نتایج جستجو برای: year patterns of monthly environmental and river flow
تعداد نتایج: 24145451 فیلتر نتایج به سال:
In this study, in order to simulate the monthly flow of the Khorramabad River, the time series of this river was decomposed into three levels using the wavelet of Daubechies-3, during the period of 1955-2014. Based on this, it was found that there is a Non-uniform noise that includes two periods of time in this signal, with the October 2008 border which required that the signal be become non-un...
in this paper trends of precipitation and stream flow are analyzed in the atrak river basin in the north khorasan province. normal score linear regression, mann-kendall, and seasonal kendall trend tests were adopted. three precipitation variables and two stream flow variables including total precipitation, maximum daily precipitation, and number of rainy days, mean discharge and peak discharge ...
awareness of the level of river flow and its fluctuations at different times is one of the significant factor to achieve sustainable development for water resource issues. therefore, the present study two hybrid models, wavelet- adaptive neural fuzzy interference system (wanfis) and wavelet- artificial neural network (wann) are used for flow prediction of gamasyab river (nahavand, hamedan, iran...
in this study, we used monthly palmer severity drought index (pdsi) data of national center of oceanic atmospheric administration (noaa) during 1/1950 to 12/2005(56 year). the time and space resolution of data is monthly and 2.5*2.5 degree respectively. therefore 26 pixels located in iran political boundary. a matrix 26*672 carried out that pixels located on rows and month located on column. th...
assigning premium to the insurance contract in iran mostly has based on some old rules have been authorized by government, in such a situation predicting premium by analyzing database and it’s characteristics will be definitely such a big mistake. therefore the most beneficial information one can gathered from these data is the amount of loss happens during one contract to predicting insurance ...
Relationships between satellite-derived water quality variables and river discharges, concentrations and loads of nutrients, organic carbon, and sediments were investigated over a 9-year period (2003–2011) in Pensacola Bay, Florida, USA. These analyses were conducted to better understand which river forcing factors were the primary drivers of estuarine variability in several water quality varia...
INTRODUCTION Hydrologic drought in the sense of deficient river flow is defined as the periods that river flow does not meet the needs of planned programs for system management. Drought is generally considered as periods with insignificant precipitation, soil moisture and water resources for sustaining and supplying the socioeconomic activities of a region. Thus, it is difficult to give a univ...
Instream flow needs (IFN) assessment studies are performed to provide guidelines for stream water management and to assess the impacts of different water projects such as weirs, dams and stream diversions on the available fish habitat. The physical habitat simulation is one of the IFN assessment methods and also a powerful tool in management of river ecosystem that has not become a common metho...
this is an original study on the effect of a polyisobutylene – polydimethylsiloxane (pibpdms) block copolymer modifier used as an interfacial active agent on the dynamics behaviour of single newtonian drops suspended in a polyisobutylene (pib) newtonian matrix. the results were divided in two sections. the first part included the experiments carried out on the non-modified and 2% block cop...
Heavy metal pollution dispersion simulation in rivers and predicting spatial and temporal variations of pollutants can be used to determine the precise place and to schedule water withdrawal time for drinking, agriculture, aquaculture and ecosystem studies. To study the movement of heavy metal pollution through Karoon flow model, MIKE 11 was employed fpr simulation of the flow model of Karoon R...
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