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PL
W pracy podjęto zagadnienie współczesnych zmian zasobów termicznych w sezonie wegetacyjnym w Polsce. Zasoby termiczne określono na podstawie sum nadwyżek średnich dobowych wartości temperatury powietrza powyżej progu 5°C i 10°C (tzw. sumy efektywne temperatury). Wykorzystano dane codzienne z lat 1951-2006 z 10 stacji synoptycznych IMGW z obszaru Polski nizinnej. Posłużono się także serią uśrednioną obszarowo. Określono zakres zmian oraz wieloletnie trendy i fluktuacje zasobów termicznych. Najmniejsze sumy efektywne temperatury w okresie wegetacyjnym pojawiały się w różnych regionach Polski w różnych latach, natomiast skrajnie duże występowały na przeważającym obszarze Polski i koncentrowały się na przełomie XX i XXI wieku. Wykazano istotny wzrost zasobów termicznych oraz przestrzenne zróżnicowanie tempa tego procesu na obszarze Polski. Sumy temperatury powyżej progu 5°C wzrastały w Polsce w tempie 4,0°C na rok, a powyżej 10°C - 2,6°C na rok.
EN
This paper deals with the problem of contemporary changes of thermal resources in the vegetative period in Poland. Thermal resources were specified using the sums of surpluses of mean daily air temperature values above the threshold of 5°C and 10°C (the so called effective sums of temperatures). Daily data from the period 1951-2006 used in the study come from ten synoptic IMGW stations in Polish lowlands. Spatially averaged data series were also used. The range of changes and long-term trends and fluctuations of thermal resources were established. The smallest sums of effective temperatures in the growing season occurred in different regions of Poland and during different periods while extremely high ones appeared in most parts of our country and were concentrated at the turn of the 20th and 21st centuries. The results show a significant increase in thermal resources and spatial differentiation of the rate of this process in Poland. Temperature sums above the threshold of 5°C increased in Poland at a rate of 4.0°C per year and those above the 10°C threshold - at a rate of 2.6°C per year.
PL
Celem badań jest określenie, jak różne sposoby delimitacji nefologicznych dni charakterystycznych wpływają na wyniki analiz. W badaniach posłużono się terminowymi wielkościami zachmurzenia z godziny 06, 12 i 18 UTC z 16 stacji synoptycznych Instytutu Meteorologii i Gospodarki Wodnej z obszaru Polski nizinnej. Są to dane codzienne z lat 1966-2000. Na ich podstawie dwiema metodami obliczono dobowe zachmurzenie: jako średnią i jako sumę terminowych wielkości zachmurzenia. Obliczeń dokonano w odniesieniu do każdej stacji, a następnie zestawiono dwie serie uśrednione obszarowo. Do wyznaczenia dni pogodnych i pochmurnych zastosowano dwa kryteria: kryterium A – dni pogodne Nśr. < 20%, dni pochmurne Nśr. > 80% oraz kryterium B – dni pogodne ΣN⩽4 oktanty, dni pochmurne ΣN≥20 oktantów. Obliczono podstawowe charakterystyki rozkładu tych dni, dokonano oceny trendu ich zmian oraz opisano warunki cyrkulacyjne sprzyjające ich występowaniu. Obliczeń dokonano w odniesieniu do klimatologicznych pór roku i całego roku. Stwierdzono, że zastosowanie różnych metod delimitacji nefologicznych dni charakterystycznych ma wpływ na podstawowe charakterystyki rozkładu oraz na wyniki badań zmienności czasowej tych dni, występowania wartości skrajnych itp. Wyniki analiz dotyczących warunków cyrkulacyjnych towarzyszących występowaniu nefologicznych dni charakterystycznych są na ogół zgodne. Uzyskane wyniki wskazują, że należy podjąć dyskusję dotyczącą wyboru "najlepszej" metody delimitacji nefologicznych dni charakterystycznych i przyjąć tę metodę jako obowiązującą w badaniach klimatologicznych w celu zapewnienia porównywalności i jednoznaczności rezultatów badań.
