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Content available Charakterystyka odwilży w Hornsundzie (Spitsbergen)
PL
Celem opracowania jest charakterystyka odwilży i dni odwilżowych w Hornsundzie. Odwilże rozpatrywano podczas 34 sezonów zimowych od 1 grudnia 1982 roku do 30 kwietnia 2016 roku. Pod pojęciem odwilży rozumiano okres co najmniej jednodniowy z temperaturą dobową maksymalną ≥ 0°C, który następuje bezpośrednio po co najmniej dwudniowym okresie mroźnym, czyli z temperaturą dobową maksymalną < 0°C. Dni odwilżowe definiowano jako wszystkie dni z dodatnią temperaturą maksymalną ≥ 0°C w sezonie zimowym, po co najmniej dwóch pierwszych dniach mroźnych po rozpoczęciu tego sezonu. Dokonano oceny zmienności wieloletniej występowania odwilży i dni odwilżowych, określono ich częstość w sezonie zimowym, daty początku, długość ciągów dni, uwarunkowań cyrkulacyjnych ich występowania i warunków meteorologicznych im towarzyszących. Stwierdzono wzrost częstości i długości trwania odwilży oraz przesunięcie zwartego okresu mroźnego z grudnia i stycznia na luty i marzec. Tendencje te są szczególnie widoczne od początku XXI wieku. Występowaniu odwilży sprzyja adwekcja ciepłego powietrza z południa.
EN
Long-term variability in the occurrence of thaw periods can be used as an indicator of climate change in the polar zone due to the snow and ice melting processes associated with them. The study looked at the thaw period and days with thaw parameters at Hornsund and included the long-term variability, frequencies, onset timing, permanence, associated atmospheric circulation and accompanying weather conditions. The study limited itself to looking at thaw periods during the winter season defined by Marsz (2007), which runs from 1 December to 30 April. Thaw was defined as a period of at least one day with a maximum daily temperature equal or greater than zero degrees (TMAX ≥ 0°C), which followed immediately after at least two days of sub-zero temperatures (TMAX < 0°C). Days with a thaw were defined as days with an above-zero daily maximum temperature (TMAX ≥ 0°C) following after at least the first two sub-zero days of a given winter season. The study employed records of daily measurements of air temperature, depth of snow-cover, precipitation totals and wind speed and direction made at the Polish Polar Station in Hornsund during 34 winter seasons from 1 December 1982 to 30 April 2016. During that period, there were on average eight thaw periods per season. The highest number of thaws (15) was recorded in 2015/2016 and the lowest (4) in 1987/1988, 1993/1994 and 2001/2002. The timing of thaw onset varied between seasons, but was most frequent in December (27), followed by January (5) and February. Typical thaws lasted between one and three days in length, but there were many warm spells even exceeding ten days. These longest thaw periods only appeared in Hornsund in 1996, as previously they had never lasted for more than nine days. The longest such warm spell during the study period was recorded between 31 January and 18 February 2014. It was accompanied by a cyclonic situation with air advection from the south-east and south (Niedźwiedź 2016), a peak air temperature of 4.4°C, a wind speed of more than 10 m/s, and a snow cover shrinking rate of 10 cm in four days. Since the beginning of the 21st century, there has been a steady increase in the frequency of days with a winter thaw. In the 2005/2006 season there were 67 such days, while three other seasons also had more than the until-then unheard of 50 days of thaw. The least days with a thaw (6) were recorded in the 1987/1988 season which had the lowest air temperature during a thaw and the lowest number of thaw periods (4), among which there was one three-day spell in January and three isolated days in February, March and April. A total of 18 seasons during the study period, had thaw days in each month, while in the other seasons there would be unbroken monthly or longer periods with freezing temperatures, typically in March, but also in December, January, and February. Winter season weather in Hornsund is primarily determined by atmospheric circulation due to the limited or non-existent solar radiation. The most frequent are cyclonic situations with air advection from the east (Ec peaking in January), north-east (NEc peaking in December) and south-east (SEc peaking in February). April stands out with relatively frequent (more than 8%) anticyclonic situations (Ka and NEa). There are almost no incidences of anticyclonic situations with western or north-western advection (Wa, NWa – less than 1%). Thaws are most likely in the following situations: December – SWc and Sc, January – SWc, Wc and Sc, February – SWa and SWc, March – SWa, Wc ad SWc, and April – SWa, Sc and SWc. In general, the situation favouring a thaw involves air advection either from the south-west regardless of the pressure system, or from the south and west in cyclonic situations.
