The effects of moisture sources and local parameters on the ¹⁸O and ²H contents of precipitation in the west of Iran and the east of Iraq

Abstract

Iran and Iraq face a water shortage crisis especially in the recent decade. Hence, the regions with high potential water resources are highly important to these countries. Precipitation sampling for ¹⁸O and ²H analyses was conducted in 10 stations in the west of Iran and 2 stations in the east of Iraq during this study. Studying precipitation and its moisture sources using the backward trajectories of the HYSPLIT model, developing seasonal meteoric water lines (MWLs), and simulating the spatial variations of stable isotopes in precipitation using stepwise regression yielded valuable results regarding the hydrometeorology of the study region. The precipitation moisture sources in the study region were determined using the backward trajectories of the HYSPLIT model. These backward trajectories demonstrated the domination of various moisture sources including the Mediterranean Sea, the Black Sea, the Red Sea, and also the Persian Gulf in different seasons as reflected in the seasonal MWLs. In addition to moisture sources, the effects of meteorological parameters (temperature and precipitation amount) on the stable isotope content of precipitation also showed a notable correlation (with R² = 0.58 and 0.46, respectively). Surface water resources were also plotted on the developed seasonal MWLs, while some samples deviated from seasonal MWLs due to the evaporation effect.

Keywords:

• stable isotopes
• moisture sources
• HYSPLIT
• stepwise regression
• ANCOVA test

Acknowledgments

Our special thanks to the Meteorological Organizations of the western provinces of Iran, namely Kermanshah, Kurdestan, and Ilam for their help in providing meteorological data and sampling stable isotopes. We gratefully acknowledge Dr. Ramon Aravena for his partial financial support and Mr. R. Elgood and J. Harbin for their help with the geochemical and isotope analyses at the University of Waterloo-Environmental Isotope Laboratory (UW-EIL), Canada.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

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