EN
The purpose of the investigation was to determine in which way different kinds of the characteristic nephological days delimitations influence the research results. The investigations were based on the term cloudiness data from 06, 12 and 18 UTC of every day of 1966-2000 period, coming from sixteen synoptic stations of the Institute of Meteorology and Water Management, localized on the lowlands of Poland. They were used to calculate the daily cloudiness using two methods: as the average value and as the sum of the term cloudiness data. Calculations were done for every station and then two summarized series of data were spatially averaged. Two criteria were used to determine clear and cloudy days in Poland: A criterion – clear days Nśr. < 20%, cloudy days Nśr. > 80%; B criterion – clear days ΣN≤4 octas, cloudy days &Sigma:N≥20 octas. Base characteristics of those days distribution were calculated and the assessment of their trends of changes was also done. Favourable circulation conditions of their occurrence have been established as well. The calculations were made for climatic seasons and the whole year. Particular attention was paid on the differences in the results of characteristic days analysis set on the base of various criteria. It was found that: – basic distribution characteristics (measures of position, dispersion and asymmetry) of nefological characteristic days differ according to the assumed method of their determining, – using different methods of the delimitation of characteristic nefological days influences on research results of these days temporal variability and the occurrence of extreme values and etc., – research results concerning the circulation conditions accompanying the occurrences of characteristic nefological days are generally consistent. The results obtained indicate that it is necessary to discussion concerning the choice of "the best" method of characteristic nefological days delimitation and to assume that methodas the valid one in case of climatic investigations to provide comparability and uniqueness of the research results.
EN
The purpose of the report is to determine trends in thermal conditions in the Polish part of the Tatra Mountains. The study makes use of the data from the weather stations in Zakopane and on Kasprowy Wierch Mt. from the years 1951–2006, and mainly from 1966–2006. Various thermal characteristics were considered. The increase of the rate of upward trend in temperature in the Tatras at the turn of the 21st century, as well as the change of the seasonal distribution of the warming in comparison with the preceding long-term periods, have been documented. In 1966–2006, significant trends in the changes of the mean, maximum and minimum temperatures have been observed in the Tatras in summer (respectively, 0.04, 0.05 and 0.03–0.04 centigrade per annum). Certain symptoms of increase of the thermal continentality have also been observed (increase of the annual amplitude of temperature). Besides, important features of changes in thermal conditions at the turn of the 21st century include an increase in the number of hot days, and even appearance of the very hot days at the foothills of the Tatras, increase of the number of frost days and decrease of the number of ice days in the high mountain part of the Tatras, as well as increase of accumulated heat of the growing season and an increase of daily amplitude of temperature across the entire profile of the Tatras.
PL
Wielkość zachmurzenia nad Polską (poza obszarem gór) opisano średnimi sezonowymi i rocznymi wielkościami zachmurzenia z 48 stacji synoptycznych, obliczając na ich podstawie średnią obszarową wielkość zachmurzenia w kolejnych latach okresu 1951-2000. Określono wielkości anomalne zachmurzenia, stosując podział zbioru oparty na przedziałach kwantylowych. Za anomalne przyjęto te pory roku i lata, w których wielkość zachmurzenia przekraczała kwantyl 90% lub była mniejsza niż określona przez kwantyl 10%. Dokonano analizy pola ciśnienia nad północnym Atlantykiem i Europą na poziomie morza w porach roku i latach o anomalnych wielkościach zachmurzenia nad Polską. Do opisu ciśnienia atmosferycznego użyto średnich sezonowych i rocznych jego wartości, określonych w odniesieniu do punktów węzłowych siatki z obszaru φ 30°-70°N i λ 40°W-60°E. Krok siatki wynosi 5° szerokości i 10° długości geograficznej. Wskazano obszary wystąpienia największych różnic między średnim ciśnieniem w sezonach i latach o anomalnym zachmurzeniu nad Polską i ciśnieniem średnim wieloletnim (1951-2000).
