Accurate and reliable drought monitoring is essential to drought mitigation efforts and reduction of social vulnerability. A variety of indices, such as the standardized precipitation index (SPI), are used for drought monitoring based on different indicator variables. Because of the complexity of drought phenomena in their causation and impact, droughtmonitoring based on a single variable may b...

introduction: drought is a natural and recurrent feature of climate. the characterizations of it may change under the effect of climate change in future periods. during the last few decades a number of different indices have been developed to quantify drought probabilities. droughts are caused by disruptions to an expected precipitation pattern and can be intensified by unusually high temperatu...

Babolsar eastern coastal dunes have been developed along the southern coast of the Caspian Sea. The studied area is coordinated in N36°43' to N36°44' latitude and E52°44' to E52°52' longitude. The objectives of this research were to: Study mineralogy and geochemistry of sand dunes, to obtain chemical alteration index (CIA) and its relationship to climate and mineralogy, to de...

the normalized difference vegetation index (ndvi) derived from the spot 4 satellite has been widely used to monitor moisture-related vegetation condition. the relationship between vegetation and climate index, however, is complex and has not been adequately studied with satellite sensor data. to better understand this relationship, an analysis was conducted on time series of monthly ndvi (1999–...

Drought is a complex and highly destructive natural phenomenon that affects portions of the United States almost every year, and severe water deficiencies can often become catastrophic for agricultural production. Evapotranspiration (ET) by crops is an important component in the agricultural water budget; thus, it is advantageous to include ET in agricultural drought monitoring. The main object...

[1] The probabilities of the occurrence of extreme dry/wet years and seasons in Europe are estimated by using two ways of the Standardized Precipitation Index (SPI and SPI-GEV) and the Standardized Nonstationary Precipitation Index (SnsPI). The latter is defined as the SPI by fitting precipitation data with a nonstationary Gamma distribution in order to model the precipitation time dependence u...

Insect prey of the Namib golden mole congregate beneath clumps of grass scattered among the sand dunes of the Namib Desert. In the presence of the light winds that typically blow over the Namib Desert, these grass clumps emit low-amplitude vibrations that are transmitted through the sand. While foraging in the sand-swimming mode (a few centimeters below the surface of the sand), some moles appa...