نتایج جستجو برای: standardized precipitation index
تعداد نتایج: 516279 فیلتر نتایج به سال:
Drought is one of the most important weather-induced phenomena which may have severe impacts on different areas such as agriculture, economy, energy production, and society. A number of drought indices have been introduced and used in various countries to date. In the current study, four meteorological drought indices including Percent of Normal Precipitation Index (PNPI), Standard Index of Ann...
The presented paper compares forecast of drought indices based on two different models of artificial neural networks. The first model is based on feedforward multilayer perceptron, sANN, and the second one is the integrated neural network model, hANN. The analyzed drought indices are the standardized precipitation index (SPI) and the standardized precipitation evaporation index (SPEI) and were ...
although precipitation is the most important factor which effects rangeland production, but there is little information on the relationship between production and the interactions of climatic factors and specially drought indices. .in this research, the relation between production and climatic factors of rainfall, temperature, evapo- transpiration, and as well as drought indices of standardized...
Defining droughts based on a single variable/index (e.g., precipitation, soil moisture, or runoff) may not be sufficient for reliable risk assessment and decision-making. In this paper, a multivariate, multiindex droughtmodeling approach is proposed using the concept of copulas. The proposed model, named Multivariate Standardized Drought Index (MSDI), probabilist ically combines the Standardize...
Common weaknesses of current drought indexes were analyzed. First, most of the current indexes are not precise enough in detecting the onset, end, and accumulated stress of drought. Second, they do not effectively take into account the aggravating effects of runoff and evapotranspiration, which build up with time. Third, they have a limited usefulness in monitoring ongoing drought because they ...
Drought is a natural and recurring phenomenon which causes water scarcity in various sectors. In comparison with other natural hazards and disasters, drought is more important considering intensity and frequency as well as spatial extent and total damage. In the current research, the Standardized Precipitation Index (SPI) and Standardized Discharge Index (SDI) were used to analyze the tempora...
Drought detecting is a necessary aspect of drought risk management. It is generally performed usingdifferent drought indices that are effectively continuous functions of rainfall and other hydro- meteorologicalvariables. A number of drought indices have been introduced and used in various countries to date. In thecurrent research, four meteorological drought indices including the standardized p...
Drought is a common natural disaster worldwide, with varying durations, severity levels, and spatial extents. This study aimed to model the spatiotemporal variation of meteorological drought events in Gabiley region Somaliland. The utilized primary data collected from station CHIRPS (Climate Hazards Group InfraRed Precipitation Station) develop standardized precipitation index (SPI) at 3-month ...
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