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111.
A. Szczucińska 《Geochemistry International》2017,55(12):1164-1170
Hydrogeochemical background determined for an investigated environment, defines characteristic range of its hydrochemical characteristics. This allows to observe the temporal changes of the chemical water properties taking place in the studied environments, such as due to human impact. The paper presents the results of study on the present-day hydrogeochemical background in the Lubuskie Lakeland, the region repeatedly covered by the ice sheets during the Pleistocene and little affected by anthropogenic impact. The hydrogeochemical background was established on a basis of physicochemical analyses of spring waters sampled every 3 months between November 2011 and October 2013 from 20 springs. Present-day hydrogeochemical background was assumed to be represented by values ranging between 16 and 84 percentiles. The ranges of hydrogeochemical background for the studied ions on the Lubuskie Lakeland, were in the lower range of the background considered for useful waters in Poland. The obtained results indicated that the studied spring waters were poorly diversified in terms of composition of main cations and anions, as well as electrical conductivity and total water hardness. However, large variability was observed for Fetot, Mn2+ and NO3?. Moreover, NO3? and SO42? were noted in some cases to be in excess of national hydrogeochemical background values. 相似文献
112.
Sea surface temperature (SST) from a near real-time data set produced from satellites data has been assimilated into a coupled
ice–ocean forecasting model (Canadian East Coast Ocean Model) using an efficient data assimilation method. The method is based
on an optimal interpolation scheme by which SST is melded into the model through the adjustment of surface heat flux. The
magnitude and space–time variation of the adjustment depend on the depth of heat diffusion into the water column in response
to changes in surface flux, the correlation time scale of the data, and model and data errors. The diffusion depth is scaled
by the eddy diffusivity for temperature. The ratio of the model and data errors is treated as an adjustable parameter. To
evaluate the quality of the assimilation, the results from the model with and without assimilation are compared to independent
ship data from the Atlantic Zone Monitoring Program and the World Ocean Circulation Experiment. It is shown that the assimilation
has a significant impact on the modeled SST, reducing the root mean square difference (RMSD) between the model SST and the
ship SST by 0.63°C or 37%. The RMSD of the assimilated SST is smaller than that of the satellite SST by 0.23°C. This suggests
that model simulations or predictions with data assimilation can provide the best estimate of the true SST. A sensitivity
study is performed to examine the change of the model RMSD with the adjustable parameter in the assimilation equation. The
results show that there is an optimal value of the parameter and the model SST is not very sensitive to the parameter. 相似文献
113.
New marine ΔR values for Arctic Canada 总被引:1,自引:0,他引:1
Roy D. Coulthard Mark F.A. Furze Anna J. Pieńkowski F. Chantel Nixon John H. England 《Quaternary Geochronology》2010,5(4):419-434
For more than four decades, the reporting of 14C dates on marine molluscs from Arctic Canada has been notable for the lack of consistently applied marine reservoir corrections. We propose that the common approach of reporting Canadian Arctic marine 14C dates using presumed time-invariant reservoir corrections be abandoned in favour of calibration of 14C dates, using the current standard protocol. This approach best facilitates inter- and intra-regional correlation, and correlation with other geochronometers. In order to enable the consistent calibration of marine 14C dates from Arctic Canada, we analysed a 14C database of 108 marine mollusc samples collected live between 1894 and 1956, and determined regional reservoir offset values (ΔR) for eight oceanographically distinct regions. The following new ΔR values should be used for 14C calibration: NW Canadian Arctic Archipelago, 335 ± 85 yrs; Foxe Basin, 310 ± 90 yrs; NE Baffin Island, 220 ± 20 yrs; SE Baffin Island, 150 ± 60 yrs; Hudson Strait, 65 ± 60 yrs; Ungava Bay, 145 ± 95 yrs; Hudson Bay, 110 ± 65 yrs; and James Bay, 365 ± 115 yrs. 相似文献
114.
115.
Comparison of Two Nonstationary Flood Frequency Analysis Methods within the Context of the Variable Regime in the Representative Polish Rivers 总被引:2,自引:0,他引:2
Witold G. Strupczewski Krzysztof Kochanek Ewa Bogdanowicz Iwona Markiewicz Wojciech Feluch 《Acta Geophysica》2016,64(1):206-236
Changes in river flow regime resulted in a surge in the number of methods of non-stationary flood frequency analysis. Common assumption is the time-invariant distribution function with time-dependent location and scale parameters while the shape parameters are time-invariant. Here, instead of location and scale parameters of the distribution, the mean and standard deviation are used. We analyse the accuracy of the two methods in respect to estimation of time-dependent first two moments, time-invariant skewness and time-dependent upper quantiles. The method of maximum likelihood (ML) with time covariate is confronted with the Two Stage (TS) one (combining Weighted Least Squares and L-moments techniques). Comparison is made by Monte Carlo simulations. Assuming parent distribution which ensures the asymptotic superiority of ML method, the Generalized Extreme Value distribution with various values of linearly changing in time first two moments, constant skewness, and various time-series lengths are considered. Analysis of results indicates the superiority of TS methods in all analyzed aspects. Moreover, the estimates from TS method are more resistant to probability distribution choice, as demonstrated by Polish rivers’ case studies. 相似文献
116.
