نتایج جستجو برای: palmer drought severity index
تعداد نتایج: 561124 فیلتر نتایج به سال:
Reducing or increasing the climate parameters such as temperature and rainfall as a result of the climate change process, causes a variety of droughts. In this study, the effect of climate change on meteorological drought in Yazd province is investigated. For this purpose, the drought time series were determined in two historical periods (1961-2005) and the future (2017-2100) by SPI and SPEI. H...
In this paper, after stating the characteristicof some of continuous distributions including, gamma, Crovelli’s gamma, Rayleigh, Weibull, Pareto, exponential and generalized gamma distribution with each other,these distributions were fit on drought data of Guilan state and the best distribution was presented. Then, severity and duration of the drought of different sites were investigated usi...
Drought is one of the most destructive natural disasters in human societies that cause irreparable impacts on agriculture, environment, society and economics. So, awareness of occurrence of droughts can be effective in reducing losses. In this study, in order to modeling and forecasting drought severity in a 37 year time period (1971-2007) in 21 meteorological stations, located in the cold semi...
The purpose of this study is analyzing the trend of drought characteristics in Hamedan Province In this regard, the corrected standardized precipitation index (SPImod) was calculated based on the monthly precipitation data from 11 synoptic and rain gauge stations during the period of 1985-2013. Drought characteristics, including severity, duration and interarrival time were defined and extracte...
Fire history of a ponderosa pine-mixed conifer forest was investigated in the Whiskeytown National Recreation Area, southeastern Klamath Mountains, California. Fire return intervals were found to be frequent and similar to other comparable forests in California. Median fire interval for the six sample plots (1.4–1.7 ha) ranged from 2 to 4 years (mean range, 4.8–7.4 years). Most fires (93%) occu...
Midlatitude regions experienced frequent droughts during the twentieth century, but their impacts on terrestrial carbon balance are unclear. This paper presents a century-scale study of drought effects on the carbon balance of terrestrial ecosystems in China. The authors first characterized the severe extended droughts over the period 1901–2002 using the Palmer drought severity index and then e...
Unlike the major droughts of the twentieth century that are readily identified in the instrumental record, similar events in the nineteenth century have to be identified using a combination of proxy data, historical accounts and a sparse collection of early instrumental records. In the USA, three distinct periods of widespread and persistent drought stand out in these records for the latter hal...
In this study, the trophic status of the Bustan dam reservoir was investigated using Palmer and Carlson indices. Biological parameters including phytoplankton and environmental factors such as phosphate, nitrate and chlorophyll were sampled at the depth of 0.5 meter in five stations in three replicates seasonally in 2019, repetitions and Then the Palmer and Carlson indices were determined. The ...
Investigating the trend of changes in drought as one of the natural disasters is essential. For this purpose, in the present study, the trend of changes in standardized precipitation-evapotranspiration drought index (SPEI) for the synoptic stations of Kerman province was evaluated for the years 1990 to 2018. The change trend of the SPEI time series was evaluated using two both Mann-Kendall and ...
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