EN
The cloudiness over Poland (except the mountains) was described using seasonal and annual average cloudiness level records from 48 synoptic stations. These were used as bases for calculating the spatial average cloudiness for consecutive years 1951-2000. Anomalous magnitude of cloudiness was determined using the division of series based on quantile interval. It was assumed that the anomalous seasons and years were the ones, in which the cloudiness exceeded the 90 % quantile or was below the value defined by the 10 % quantile. The analysis of the pressure pattern at the sea level for the North Atlantic and Europe in seasons and years with anomalous cloudiness over Poland was carried out. To describe air pressure pattern, its seasonal and yearly average values were used. The values were taken from the nod-points of the grid from the area φ 30°-70°N and λ 40°W-60°E. The grid span was 5° latitude and 10° longitude. The areas of biggest differences between mean pressure in seasons and years with anomalous cloudiness and long-term pressure records (1951-2000) were denoted.
EN
The study determines frequency of clear (N<25%) and overcast (N>75%) days over Poland and favourable barometric situation over Europe and Northern Atlanitic. Additionally the mean pressure partern on cloudless and on total cloudiness days was analysed. In order to determine the amount of cloudiness over Poland (except the mountains) average daily records of sky coverage from 16 synoptic stations were used as bases for calculating the spatial average cloudiness (N) for each day of the 35-year period (1966-2000). For the sake of description of air pressure, its average daily values were used. The values were taken from the nod-points of the grid form the area q 30°-70°N and A 40°W-60°E. The grid step is 5° latitude and 10° longitude. The number of overcast days is 7 times higher than the number of clear days. In the period 1966-2000 clear days accounted for 5.9% of all days which gives the number of 22 days on average in a year (from 1 day in November to 3 days in August and May). Overcast days accounted for 45.4% of all days - 166 days on average in a year (from 8 days in August to 21 days in December). Clear days generally occurred as single days, overcast days as few days sequences. The cloudamount is essentially connected to the atmospheric pressure over Central Europe. In winter, during increased cyclonic circulation, which is reflected in occurrence of trough of low pressure or low pressure centres in baric field over Central Europe, there are favourable conditions for development of big cloudiness over Poland. Similar pressure pattern favours overcast days also in summer, however this occurs rarely and therefore the cloud amount in summer is less. Build-up of high pressure centre over Poland or over neighbouring area with wedge of high pressure over Poland restricts development of cloudiness. Such situation is more frequent in summer, but definitely higher pressure occurs during "clear" and especially "cloudless" highs in winter. Spatial pattern of the highest and the lowest pressure centres in particular months and seasons, on clear as well as on overcast days, is subject only to slight changes or is stable in comparison with mean pattern. The mentioned spatial pattern is different only in case of barometric maximum on clear days during the cold part of the year, when the number of such days is least. The highest pressure is then connected to the high pressure over Poland and not to the high pressure area over Eastern Europe, as it is in the long-term case. During overcast days maximal pressure is sometimes even higher than during clear days, when the high pressure builds-up over Poland. Such situation happens in summer. Therefore it can be stated that the occurrence of clear or overcast days is mainly determined by the large-scale spatial pattern of pressure, which influences the direction of advection over particular area, thus a type of air-masses.
