°C and -1.0°C at 10 m depth, respectively. From 1948–2012, the air temperature on King George Island increased by 1.2°C (0.19°C per decade).


Bulletin of Geography: Physical Geography Series | 2009

DAILY MINIMUM AND MAXIMUM AIR TEMPERATURE IN POLAND IN THE YEARS 1951–2005

Marek Kejna; Andrzej Araźny; Rafał Maszewski; Rajmund Przybylak; Joanna Uscka-Kowalkowska; Zsuzsanna Vízi

In this study grid data of daily maximum and minimum air temperatures taken from the NCEP/NCAR reanalysis for the territory of Poland for the years 1951–2005 have been used as a basis for an analysis of the spatial distribution of daily maximum and minimum air temperature, the frequency of characteristic days and the variability of these parameters in the period analysed. The results obtained were then compared to the variability in atmospheric circulation in Europe, described by the North Atlantic Oscillation (NAO) index.


Bulletin of Geography: Physical Geography Series | 2013

GROUND TEMPERATURE AT THE HENRYK ARCTOWSKI STATION (KING GEORGE ISLAND, ANTARCTIC) – CASE STUDY FROM THE PERIOD JANUARY 2012 TO FEBRUARY 2013

Andrzej Araźny; Marek Kejna; Ireneusz Sobota

Abstract The article presents the results of measurements of ground temperature in the context of general meteorological conditions at the Henryk Arctowski Station (King George Island, South Shetland Islands, Antarctic) from the period of 20 January 2013 to 22 February 2013. The measurements were taken using a Vantage Pro+ automatic weather station and the thermal conditions of the ground were measured by means of a HOBO automatic data logger. The variability of ground temperature was analysed in an annual and diurnal cycle. A clear recurrent diurnal pattern was observed in the summer season, resulting from more favourable insolation conditions in that part of the year. In the winter, on the other hand, no major differences in the diurnal cycle of ground temperature were found, particularly with a dense snow cover.


Annals of Warsaw University of Life Sciences, Land Reclamation | 2015

Comparison of the predicted insulation of clothing in Toruń and Koniczynka in the years 1998–2012*

Andrzej Araźny; Joanna Uscka-Kowalkowska; Marek Kejna

Abstract: Comparison of the predicted insulation of clothing in Toruń and Koniczynka in the years 1998–2012. This paper compares the predicted insulation of clothing (Iclp) in Toruń and Koniczynka, presented using a scale of evaluation of thermal environment proposed by B. Krawczyk (2000). The annual mean value of predicted insulation of clothing in urban areas of Toruń was equal to 1.0 clo, which was 0.1 less than in the agricultural area of Koniczynka. The influence of atmospheric circulation on the Iclp index was also analysed. The study used the circulation types as classified by Niedźwiedź (1981) in the Catalogue of atmospheric circulation for the Bydgoszcz-Toruń region (Przybylak and Maszewski 2009, 2013). The frequency of occurrence of individual circulation types was examined along with their influence on the predicted insulation of clothing in different seasons of the year and in an annual course. During the year, the highest mean value of Iclp (1.4 clo in Koniczynka) corresponded to cyclonic situations with northerly advection, whereas the lowest value (0.8 clo in Toruń and Koniczynka) was observed for the anticyclonic wedge.


Bulletin of Geography: Physical Geography Series | 2012

The Influence of Cloudiness and Synoptic Situations on the Solar Radiation Balance in the Area of Kaffiøyra (Nw Spitsbergen) in the Summer Seasons 2010 and 2011

Marek Kejna; Rajmund Przybylak; Andrzej Araźny

Abstract This article describes the influence of cloudiness and synoptic situations on individual components of the radiation balance such as: global solar radiation; surface-reflected radiation; longwave terrestrial and atmospheric radiation, and the long- and shortwave balance of two types of ground cover typical to Spitsbergen (the Kaffiøyra region), i.e. morainal and glacial. The research was carried out in the summer seasons of 2010 and 2011, using a Kipp & Zonen CNR4 net radiometer. A substantial influence of the presence of clouds on the individual components of the radiation balance was observed. The type of air masses related to specific synoptic situations was also found to affect the incoming and outgoing solar radiation, as well as its losses.