EN
Investigation of extreme thermal conditions is important from the perspective of global warming. Therefore, this study has been undertaken in order to determine the frequency, timing and spatial extent of extremely cold months in winter time at 60 weather stations across Europe over a sixty-year period from 1951 to 2010. Extremely cold months (ECMs) are defined as months in which the average air temperature is lower than the corresponding multi-annual average by at least 2 standard deviations. Half of all the ECMs occurred in the years 1951-1970 (33 out of 67). The lowest number of ECMs was recorded in the decade 19912000, but since the beginning of the 21st century, their density and territorial extent has started to increase again. The extremely cold months with ECMs of the greatest spatial extent, covering at least one third of the stations (over 20 stations), included: February 1954 (22), February 1956 (36), January 1963 (25), and January 1987 (23 stations).
EN
The performance of RegCM4 for seasonal-scale simulation of winter circulation and associated precipitation over the Western Himalayas (WH) is examined. The model simulates the circulation features and precipitation in three distinct precipitation years reasonably well. It is found that the RMSE decreases and correlation coefficient increases in the precipitation simulations with the increase of model horizontal resolutions. The ETS and POD for the simulated precipitation also indicate that the performance of model is better at 30 km resolution than at 60 and 90 km resolutions. This improvement comes due to better representation of orography in the high-resolution model in which sharp orography gradient in the domain plays an important role in wintertime precipitation processes. A comparison of model-simulated precipitation with observed precipitation at 17 station locations has been carried out. Overall, the results suggest that 30 km model produced better skill in simulating the precipitation over the WH and this model is a useful tool for further regional downscaling studies.
PL
Przedstawiono wyniki analizy intensywności parowania wody z powierzchni basenów kąpielowych i przepływu ciepła między powierzchnią wody i otaczającym powietrzem oraz miedzy powietrzem a otaczającymi przegrodami – szczególnie przeszklonymi, biorąc pod uwagę sposób nawiewu powietrza do hali basenu krytego. Okazuje się, że nieodpowiednie zaprojektowanie rozdziału powietrza w hali basenu może spowodować istotne zwiększenie odparowania wody z basenu do powietrza oraz zwiększenie strat ciepła obiektu przez przegrody przeszklone w okresie zimowym.
EN
Results of an analysis are presented concerning intensity of water evaporation from surfaces of swimming pools and between the surface and surrounding air. The results include also the same phenomena between the air and surrounding barriers, especially glass barriers, taking into account the method of ventilation of the indoor swimming pool. It is shown that inadequate ventilation design may cause essential increase of water evaporation from the pool surface into the air and increase of heat losses of an object through the glass barriers in winter season.
EN
The PM2.5/PM 10 ratio expresses the anthropogenic share in atmospheric dust. Very high values of this ratio, i.e. high contribution of PM2.5 to PM 10, have occurred recently in atmospheric air within Europcan industrialized areas. The paper compiles results of three year pair wise measuring of concentrations of PM2.5 and PM2.5-10 and compares shares of PM2.5 in P'M 10 al three urban background sites in Upper Silesia Poland downs of Zabrze, Katowice and Częstochowa). At all the three locations, the PM2.5/PMI0 ratio of daily concentrations of dust only occasionally differed considerably from the PM2.5/PM10 ratios for the seasonal and yearly concentrations that, in turn, did not differ from the PM2.5/PMI0 ratios at urban sites in Europe.
PL
Stosunek PM2.5/PMI0 jest wskaźnikiem udziału pyłu pochodzenia antropogenicznego w zanieczyszczonym pyłem powietrzu na danym obszarze. Przeprowadzone w ostatnich lalach badania w terenach silnie zurbanizowanych pokazują bardzo wysoki udział PM2,5 w I'M 10. Celem pracy jest zestawienie otrzymanych na przestrzeni trzech lat wyników jednoczesnych pomiarów PM2.5 i PM2.5-10 i porównanie udziałów PM2.5 w PM10 w trzech różnych punktach charakterystycznych dla tła miejskiego na Górnym Śląsku (Zabrze, Katowice, Częstochowa). Wyniki pomiarów prowadzonych w Częstochowie, Zabrzu i Katowicach są reprezentatywne dla obszarów tła miejskiego aglomeracji. W okresie badań stosunek PM2.5/PM1O w badanych miejscach niekiedy przyjmował pojedyncze wartości znacznie odbiegające od średnich, generalnie jednak wartości średnie nie odbiegają od średniego notowanego stosunku tych frakcji w aglomeracjach miejskich Europy.
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