Variance reduction for trend analysis of hydrochemical data from brackish waters
نویسندگان
چکیده
We propose one parametric and one non-parametric method for detection of monotone trends in nutrient concentrations in brackish waters. Both methods take into account that temporal variation in the quality of such waters can be strongly influenced by mixing of salt and fresh water, thus salinity is used as a classification variable in the trend analysis. With the non-parametric approach, Mann-Kendall statistics are calculated for each salinity level, and the parametric method involves the use of bootstrap estimates of the trend slope in a time series regression model. In both cases, tests for each salinity level are combined in an overall trend test.
منابع مشابه
Multivariate statistical analyzing of chemical parameters of thermal and non-thermal springs of Mahalat area in Iran
In this study multivariate statistical analysis are used to characterize relationships between hydrochemical properties ofthermal and non-thermal springs. Four factors for thermal waters and two for non-thermal springs were extracted basedon factor analysis. In thermal springs, the first factor showed high loading on Ca, Mg, Na and K and this factor wasinterpreted as leaching of cations in the ...
متن کاملSand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio De Janeiro State: hydrological and hydrochemical changes.
The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, s...
متن کاملAssessment of water quality in the Wiśniówka River considering circulation of organic matter
Variation of hydrochemical conditions, with special reference to adequacy of waters as fish habitats, was traced based on selected hydrochemical parameters obtained during the studies conducted from February 2013 till February 2014 year. The results were compared with earlier studies. The sources of organic pollution were identified, and the effect of biogenic substances on the biomass, as well...
متن کاملAnalysis of physiochemical and microbial quality of waters of the Karkheh River in southwestern Iran using multivariate statistical methods
Rapid population growth as well as agricultural and industrial development have increased the contamination of Iranian rivers. This study utilized principal components analysis (PCA) to determine the degree of significance of qualitative parameters of water resources in the Karkheh River in southwestern Iran. Cluster analysis (CA) grouped the monitoring stations based on the water quality data ...
متن کاملHydrogeochemical Evolution of Groundwater Resource in an Arid Region of Southeast Iran (Ravar plain–Kerman province)
This study was carried out in the Ravar plain, a typical arid zone in southeastern Iran, with the objectives of evaluating hydrochemical quality of the groundwater resources and identifying the processes that modify the groundwater composition. Groundwater samples were collected from representative wells spread over the study area. Major cations and anions along with physico-chemical parameters...
متن کامل