Isotopic and chemical composition of precipitation in Riyadh, Saudi Arabia

摘要: Abstract Only limited data on the isotopic and chemical composition of Riyadh rain are currently available. In this study, we complement these by analyzing integral samples covering 28 precipitation events between 2009 2013. Results stable isotope analyses used to establish a Local Meteoric Water Line: δ 2 H = 5.22(± 0.38) · δ 18 O + 14.8(± 0.9) ‰. Moisture source-related fingerprints masked continental effect, altitude sub-cloud evaporation, moisture recycling. The study one event for intra-storm variability revealed strong depletion due rainout Rayleigh distillation processes, thus highlighting general need samples. Tritium grab from 12 yielded concentrations 2.8 6.4 tritium units (TU), which close natural background few TU. Major ion ratios indicate that solutes predominantly derived atmospheric dust originating limestone outcrops sabkha deposits. latter play role with respect elevated Cl − Na + contents, but probably also responsible SO 4 2 − part Ca 2 + found in rain. Observed intra- inter-storm variabilities major levels necessitate collection calculation precipitation-weighted means, respectively. obtained signatures mean concentration (9.5 mg L − 1 ) may be useful groundwater assessments, e.g., identification modern recharge quantification thereof means Chloride Mass Balance method.