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Potencjał energii słonecznej szacowany dzięki narzędziom GIS

Czernecki B.

Czysta Energia

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2017

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Nr 1-2

40--43

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Convective and non-convective wind gusts in Poland, 2001-2015

Kolendowicz L., Taszarek M., Czernecki B.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2016

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Vol. 4, iss. 2

15--21

EN

The main aim of the article is to present the climatology of the peak wind gust frequency in Poland caused by the impact of both atmospheric circulation and the presence of thunderstorm clouds. Nine meteorological stations for the measurement period of 2001-2015 were taken into account. Only SYNOP reports with a peak wind gust higher or equal to 15 m s-1 in thunderstorm and non-thunderstorm days are considered in this study. The results indicate that the highest threat in terms of frequency and strength of peak wind gusts due to convection occurs in July. In winter, thunderstorms are rare, but if they occur, about 80% of them produce wind gusts exceeding a threshold of 15 m s-1. Peak wind gusts in a non-thunderstorm days are the highest and the most frequent in January, and are at a minimum during summer. Comparing both types, peak wind gusts during days with a thunderstorm were on average stronger than those without an involved convection. This indicated that convection was an important factor in enhancing the strength of a wind gust. The highest value in our base was 34 m s-1, recorded in Kraków on 8th July 2015 within the occurrence of a severe thunderstorm, while the highest value in a day without a thunderstorm was 33 m s-1, recorded in Łódź on 31st January 2002.

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Changes in Spring and Summer Phenology in Poland - Responses of Selected Plant Species to Air Temperature Variations

Jabłońska K., Kwiatkowska-Falińska A., Czernecki B., Walawender J.

Polish Journal of Ecology

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2015

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Vol. 63, nr 3

311--319

EN

Many studies on the changes in the rhythm of nature (animate and inanimate) revealed that plants are good indicators of climate change, because they are responsive to air temperature variations. There is a clear trend towards earlier onset of plant development in Poland, especially for spring phenological events as flowering and leafing. The main objective of this study was to identify phenological tendencies of selected plant indicator species in Poland and to explore the statistical relationship between mean phenological onset date against mean monthly air temperature. Phenological observations of 9 plant species: Corylus avellana L., Tussilago farfara L., Padus avium L., Taraxacum officinale F.H. Wiggers coll., Betula pendula Roth, Syringa vulgaris L., Aesculus hippocastanum L., Robinia pseudoacacia L., Tilia cordata Mill. from 25 locations acquired in the period 1951–1990 were used. The results proved that phenological changes were the reaction of plants to air temperature variations. For spring and summer phenophases, the mean correlation coefficient was negative — higher air temperature was related to earlier onset dates. The advance of spring and summer phenology was estimated at -2.2 days per 1°C. Majority of phenological events were the most significantly correlated with mean monthly air temperature of the preceding months. Phenological trends observed in Poland were mainly negative (73% of analysed stations), significant (22%) but diversified between the selected species. Linear regression analysis of the onset dates against year (including regression coefficient) showed the highest values for Corylus avellana flowering: -0.24 days per year (20% significant) and Betula pendula leaf unfolding: -0.18 days per year (33% significant). Robinia pseudoacacia showed significant advances (72% of negative trends were significant) in a summer season with an average rate of -0.3 days per year. Whereas in case of Tilia cordata no tendencies to advance has been proved.

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The application of probability density function in modeling of wind speed on the Polish Batlic Coast

Czernecki B.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2014

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Vol. 2, Iss. 2

23--33

EN

The aim of the research was to identify the potential for the use of probability density functions (PDF) in modeling of near-surface wind speed. The approaches of Empirical Orthogonal Functions (EOF) and Canonical Correlation Analysis (CCA) are used in combination with 2-parametric Weibull distribution. The downscaling model was built using a diagnosed relationship between sea level pressure (SLP) patterns over Europe and the Northern Atlantic and estimated monthly values of Weibull parameters at 9 stations along the Polish Baltic Coast. The obtained scale (A) and shape (k) parameters make it possible to describe temporal variations of wind fields and their theoretical probability values. This may have further application in the modeling of extreme wind speeds for seasonal forecasting, climate prediction or in historical reconstructions. The model evaluation was done separately for the calibration (1971-2000) and validation periods (2001-2010). The scale parameter was reconstructed reasonably, while there were some problematic issues with the shape parameter, especially in the validation period. The quality of the developed models is generally higher for the winter season, due to larger SLP gradients, whereas the results for the spring and summer seasons were less satisfactory. Despite this, the 99th percentile of theoretical wind speeds are in most cases satisfactory, due to the lesser importance of the shape parameter for typical distributions in the analyzed region.

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Synoptic conditions governing upwelling along the Polish Baltic coast

Bednorz E., Półrolniczak M., Czernecki B.

Oceanologia

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2013

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No. 55 (4)

767--785

EN

The study analyses atmospheric feedback to the occurrence of upwelling along the Polish Baltic coast. Upwelling events were identified on the basis of daily mean sea surface temperature (SST) maps from the period 1982-2010 derived from the NOAA OI SST V2 High Resolution Dataset. Synoptic conditions favourable to the occurrence of upwelling were determined on the basis of the NCEP/NCAR reanalysis data. On average, there are approximately 23 days with upwelling each year along the Polish Baltic coast, which account for approximately 13% of the warm period (April-September). The pressure pattern with an anticyclone centred over Scandinavia and extending over northern Europe induces a north-easterly flow of air along the Polish Baltic coast, which causes upwelling. Such a circulation pattern is accompanied by positive air temperature anomalies. The opposite pressure conditions, during which a trough of low pressure encompasses Scandinavia, cause a westerly flow over the southern part of the Baltic basin, which effectively inhibits upwelling along the Polish Baltic coast.