Dinh Chau Nguyen Phon Le Khanh Paweł Jodłowski Jadwiga Pieczonka Adam Piestrzyński Hao Duong Van Jakub Nowak 《Acta Geophysica》2016,64(6):2305-2321
The field radiometric and laboratory measurements were performed at the Sin Quyen copper deposit in North Vietnam. The field gamma-ray spectrometry indicated the concentration of uranium ranging from 5.5 to 87 ppm, thorium from 5.6 to 33.2 ppm, and potassium from 0.3 to 4.7%. The measured dose rates ranged from 115 to 582 nGy/h, the highest doses being at the copper ore. Concentrations in the solid samples were in the range of 20–1700 Bq/kg for uranium, 20–92.7 Bq/kg for thorium, and 7–1345 Bq/kg for potassium. The calculated doses were from 22 to 896 nGy/h; both measured and calculated dose rates are mostly related to uranium. Concentrations of radium in water samples were below 0.17 Bq/L. Uranium in water samples was significantly higher than the hydrogeological background; the maximum of 13 Bq/L was at the waste zone pool, but neither radium nor uranium were present in tap water. Radon concentration in the dwelling air was from 42 to 278 Bq/m3 for 222Rn and from 8 to 193 Bq/m3 for 220Rn. The estimated committed dose rates were principally related to 222Rn concentration and ranged from 1.1 to 8.1 mSv/y. 相似文献
117.
In 2011, a geophysical survey was carried out in the surroundings of the Jagiellonian University in Cracow, using a Very Low Frequency method. The measurements were designed to determine the reason of frequent flooding of the lowest level of the building. The main objective of the study was to find out from where and in which way the rainwater seeps into the building and how this problem can be solved in the least invasive manner. The aim of geophysical methods was also to provide necessary information that will enable the construction of a hydro-geological model of the local environment. The interpretation revealed the presence of a sandy gutter surrounded by impermeable clay. There is a big resistivity contrast between those layers. Their location and approximate dimensions were determined. 相似文献
118.
AbstractThe combined analysis of precipitation and water scarcity was done with the use of the Standardized Precipitation Index (SPI) and the Standardized Runoff Index (SRI), developed as a monthly, two-variable SPI-SRI indicator to identify different classes of hydrometeorological conditions. Stochastic analysis of a long-term time series (1966–2005) of monthly SPI-SRI indicator values was performed using a first-order Markov chain model. This provided characteristics of regional features of drought formation, evolution and persistence, as well as tools for statistical long-term drought hazard prediction. The study was carried out on two subbasins of the Odra River (Poland) of different orography and land use: the mountainous Nysa K?odzka basin and the lowland, agricultural Prosna basin. Classification obtained with the SPI-SRI indicator was compared with the output from the NIZOWKA model that provided identification of hydrological drought events including drought duration and deficit volume. Severe and long-duration droughts corresponded to SPI-SRI Class 3 (dry meteorological and dry hydrological), while severe but short-term droughts (lasting less than 30 days) corresponded to SPI-SRI Class 4 (wet meteorological and dry hydrological). The results confirm that, in Poland, meteorologically dry conditions often shift to hydrologically dry conditions within the same month, droughts rarely last longer than 2 months and two separate drought events can be observed within the same year. 相似文献
119.
An analysis of linear relationships between the ground-level components of the Earth’s magnetic field measured at different sites is a relatively new topic compared to the analysis of data at a single location. The data collected by the INTERMAGNET observation network provide perfect set of data to which this analysis can be used. An important tool in this analysis may be developing a method of determination of the impulse response for linear systems in the time domain. An advantage of calculations in the time domain over the generally known and applied methods in the frequency domain is the possibility of determining prediction of output signals. By that, simultaneously with the analysis of linear relationships, a tool for recovering missing records in incomplete observation data is obtained. Filling-in the missing data may increase interest and possibility of using the observational data by researchers experimenting with the analysis in the frequency domain where gaps in data records are a significant limitation. 相似文献
120.
Witold Prószyński 《Journal of Geodesy》2013,87(1):89-99
The paper presents an approach to internal reliability analysis of observation systems known as Errors-in-Variables (EIV) models with parameters estimated by the method of least squares. Such problems are routinely treated by total least squares adjustment, or orthogonal regression. To create a suitable environment for derivations in the analysis, a general nonlinear form of such EIV models is assumed, based on a traditional adjustment method of condition equations with unknowns, also known as the Gauss–Helmert model. However, in order to apply the method of reliability analysis based on the approach to response assessment in systems with correlated observations, presented in the earlier work of this author, it was necessary to confine the considerations to a quasi-linear form of the Gauss–Helmert model, representing quasi-linear EIV models. This made it possible to obtain a linear disturbance/response relationship needed in that approach. Several specific cases of quasi-linear EIV models are discussed. The derived formulas are consistent with those already functioning for standard least squares adjustment problems. The analysis shows that, as could be expected, the average level of response-based reliability for such EIV models under investigation is lower than that for the corresponding standard linear models. For EIV models with homoscedastic and uncorrelated observations, the relationship between the average reliability indices for the independent and the dependent variables is formulated for multiple regression and coordinate transformations. Numerical examples for these two applications are provided to illustrate this analysis. 相似文献