iran is located in dry belt of the earth and always involved with drought in different sections. drought has already caused many losses to natural plant cover, agriculture and human society. for drought monitoring, we can use some drought indecies. in this research, the standard index of annual precipitation)siap),sandardized precipitation index (spi) and palmer drought severity index (pdsi) we...

drought is a climatological hazard and is a part of the climate of a region. this climatological phenomenon has some properties that distinguish it from other natural disasters. drought is a gradual phenomenon and when the amount of moisture and precipitation become less than normal value in a certain period, its damages are non- structural in this condition and it is said that drought has occu...

In the Great Basin region of western North America, records of past climate and wildfire variability are needed not only for fire use, but also for understanding the mechanisms behind the centurylong expansion of piñon-juniper woodlands. The Mt. Irish area (Lincoln County, south-eastern Nevada) is a remote mountain ecosystem on the hydrographic boundary between the Great Basin and the Colorado ...

Drought is a normal, recurring feature of climate phenomena; it may occur virtually in all climatic regions. The effects of drought accumulate slowly and its impacts are spread over a larger geographical area than other natural hazards. Drought is a natural hazard originating from a deficiency of precipitation that result in a water shortage for some activities or some groups and is often assoc...

This articles presents a new series of maps showing the climate and environmental variability Botswana. Situated in southern Africa, Botswana has an arid to semi-arid climate, which significantly varies its different regions: Kalahari Desert, Makgadikgadi Pan Okavango Delta. While desert regions are prone droughts periods extreme heat during summer months, other experience heavy downpours, as w...

Aim Fire suppression, elk (Cervus elaphus Erxleben) browsing and drought have been suggested as possible explanations for low aspen (Populus tremuloides Michx.) ramet regeneration in elk winter range of the Greater Yellowstone Area (GYA) during the twentieth century. This study analyses the relationship between the rates of aspen regeneration, biophysical factors and human land use since 1830. ...