Wyniki wyszukiwania - Biblioteka Nauki

1

Diurnal variability of water vapour in the Baltic Sea region according to NCEP-CFSR and BaltAn65+ reanalyses

100%

Jakobsons E. , Keernik H. , Luhamaa A. , Ohvril H.

Oceanologia

|

2014

|

tom No. 56 (2)

191--204

EN

Diurnal variations in water vapour in the Baltic Sea region are examined using BaltAn65+ and NCEP-CFSR reanalyses of summer (JJA) data for the period 1979-2005. A systematic difference between precipitable water (PW) diurnal variability above the land and the water is revealed. Above the land, PW diurnal variability has minimal values at 00 and 06 UTC, as in previous studies, whereas above the water, the minima are at 12 and 18 UTC. Diurnal variability in the vertical humidity profile is controlled by turbulent mixing and the diurnal behaviour of sea breezes. The impacts and proportions of diurnal variability of humidity are evaluated at different vertical levels.

2

Diurnal variability of water vapour in the Baltic Sea region according to NCEP-CFSR and BaltAn65plus reanalyses

86%

Jakobson E. , Keernik H. , Luhamaa A. , Ohvril H.

Oceanologia

|

2014

|

tom 56

|

nr 2

3

Diurnal variations of the basic physico-chemical characteristics of a small urban river – the Sokolowka in Lodz – a case study

86%

Bartnik A. , Tomalski P.

Acta Scientiarum Polonorum. Formatio Circumiectus

|

2018

|

tom 17

|

nr 3

EN

The main purpose of the paper was to identify day-and-night variations of the selected physico-chemical water characteristics (discharge, electrical conductivity, temperature, pH and dissolved oxygen) of a small urban river that had been heavily transformed by human activity (Sokołówka river catchment with the area of 7.71 km²). The data came from measurements conducted in the period between 4 October 2011 and 3 October 2012, using the YSI 6920 V2 (multi-parameter probe) and ISCO 2050 (automatic current meter), in 15- and 10-minute intervals, respectively. The research has proven the existence of rhythms of diurnal and seasonal variability to the selected water characteristics. The variability of the hourly values of the tested characteristics in particular days depends to a large extent on the value of the analysed feature itself. The variability coefficients of discharge and conductivity increase with the increase in the values thereof. For dissolved oxygen, pH, and water temperature, the variability coefficients decrease with the increase in the values thereof. In the case of water pH, its conductivity, and temperature, the correlations between the given feature and its variability observed at different times of day are not linear, but they run along loops of varying curvature. The average day-and-night variability of the Sokołówka river’s SEC and pH was significantly changed as a result of human impact. The maximum readings of the conductivity and the pH shifted to the morning hours, with no change to the minimum readings.

PL

Celem prezentowanego opracowania była identyfikacja dobowej zmienności wybranych cech fizykochemicznych wody (natężenie przepływu, konduktywność temperatura i odczyn wody oraz stężenie rozpuszczonego w wodzie tlenu) przekształconego przez człowieka cieku miejskiego (zlewnia Sokołówki o powierzchni 7,71 km²). Wykorzystano wyniki pomiarów prowadzonych od 4 X 2011 r. do 3 X 2012 r. przy pomocy wieloparametrycznej sondy pomiarowej YSI 6920 V2 oraz przepływomierza ISCO 2150 zapisujących wyniki z krokiem odpowiednio: 15- i 10-minutowym. Badania udowodniły istnienie rytmów zmienności dobowej i sezonowej. Zmienność godzinowych wartości badanych charakterystyk w poszczególnych dniach w znacznym stopniu zależy od wielkości analizowanej cechy. W przypadku natężenia przepływu i przewodnictwa elektrolitycznego wody zmienność ta (wyrażona współczynnikiem zmienności) rośnie wraz z ich wzrostem, a w przypadku tlenu rozpuszczonego, odczynu wody i temperatury – spada. Dla odczynu wody, jej konduktywności i temperatury obserwowane o różnych godzinach zależności pomiędzy daną wielkością a jej zmiennością nie są liniowe lecz tworzą pętle o różnym kształcie. Przeciętna dobowa zmienność przewodnictwa elektrolitycznego właściwego oraz odczynu wód Sokołówki uległa zmianom pod wpływem działalności człowieka. Maksima konduktywności i odczynu wody przesunęły się na godziny poranne przy braku zmian terminów występowania minimów.

4

Quasi Real-Time X-Ray Fluorescence Spectrometer in Source Apportionment of Particulate Matter in a Typical Suburban Area

86%

Mach T. , Rybak J. , Bihałowicz J. , Rogula-Kozłowska W.

Journal of Ecological Engineering

|

2022

|

tom Vol. 23, nr 10

89--97

EN

The article studies the data from a weekly campaign devoted to the study of the elemental composition of PM10 in a selected receptor, in a suburban area (Mazowieckie Voivodeship). The sampling point was located at the intersection of main roads and in the vicinity of a typical single-family housing, not far from the electrified Warsaw-Białystok railway line and a small heating plant. The research was carried out in the summer season, in order to minimize the impact of municipal emissions on the concentrations and elemental composition of PM10. A Horiba PX-375 X-ray fluorescence spectrometer was used to measure the one-hour concentrations of elements related to PM10. On the basis of the obtained results, the enrichment factors for PM10 in the analyzed elements (EF) were calculated and the principal components analysis (PCA) was performed. It was found that although the elemental composition of PM10 in all tested time intervals was noticeably influenced by the emissions from transport, the municipal emissions had a significant impact on the elemental composition, especially those related to coal combustion, and thus the concentration of PM10 during the study period. It seems that the possibility of observing the influence of all relevant sources on the composition and concentration of PM10 was possible owing to the use of hourly-averaged measurements of the elemental composition of PM10. In the case of daily averaged measurements, in a receptor with such PM10 elemental profile, it would be impossible to determine the periods, in which specific – qualitatively completely different – emission sources dominate.

5

A contribution to the knowledge of Arctic zooplankton diurnal variability [Kongsfjorden, Svalbard]

72%

Walkusz W. , Kwasniewski S. , Dmoch K. , Beszczynska-Moller A.

Polish Polar Research

|

2007

|

tom 28

|

nr 1

EN

Zooplankton was investigated at fixed site in 24 hours in Kongsfjorden, a glacial fjord situated on the west coast of Spitsbergen (Svalbard) (79°N, 12°E), in order to unveil the level of diurnal variability in community composition and abundance. Parallel to zooplankton study water temperature and salinity were measured while information on local tides and winds was obtained from external sources. Observed changes did not exceed the range of variability regarded intrinsic, resulting from the nature of plankton. Because of this low variability we are of the opinion that the data presented can be regarded a valid measure of the natural heterogeneity of zooplankton communities in hydrologically dynamic Arctic coastal waters in summer. The observed changes in zooplankton were primarily induced by the complex dynamics of the fjord's water masses. In spite of importance of tidal forcing, the variability in zooplankton did not demonstrate similar temporal fluctuations due to modification of the water movement by other irregular forces (local wind). Also, we have not found any indication of diel vertical migration in coastal water in the Arctic under the condition of midnight sun.