Regional Annual Extreme Drought Period Frequency Analysis Using L-moments in Iran
2014
Heydari Zadeh, Majid | Sarhaddi, Ali | Ghafourie, Abdol majid
In this study, drought was analyzed based on Dry Spells (days of no rainfall). It was selected 67 synoptic stations with appropriate long duration and uniform distribution in the country. The Minimum duration of daily rainfall records 17 years was for Semnan station and the maximum duration of 56 years was for Tabriz station (and several other stations). Sort of daily precipitation was applied in the EXCEL software to determine the number of Dry Spells in each years and stations. In this study FREQ program in MATLAB software was used for frequency analysis. Eight regional homogeneous categories were found and regional analysis on Dry Spells was performed. The results show that dry quantities and dry duration will change in different regions. The Dry Spells are unstable and variable with different return periods in the North West and South-East countries. It was known that Southern region (especially the Persian Gulf and Oman Sea) and the central region as most sensitive areas in terms of reduced rainfall and increasing number of days without precipitation in different return periods
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