The effect of the length of record on the standardized precipitation index (SPI) calculation was investigated by examining correlation coefficients, the index of agreement, and the consistency of dry/wet event categories between SPI values derived from different precipitation record lengths. The effect was also illustrated by comparing SPI values derived from different lengths of record in some...

based on spi and rdi indices, changes in droughts in the semi-arid areas of west golestan province was assessed in the gis environment by incorporating data from hashemabad synoptic station and 11 climatic stations. after evaluating the ability of lars-wg5 in the simulation period (1984-2010), downscaling of hadcm3, ipcm, and gfc models was done as a group under scenarios of a1b, a2 and b1 to e...

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...

aridity and drought are two inevitable occurrences of the climate change in the region. so, any kinds of planning and futurism, without regard to them, lead to failure. climate change cause drought phenomenon. the anomalies and irregularities in the precipitation mainly cause drought. fars province, one of the important centers of agriculture, population and industry in the country, with specif...

This study quantifies the sensitivity of surface runoff to drought and climate change in the Diyala watershed shared between Iraq and Iran. This was achieved through a combined use of a wide range of changes in the amount of precipitation (a decline between 0% and −40%) and in the potential evapotranspiration rate (an increase between 0% and +30%). The Medbasin-monthly rainfall-runoff model (Me...

Meteorological drought monitoring is important for drought early warning and disaster prevention. Regional meteorological drought can be evaluated and analyzed with standardized precipitation index (SPI). Two main processing schemes are frequently adopted: (1) mean of all SPI calculated from precipitation at individual stations (SPI-mean); and (2) SPI calculated from all-station averaged precip...

abstract drought is a natural creeping event that starts due to lower moisture compared to normal condition. this phenomenon impacts all aspects of human activities. however there is neither any detailed definition nor a general and proper index for drought monitoring. in this study, fuzzy logic has been applied to deal with inherent uncertainties of the real world data. we presented a fuzzy mo...

     Drought as a natural phenomenon characterized by a significant decrease of water availability during a period of time and over a large area. In recent years, droughts and its frequent in arid and semi-arid regions like Iran on the one hand, and water demand has been rising on the other hand and, as a result, their impacts are being aggravated. Therefore, the meteorological and hydrological...

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,...