Bulletin of Geography: Physical Geography Series | 2016

Ground thermal regime on the Kaffiøyra Plain (NW Spitsbergen) in the period from 1 September 2012 to 31 August 2014

Andrzej Araźny; Rajmund Przybylak; Marek Kejna

The article presents the results of ground temperature measurements taken at 1 cm to 100 cm below ground level on the Kaffioyra Plain (NW Spitsbergen) from 1 September 2012 to 31 August 2014. Observations of thermal conditions were carried out at three sites located in characteristic Polar ecotopes: on a beach, in tundra and on a moraine. The results of ground temperature measurements for the Kaffioyra Plain were compared to the observations of weather conditions at the nearby meteorological station in Ny-Alesund. The variability of ground temperature was analysed in annual, seasonal and diurnal courses. These reflected the prevailing meteorological conditions at the time. Substantial differences in the ground thermal conditions were found between the ecotopes, which was due to the morphological diversity of the ground, its moisture content, vegetation and snow cover, as well as the depth of the permafrost.


Bulletin of Geography: Physical Geography Series | 2014

SPATIAL DIFFERENTIATION OF GLOBAL SOLAR RADIATION IN TORUŃ AND ITS SUBURBAN AREA (CENTRAL POLAND) IN 2012

Marek Kejna; Joanna Uscka-Kowalkowska; Andrzej Araźny; Mieczysław Kunz; Rafał Maszewski; Rajmund Przybylak

Abstract : This article investigates the spatial distribution of global solar radiation (K↓) in Toruń and its suburbs, observed in 2012. Measurements were taken at 12 points (7 within the city and 5 in the suburban area) using CNR4 net radiometers and automatic weather stations (Vantage Pro+). At all locations, the diurnal and annual courses of K↓ were typically related to the Earth’s rotational movement and changes in the sun’s declination over the year, and disturbed by clouds and atmospheric phenomena that enhance the extinction of solar radiation. A substantial spatial diversity of K↓ was observed in Toruń and its suburbs. The annual sum of K↓ at several urban locations accounted for over 70% of the solar radiation in the open space outside the city. The amount of incoming solar radiation in the urban area was more restricted in winter (<50%) than in summer (approx. 70%). The diurnal courses of K↓ were heavily disturbed by local obstacles which cast shadows (causing a considerable decrease of K↓), but there were instances of increases in K↓ (122%) augmented by radiation reflected from roofs, walls and windows surrounding the measurement point. The spatial diversity of K↓ in the urban area is heterogeneous, due to local meteorological conditions (cloudiness, fog, smog and airborne dust) and the obscuring of the horizon.


Polish Polar Research | 1999

Air temperature on King George Island, South Shetland Islands, Antarctica

Marek Kejna


International Journal of Climatology | 2014

Spatial distribution of air temperature on Svalbard during 1 year with campaign measurements

Rajmund Przybylak; Andrzej Araźny; Øyvind Nordli; Roman Finkelnburg; Marek Kejna; Tomasz Budzik; Krzysztof Migała; Sebastian Sikora; Dariusz Puczko; Krzysztof Rymer; Grzegorz Rachlewicz


Polish Polar Research | 2013

Climatic change on King George Island in the years 1948-2011

Marek Kejna; Andrzej Araźny; Ireneusz Sobota

Collaboration


Dive into the Marek Kejna's collaboration.

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Rajmund Przybylak

Nicolaus Copernicus University in Toruń

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Andrzej Araźny

Nicolaus Copernicus University in Toruń

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Joanna Uscka-Kowalkowska

Nicolaus Copernicus University in Toruń

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Rafał Maszewski

Nicolaus Copernicus University in Toruń

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Kazimierz Marciniak

Nicolaus Copernicus University in Toruń

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Mieczysław Kunz

Nicolaus Copernicus University in Toruń

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Ireneusz Sobota

Nicolaus Copernicus University in Toruń

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Zsuzsanna Vízi

Nicolaus Copernicus University in Toruń

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Gabriel Wójcik

Nicolaus Copernicus University in Toruń

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