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...

In this study, we used the time series images of spectral reflectance from TERRA satellite to compute normalized difference vegetation index (NDVI) and normalized difference moisture index (NDMI) in the Chaoyang City, western Liaoning, north-eastern China. Time-series data of NDVI and NDMI derived from satellite images of the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to sh...

comparability analyses are performed to investigate similarities/differences of the standard precipitation index (spi) and the reconnaissance drought index (rdi), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (et0). data are from six synoptic stations in south khorasan province in iran.at the first for calculating spi, the elevation-precipita...

Comparability analyses are performed to investigate similarities/differences of the standard precipitation index (SPI) and the reconnaissance drought index (RDI), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (ET0). Data are from six synoptic stations in south Khorasan province in Iran.At the first for calculating SPI, the elevation-precipita...

The aim of this study is to investigate climate change impact on Karoon3 basin in future periods. For this purpose, the simulated precipitation of 10 AOGCM models, including BCM2.0, CGCM3T63, CNRMCM3, CSIROMK3.0, GFDLCM2.0, GISS-ER, HADCM3, INMCM3.0, IPSLCM4, MIROC3.2 MEDRES was used to simulate drought index. Monthly precipitation was calculated by inverse distance weighted method. Standard Pr...

Comparability analyses are performed to investigate similarities/differences of the standard precipitation index (SPI) and the reconnaissance drought index (RDI), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (ET0). Data are from six synoptic stations in south Khorasan province in Iran.At the first for calculating SPI, the elevation-precipita...

In this research, using technique for order-preference by similarity to ideal solution (TOPSIS) index, drought phenomenon is determined and ranked. For this purpose, using 5 atmospheric elements including temperature, wind, precipitation days, annual precipitation, precipitation concentration index (PCI), droughts occurred in Shiraz station for 20-year statistical period (1983-2003) have been d...

Droughts are one of the most damaging climatic phenomena, and the most complex natural hazard  which affects the economy, agriculture, public health and environment in large areas. The aim of this study is to compare drought indicators derived from tropical rainfall measuring mission (TRMM) data in the south of Iran. Also the TRMM rainfall was considered, so as to investigate changes in the rai...

drought as a natural but temporary imbalance of water availability is the interaction between natural environment and human life resulting in diminished water resources availability and reduced carrying capacity of the ecosystems. drought indices are essential elements for an efficient drought monitoring system. these indices make the transforming information of climatic anomalies easier and al...