6
Content available remote Wielkość zachmurzenia w Polsce a epoki cyrkulacyjne
EN
The aim of this paper is to determine long-term variation of certain characteristics of mean cloudiness in an annual course in Poland in years 1951-2000. Atmospheric circulation is seen as a determining factor of the cloudiness variation. The annual course of cloudiness is characterized by seasonal values, annual range and by winter and summer deviations from 50-year-means. The analysis performed shows distinctly that years of nephological changes in Poland are also years of boundaries between circulation epochs in different divisions of the second half of the 20th century (half of 60., half of 70. and around year 1983). This is because cloudiness is an element of climate determined mainly by circulation processes acting in a macro-scale. Most of the cloudiness variations in Poland can be explained by direct influence of atmospheric circulation; the west and the meridional components of atmospheric circulation on Central Europe and atmospheric pressure in the centre of this area can explain from 29% (turn of autumn and winter) up to 70% (July) of variability of mean monthly cloudiness values. In autumn and in the average situation in a course of a year the cloudiness depends mainly on the direction of air-mass flow - the meridional component. The role of the pressure values is similar to that of the west component. In other seasons the cloudiness is mainly determined by the atmospheric pressure in the centre of the Central Europe. Among directions of circulation in summer more important is a zonal component, however in spring and in winter - the meridional one. Complexity and seasonal diversification of circulation influence on cloudiness values (essential are: the atmospheric pressure pattern, direction of air-mass flow, frequency of fronts passes and their characters,...) and also often complex character of the circulation epochs make changes in characteristics of cloudiness in a course of a year in each epochs being not unequivocal (similarly as in a situation of air temperature and precipitation).
7
Content available remote Wielkość zachmurzenia w Polsce w drugiej połowie XX wieku
EN
The paper presents the results of the research of the variability of cloudiness in Poland in the second half of 20th century. Average series of cloudiness in the area of Poland (excluding mountains) was analysed. The series was calculated based on data from 48 weather stations of the Institute of Meteorology and Water Management. The direction and rate of changes of cloudiness and its fluctuation were described. Particular attention was paid to anomalous values of cloudiness. Structure of atmospheric circulation, i.e. frequency of circulation types in season and years with anomalous cloudiness was determined.
EN
The paper presents the results of the inquiry into the relations between the dates of the beginning of the meteorological growing season in Poland and the thermal state of the surface of the Northern Atlantic. The variability of this state (the magnitude of the streams of heat flowing from the ocean to the atmosphere, and the distribution of the areas in which the heat transmission is greater or smaller than on the average) conditions the variability of the atmospheric circulation within the reach of influence of the Northern Atlantic, which, in turn, shapes the variability of the beginning of the growing season in Poland. The properties of the distribution of the anomalies of water temperature in the Northern Atlantic were characterised with 10 representative fields, the ,,grids", while the beginning of the growing season was characterised with the sequences of dates (being the numbers of the day in a year corresponding to the instance of passage of the average daily air temperature through the value of 5°C) from 34 weather stations located in Poland (except for the mountainous areas) in the years 1970-1998. The basic method applied in the study is the correlation analysis. The quasi-synchronous relations were analysed (the dates of the beginning of the growing season were correlated with the monthly anomalies of the SST in the particular grids for the same year), as well as the synchronous ones (the shift of the series analysed by one year: the SST from the feth year, the beginning of the growing season - from the k + 1st year). Dependence of the date of the beginning of the growing season on the SST anomalies in some reference grids was established. The dependencies identified are in their majority the asynchronous correlations, and the spatial distribution of the isocorrelates is specific for a definite grid. It was also stated that a more important role in the shaping of the beginning of the growing season is played not so much by the thermal conditions within the particular water areas as by the meridional water temperature gradients between these areas either in a given month or on the average for a period of several months. Attention should be paid to the conformity of the signs of the correlation coefficients for the beginning of the growing season and the SST anomalies appearing a year before, observed synchronously and preceding by 2-3 months the starting instance of the season, and to the distinct spatial and temporal order in the distribution of the SST anomalies, which influence strongly the dates of the beginning of the growing season. The most frequent are the associations with the thermal conditions in the water areas of the Western part of the Northern Atlantic (the Sargasso Sea and the areas to the north of the Gulf Stream delta), with the precedence of the date of the beginning of the growing season amounting to between 11 and 14 months. As time passes, the influence of these water areas fades away and the correlations appear indicating a smaller time precedence (4 to 9 