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Title (Primary) Stable isotope composition of Cyclone Mekunu rainfall, Southern Oman
Author Müller, T.; Friesen, J.; Weise, S.M.; Al Abri, O.; Bait Said, A.B.A.; Michelsen, N.;
Journal Water Resources Research
Year 2020
Department HDG; CATHYD;
Volume 56
Issue 12
Language englisch;
POF III (all) T31;
Data links https://doi.pangaea.de/10.1594/PANGAEA.909045
Supplements https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1029%2F2020WR027644&file=wrcr24954-sup-0001-2020WR027644-SI.docx
Keywords tropical cyclone; stable isotopes; precipitation; paleoclimate; Oman; Arabian Sea
Abstract Cyclone Mekunu hit the southern Arabian Peninsula in late May 2018 and brought rainfall amounts that accounted for up to six times the mean annual precipitation. Coming from the Arabian Sea, a quite underdocumented region with regard to cyclones, the storm eye crossed the Omani coast approx. 80 km east of the border to Yemen. Using automatic samplers, rainfall samples were collected during the event at three locations along a transect almost parallel to the storm track. The stable isotope analyses show a wide range of δ values, with minimum and maximum values of ‐17.01 and ‐1.77 ‰ δ18O and ‐122.2 and ‐1.6 ‰ δ2H. On average, rainfall becomes isotopically lighter with elevation, but rather irregularly. In view of high wind speeds probably precluding a gradual rain‐out of ascending air masses, a “pseudo elevation effect” seems likely. Our measurements expand the known δ value range of local cyclones by about 6 ‰ for δ18O and by nearly 50 ‰ for δ2H. The isotopic composition of the annual Indian Summer Monsoon shows values of ‐0.93 to 2.21 ‰ δ18O and ‐2.1 to 23.7 ‰ δ2H. Thus, there is a clear difference in the dual isotope signatures of the two precipitation systems in the area. Our findings enable an assessment of the impact of cyclones on the hydro (geo)logical system. For the arid Najd area, we demonstrate that the isotopic signatures of groundwater samples fall between those of cyclone and (paleo)monsoon precipitation, suggesting that several rainfall types may have contributed to replenishment.
ID 23795
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=23795
Müller, T., Friesen, J., Weise, S.M., Al Abri, O., Bait Said, A.B.A., Michelsen, N. (2020):
Stable isotope composition of Cyclone Mekunu rainfall, Southern Oman
Water Resour. Res. 56 (12), e2020WR027644