Evaluation of precipitation and river discharge va

Authors: Azadeh Arbabi Sabzevari Mohammad Zarenistanak Hossein Tabari Shokat Moghimi

Publish Date: 2015/03/20

Volume: 124, Issue: 2, Pages: 335-352

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Abstract

This study investigates trend and change point in the annual and monthly precipitation and river discharge time series for a 56year period 1956/57–2011/12 The analyses were carried out for 17 rain gauge stations and 13 hydrometric stations located in the southwest regions of Iran Five statistical tests of Mann–Kendall Spearman Sequential Mann–Kendall Pettitt and Sen’s slope estimator were utilized for the analysis The relationships between the precipitation and river discharge series were also examined by the Pearson correlation test The results obtained for the precipitation time series indicated that most of the stations were characterized by insignificant trends for both the annual and monthly series The analysis of discharge trends revealed a significant increase during both the annual and October through April series The magnitude of significant increasing trends in annual river discharge ranged between 665 and 2049 m3/s per decade The highest number of significant trends in the monthly river discharge series was observed in January and February accounting for seven and four trends respectively Furthermore most of the annual and monthly river discharge series showed significant change points in the 1970s It was also found that river discharge was strongly correlated with precipitation at the annual scale and for most of the monthsThe authors are thankful to the Islamic Republic of Iran Meteorological Organization IRIMO and Water Resources Management Organization of the Ministry of Energy Islamic Republic of Iran for providing observed data They also thank the anonymous reviewers for their comments and suggestions which helped in improving the paper

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