months), concerning the ocean areas located in the moderate latitudes of the central and Eastern parts of the Atlantic Ocean. The article offers, as well, an attempt of a physical interpretation of the results obtained. The paper presents the results of the study aiming at elaboration of the method allowing for the long-term forecasting of the beginning of the growing season for the lowland and upland Poland on the basis of water temperature anomalies of the surface of the Northern Atlantic (their values and spatial distribution). The analysis was carried out with respect to the series shifted by one year: the STT anomalies for the year k, and the beginning of the growing season for the year k + 1. Th study of the nature of relations made it possible to establish that the interdependencies appearing can be described sufficiently precisely with a multivariate linear regression model. In the regression analysis, which was limited - in view of the stability of the regression coefficients - to three independent variables, attention was paid to the relations, which can be physically explained and to those, which simultaneously explain more than 50% of variance of the beginning of the growing season over a broader area, and at least 60% in the zone of the strongest influence. The respective equation has, as well, to satisfy in the zone of appearance of the strongest influence the criterion ofp < 0.001, and the statistical significance of all the three estimates of the directional coefficients of the equation atp < 0.05. Resulting from the multivariate analysis conducted were two prediction equations, fulfilling the prerequisites set. Each of the two equations is proper for a definite part of Poland: 1. Western and Central Poland, 2. Northern and Eastern Poland. These equations contain both the raw data (not normalised monthly averages of the values of the SST anomalies) and the combined variables (like the averages of the values of SST anomalies for the definite water areas from the time periods longer than one month, and the differences of the anomalies between the definite water areas, describing the magnitude of the meridional water temperature gradients, as well as differences of the anomalies for the same water areas between appropriate time intervals). Both equations point out that the primary role from the point of view of the influence exerted by individual ocean areas on the dates of the beginning of the growing season in Poland is played by the heat resources of the Sargasso Sea, which control to a large extent the variations of the thermal conditions over the remaining ocean areas. A simplified verification of the prediction equations was also carried out, having shown that their parameters obtained from the 27-year observation series are stable. In view of the fact that the latest SST anomalies entering the equations date from September, the forecast for the beginning of the growing season in the subsequent year can be formulated already in October.
EN
The aim of the study is to evaluate the correlation between monthly temperature means throughout Poland in the period of 1951-2000 and the pressure and the geostrophic wind in area of the Europe (45-60°N and 10-30°E). The multiple regression equations and correlation coefficients have been calculated (table 1). Indices of circulation (components of the geostrophic wind and pressure) explain over 77 percent of the variance of temperature in January but only 20 percent in August. In winter and spring the significant trends in the changes of pressure, wind components and temperature have been estimated: rise of northern and western components and the resultant geostrophic wind and temperature in December, February, January and February, March and May respectively, and decrease of pressure in April. It was stated, that warming in Poland in the end of the 20th century was mostly controlled by the intensification of western circulation, especially after 1970.
10
EN
The aim of the paper is to evaluate the main patterns of temperature variations in Poland in the second half of the XX-th century. It concerns mainly the answers to 3 questions: 1) at what degree are the averaged values of temperature changed in the period 1951-2000, 2) how are the cyclic components of the observed changes, 3) are there any empirical proofs of the realisation of climate scenarios in which the warming is predicted? The spatially averaged time series of air temperature registered at 51 meteorological stations have been analysed. Several statistical methods have been used both for trends and periodicity identification: analysis of linear regression, the method of rank trend of Mann-Kendall, cumulative deviations, the J. Boryczka method of regression sinusoids, the spectral analysis after Blackmann and Tukey (1958) and singular spectral analysis (SSA) after Vautard (1992). The rise of annual mean temperature in Poland in 50-year period has been estimated as 0.9 centigrade. An increase in temperature intensified significantly after 1980. This warming occurred especially in the spring, in January, February, July and August. The temperature values in spring in 1980. and 1990. were higher then ones estimated in climate scenario (HadCM2 GS) for the middle of XXI-th century. The oscillation of the period of ca 8-year in the annual and December-March monthly temperatures has been found. It explains 31-42 percent of the observed temperature variations. On the other hand - the linear rising trend explains only 9 percent of variation. The climate model HadCM2 GS predicts the rise of annual temperature in Poland in 2050. by 1.4 centigrade from the 1981-2000 mean. However, the coincidence of the simulation with the observed temperature variation in the past is rather weak; differences concern especially the seasonal distribution of temperature changes.
