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In this work a general characteristics of thermal conditions in Kołobrzeg in the years 1976-2005 is presented. The most important part of the paper is the analysis of extreme temperature days (very frosty, frosty, warm and hot) in relation to the types of atmospheric circulation (according to the classification proposed by Osuchowska-Klein 1978). Daily mean and extreme air temperature data for the weather station in Kołobrzeg were the basis of the paper. The obtained results provide strong evidence that the occurrence of days with extreme air temperatures depends mostly on the atmospheric circulation pattern. Particularly high and low air temperatures in Kołobrzeg, in most cases, are not determined by the character (cyclonic or anticyclonic) of atmospheric circulation, but mainly by the direction of air advection. More detailed analysis has revealed that in the winter months (Dec-Feb) the highest frequency of days with sub-zero maximum temperatures is usually associated with the incursion of continental polar air during anticyclonic circulation types. Conversely, maritime air flow from the Atlantic Ocean most often induced by zonal circulation (especially during cyclonic types over Poland) regularly brings warming in winter. In the warm halfyear (Apr-Sep) strong and persistent advection of the air from the southern or eastern sector (in anticyclonic types: E1, E, D2C and cyclonic ones: F and B) is the most important factor determining the occurrence of warm and hot days in Kołobrzeg. The days with tmax ≥ 25oC appear most rarely during the types accompanied by the winds from the western or northern sector.
The study presents the results obtained following the analysis of the so-called Granger causality between daily and monthly temperatures of air and water for the period 1987–2013 carried out for the Noteć river and its two main tributaries: Drawa and Gwda. Granger causality relates to a situation where the data concerning past values of one time series provide important information helping to predict values of another series not included in the information about its past values. The analysis was based on the Granger causality test (of the first order). A causality relationship was established for daily temperature series both for the air-water and water-air directions of influence, which means that forecasting the pattern of river water temperatures from changes to air temperatures can yield better results when done based on data from the previous day. The model forecasting daily water temperature in the Noteć river on the basis of water and air temperatures from the previous day explained 0.07–0.27% of unique variance more than the model that used only water temperature from the previous day. The model forecasting the daily air temperature based on air and water temperatures from the previous day explained 0.3–0.79% of the variance more than the model, which uses only the air temperature from the previous day. For monthly series of water and air temperatures, different configurations of correlations in terms of Granger causality were established: one-way in water-air direction or no correlation, which may result from the river water thermal regime being disturbed by the local impact of anthropogenic factors. In addition, the analysed effect of Granger causality between series of random fluctuations of both temperature models confirmed that causal dependencies occur in both directions. The identification of causal relationships in terms of Granger causality confirms the influence of one data series on the evolution on another data series, and it defines the application potential of study results for the purpose of forecasting the changeability of thermal parameters of river waters. The obtained results may help improve the quality of forecasting changes in water thermal conditions, which is important for managing their environmental condition properly.
The basic features of annual course of air temperature (differentiated between the particular months and seasons) along with air temperature variations during the period between 1950 and 2009 together with the trends of changes are presented. In addition the dependence of air temperature on North Atlantic Oscillation (NAO) is exhibited.
W pracy opisano zmienność średnich miesięcznych opadów w Warszawie i Zakopanem na podstawie danych empirycznych z lat 1965–1990. Do opisu tej zmienności użyto sumy harmonik, bo ona najlepiej uwzględnia sezonowość z wielokrotnymi ekstremami. Udowodniono, że sumy opadów rocznych w Warszawie w wymienionym okresie maleją istotnie. Ma to duże znaczenie dla rolnictwa, gdy temperatura klimatu rośnie. Wyprowadzono wzór na obliczanie średnich opadów miesięcznych od dnia t1 do dnia t2 , przydatny w rolnictwie, przy ogólnej postaci modelu. Sprawdzono użyteczność tego modelu na pełnych miesiącach, bo takie dane empiryczne są do dyspozycji – uzyskano bardzo dobrą zgodność. Wykazano, że ekstrema średnich miesięcznych opadów w odległych miejscowościach Polski nie są przesunięte w czasie, ale mają wyraźnie różne wartości.
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