Analysis of Severity, Duration, Frequency and Zoning Map of Meteorological Drought of Bakhtegan River Basin

Drought is the most important and most destructive climatic phenomena that impact is usually more important at a regional scale. This is important because the basin as Bakhtegan strategic situation of the region, the extent of farming lands and Bakhtegan - Tashk lake is obvious. The aim of this paper is drought monitoring using of standardized precipitation index and analysis of drought characteristics in timescale 3, 6, 12, 24 and 48 monthly and duration- frequency and magnitude – frequency. Also map zoning duration and magnitude drought in 20 return periods, analysis of maps drought occurred in the period of greatest intensity within the same period of 30 years (1981-2010) and precipitation and temperature trend is other objectives of this study. Result shown continuously from 2001 onwards, the case study suffered repeated droughts have been significant and stations located in the central and southern basin, bear continuation of a longer and more severe droughts, a higher frequency than the other stations. Curves of duration – return period and magnitude - return period of the scales showed that with increasing time scale and return period on the station, duration and magnitude drought increased. Analysis of duration and magnitude map zoning with 20 years return period shown that duration longer than is eastern region and magnitude higher than is southern and central region. Study of the highest severity drought shown that very severity drought imported from central and south region and exited from north.