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Wyszukujesz frazę "diurnal variation" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Seasonal and diurnal variation of outdoor radon (222Rn) concentrations in urban and rural area with reference to meteorological conditions
Autorzy:
Podstawczyńska, A.
Kozak, K.
Pawlak, W.
Mazur, J.
Powiązania:
https://bibliotekanauki.pl/articles/148896.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
outdoor radon (222Rn) concentration
urban climate
seasonal variation
diurnal variation
meteorological parameters
Opis:
The objective of the study was to investigate temporal variability of outdoor radon (222Rn) concentration registered in the center of Łódź (urban station), at Ciosny (rural station) and Kraków (suburban station) in relation to meteorological parameters (i.e. air temperature, temperature vertical gradient, wind speed, soil heat flux, volumetric water content in soil) with special consideration of urban-rural differences. Continuous measurements of 222Rn concentration (at 60 min intervals) were performed at a height of 2 m above the ground using AlphaGUARDŽ PQ2000PRO (ionization chamber) from January 2008 to May 2009. 222Rn levels were characterized by a diurnal cycle with an early morning maximum and a minimum in the afternoon. The well-marked 24 h pattern of radon concentration occurred in summer at anticyclonic weather with cloudless sky, light wind and large diurnal temperature ranges. The urban measurement site was characterized by the lowest atmospheric 222Rn concentration and an urban-rural differences of radon levels increased from winter to summer and during the nighttime periods. The maximum contrasts of 222Rn levels between Łódź and Ciosny, reaching – 30 Bqźm–3, were registered in June and July during the urban heat island (UHI) phenomenon (a positive thermal anomaly of a city if compared to rural area) and strong thermal inversion near the ground in the rural area.
Źródło:
Nukleonika; 2010, 55, 4; 543-547
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diurnal variations in nitrogen, phosphorus and iron compounds in the Southern Baltic Sea
Autorzy:
Sikorowicz, G.
Falkowska, L.
Burska, D.
Dunajska, D.
Pryputniewicz, D.
Magulski, R.
Lewandowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/47649.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
iron
nutrient
Gdansk Deep
nitrogen
density stratification
diurnal variation
Baltic Sea
oxygen condition
phosphorus
Opis:
In order to assess their short-term variability, nutrient concentrations were measured at standard depths at 2 h intervals in the deepest region of the Gdańsk Deep during the first ten days of June 2001. The mean concentrations of nutrients in the euphotic zone were: NN (NO2 −, NO3 −, NH4 +) – 1.93 μmol dm−3, PO4 3− – 0.12 μmol dm−3 and Fetot – 0.11 μmol dm−3. During daylight hours, when the rate of assimilation was fastest, concentrations of nitrogen, phosphorus and iron compounds were very low. The phosphate concentration fell to a minimum (0.03 μmol dm−3) between 04:00 and 10:00 hrs, while total iron dropped to 0.01 μmol dm−3 between 10:00 and 16:00 hrs. Both levels were below the limiting values for phosphorus and iron. At night, concentrations of NO3 − and PO4 3− rose by 25%, those of NH4 + and Fetot by 35%. The mean molar ratios of NN:PO4 3− and Fetot:PO4 3− in the surface layer were subject to significant daily fluctuations. The molar NN:PO4 3− ratio was higher than the optimum value established for the Baltic Sea. Below the halocline, the concentrations of dissolved iron and phosphorus rose as a result of diffusion from sediments in response to changing redox conditions.
Źródło:
Oceanologia; 2005, 47, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustically measured diurnal vertical migration of fish and zooplankton in the Baltic Sea - seasonal variations
Autorzy:
Szczucka, J.
Powiązania:
https://bibliotekanauki.pl/articles/48748.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
zooplankton
fish
temperature
acoustic measurement
marine organism
physical structure
diurnal migration
vertical migration
seasonal variation
water
salinity
Baltic Sea
Opis:
Acoustic measurements were conducted at different seasons in the last five years at a fixed point of the Baltic Sea at a frequency 30 kHzcon currently with temperature and salinity sampling. Echosounding records were used to determine the seasonal and diurnal migration patterns of scattering layers in accordance with thermohaline conditions. Different seasonal patterns of nocturnal aggregations of organisms dependent on the temperature gradient in the thermocline were found. This paper illustrates the diurnal distributions of sound scattering layers and analyses the way they are linked to the physical structure of the water.
Źródło:
Oceanologia; 2000, 42, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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