نتایج جستجو برای: drought index
تعداد نتایج: 424034 فیلتر نتایج به سال:
drought stress is the most important factor that reduces yield in crops including chickpea and causes some changes in seed composition. this study was performed in order to evaluate the effects of drought stress and starter nitrogen fertilizer on four cultivars of chickpea. experiment was performed in a split-factorial using randomized complete block design with three replications. drought stre...
drought is a natural hazard that has significant impact on economic, agricultural, environmental, and social aspects. in the present study details analysis of rainfall data has been carried out for the years 1981-2011. standard precipitation index (spi) has been used to evaluate the precipitation deficit in the karun watershed of iran. the results indicated that 1981-82,82-83,83-84,84-85,88-89,...
The Standardized Precipitation Index (SPI) has become a popular measure of drought across the globe. In this study, Standardized Precipitation Index (SPI) was used in annual period of time to survey on drought. Also, in order to zonation frequency of drought, geographic information system (GIS) software and Kriging method used for extracting dry areas. The zoning maps show most severe drought i...
in this article, new index, the optimized synthetized drought index (osdi), is suggested for real-time monitoring of this phenomenon in areas with heterogeneous land covers. the precipitation, one of the important factors in drought, measured by ground stations and improved bytrmm satellite data. each of the three normalized moisture indices, including normalized difference vegetation index (nd...
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 major problematic phenomenon mostly for semi-arid areas of Iran. During drought periods, reduction in vegetation levels causes such problems as soil erosion, surface runoff, flood risk, etc. Therefore, the assessment of drought effects on plant covers is the most important issue. This research was conducted in 2015 using the extracted vegetation indices from Moderate Resolution Ima...
introduction drought stress is one of the most important abiotic stresses all around the world. the aim of breeding studies and breeding for resistance to drought is that breeders seek to identify varieties and genetic resources to drought resistant and comparison of drought resistance among the varieties and the introduction of superior varieties to farmers. drought or imbalance between supply...
drought is a climatic phenomenon that causes much detrimental influence on ecological environments. this research investigates the performance of meteorological drought indices in different time scales in thetajan basin in iran. indices undergone in this study include: percent normal precipitation index (pnpi), z-score index (zsi), standard precipitation index (spi), china z index (czi), modifi...
drought is a major problematic phenomenon mostly for semi-arid areas of iran. during drought periods, reduction in vegetation levels causes such problems as soil erosion, surface runoff, flood risk, etc. therefore, the assessment of drought effects on plant covers is the most important issue. this research was conducted in 2015 using the extracted vegetation indices from moderate resolution ima...
Remote sensing is used for monitoring the impacts of meteorological drought on ecosystems, but few large-scale comparisons of the response timescale to drought of different vegetation remote sensing products are available. We correlated vegetation health products derived from polar-orbiting radiometer observations with a meteorological drought indicator available at different aggregation timesc...
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