Abstract With respect to the necessity of comprehensive studies on drought and also high damages that caused by drought, this research studied meteorological hydrological droughts. In study, Lighvan, Navroud Seqez basins with different climates were selected. We used monthly data stream flow, precipitation evaporation from 1992 2016 for study phenomena. The aim at is analyze SPI SPEI determinat...

drought is among the natural disasters that causes heavy damages to water resources and makes managers face serious challenges. drought monitoring is one of the important measures to manage droughts. different indices and methods employing varied indicators, have been developed in this regard. in this paper it is aimed to compare two well known meteorological indices of spi and edi with a hydro...

Drought is a stochastic natural hazard that is instigated by intense and persistent shortage of precipitation. Following an initial meteorological phenomenon, subsequent impacts are realized on agriculture and hydrology. Among the natural hazards, droughts possess certain unique features; in addition to delayed effects, droughts vary by multiple dynamic dimensions including severity and duratio...

Ecological fingerprints of climate change are becoming increasingly evident at broad geographical scales as measured by species range shifts and changes in phenology. However, finer-scale species-level responses to environmental fluctuations may also provide an important bellwether of impending future community responses. Here we examined changes in abundance of butterfly species along a hydrol...

Hydrological drought refers to a persistently low discharge and volume of water in streams and reservoirs, lasting months or years. Hydrological drought is a natural phenomenon, but it may be exacerbated by human activities. Hydrological droughts are usually related to meteorological droughts, and their recurrence interval varies accordingly. This study pursues to identify a stochastic model (o...

drought is random and nonlinear phenomenon and using linear stochastic models, nonlinear artificial neural network and hybrid models is advantaged for drought forecasting. this paper presents the performances of autoregressive integrated moving average (arima), direct multi-step neural network (dmsnn), recursive multi-step neural network (rmsnn), hybrid stochastic neural network of directive ap...

Severe drought periods followed by intense rainfall often leads to major floods in Mediterranean catchments. The resulting hydrology is complex and the response of solutes in the streams is often unpredictable. This study aimed to identify the most relevant factors controlling the hydrological responses to storms of an intermittent Mediterranean stream and to link those factors with dissolved o...