EN
In the report the results of statistical analysis of the mean monthly and annual air temperature series in Poland in the period 1951-2000 have been presented. The calculated means have been based on data from 51 weather stations located at the altitude below 1000 m above the sea level. The mean of the year 2000 was a maximum value of all since 1951 and probably since the end of 18th century. The analysis of order of appearance of rising values using the method of rank trend of Mann--Kendall, has proved an essential positive trend of average annual, March and May temperature values in the period of 1951-2000. This effect has been confirmed by a simple linear trend analysis. The rise of annual mean in 50-year period has been estimated as 0,9 centigrade. The highest May, August and annual average values of temperatures in the period of 1981-2000 proved to be higher than in the period of 1951-2000. In the long-term time series of 1951-2000 a shorter 7-8 year period oscillations around average has been found. In the 80s. and 90s. the significant rise in the mean annual air temperature occurred. Some reasons of climate warming have been discussed including intensification of zonal circulation and rise of insolation in the end of studied 50-year period. The coincidence of climate warming in Poland with global temperature rise has been also stressed
12
Content available remote Oscylacja Północnego Atlantyku a długość okresu wegetacyjnego w Polsce
EN
In the paper are discussed correlations of the beginning and the length of a vegetative period in Poland with of the NAO index. Analysis had been led for 8 stations completely representing the differentiation of climate in Poland during the 60 years period (1931-1990). There has been stated statistically significant correlations of the beginning and the length of a vegetative period with the NAO index, and no correlations the end of a vegetative period and the NAO index. For each station existing correlations are described dy linear equations . They show that there are move exact correlations of the beginning and the length of a vegetative period with an average value of the NAO index, being a difference of the air pressure between Gibraltar and SW Iceland for the period from January to March, than with Hurrell index (Lisboa-Stykkisholmur, December-March). Change of the NAO index about ą2dn changes the duration of a vegetative period on the area of Poland from 21 days (Zakopane) to 46 days (Szczecin) on the average about 31 days. It proves, that the changeability of the length of a vegetative period, which is one the most important ecological factor, is also considerably caused by conditions of circulation. Generally, the influence of the NAO on the beginning and the duration of the vegetative period is decreasing from NW and W edges of Poland in the direction of SE and E.
13
Content available remote Krótkookresowa zmienność temperatury powietrza w Polsce
EN
The aim of the paper is to determine (on the base of the data of the air temperature from 58 meteorological stations): -the periodical changes (from 1 to 30 years) of the air temperature over Poland within a period of 1951-1990 in the climatological seasons and in the year, -identification of causes of the short-term oscillations of the air temperature - pointed out the synchronous cycles of the air temperature, atmospheric circulation and solar activity. The Boryczka's method of 'regression sinusoids' has been used. The spectral analysis shows that over Poland a few cyclical components with meaningful ranges have been observed. These are cycles: 2-, 3-, 6-, 8-, 10-, 14-16-years. Their presence in all chronological progressions and synchronous (the same periods and phases), particularly 8-years cycle, imply thesis, that periodicity is typical feature of temperature field over Poland. The synchronous (concurrence of periods and coincidence of extremums) of 8- and 11-years component of air temperature changes with the solar activity can testify that solar conditions determine these changes. The researches suppose that periodical changes of the air temperature over Poland are conditioned by the corresponding cycles of atmospheric circulation.
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