18O/16O and D/H of the Meteoric Waters in South Arabia.

Isotope study of moisture sources, recharge areas, and groundwater flow paths within the eastern Batinah coastal plain, Sultanate of Oman

“…Unfortunately, there is no continuous isotope sampling program in the Sultanate of Oman and the only meteorological station on the Arabian Peninsula with a regular isotope sampling program is the IAEA/WMO network station in Bahrain [ IAEA/WMO , 2001], located approximately 1000 km to the northwest of the study area. A comparison to previous rainfall isotope studies in northern Oman [ Cansult , 1986; Stanger , 1986; Wushiki , 1991; Macumber et al , 1997; Macumber , 1997, 1998] is complicated by the fact that none of these studies distinguished between rainfall from northern versus southern water vapor sources. The previously established local meteoric water line for the Batinah region (δ 2 H = 5.1 δ 18 O + 8.0 [ Macumber et al , 1997]) has to be considered an undifferentiated composite water line for all rainfall with northern and southern moisture sources.…”

“…Because the range of isotope values of the groundwater samples is almost identical to the range of isotope values in rainfall with a northern moisture origin, evaporation alone cannot explain the isotopic offset of groundwater samples from the LMWL‐N. According to Rayleigh fractionation calculation, a groundwater sample with a δ 18 O value of −3.5‰ would require a δ 18 O value in the source rainfall of at least −11‰, (h = 10%), which is significantly lower than the δ 18 O value reported for northern rainfall in the Batinah area (Figure 6) [ Stanger , 1986; Wushiki , 1991; Macumber et al , 1997]. As an alternative explanation for the displacement of the groundwater isotope values from the LMWL‐N and their placement between the two local meteoric water lines we propose that groundwater recharge takes place from a mixture of precipitation with a northern, Mediterranean water vapor source and an 18 O‐ and 2 H‐depleted Indian Ocean vapor source.…”

Stable Isotope Composition of Cyclone Mekunu Rainfall, Southern Oman

“…Symbol sizes reflect the rainfall amount of the corresponding interval (mostly 4 h). For comparison literature data for monsoon (daily samples), cyclones (grab samples), and Najd groundwater are shown: 1 = Clark (1987), 2 = Wushiki (1991), 3 = Strauch et al (2014), 4 = Macumber et al (1995), 5 = Lambs et al (2011), and 6 = Al‐Mashaikhi (2011). Note that there is no overlap with monsoon precipitation.…”

“…Second, the annual monsoon exhibits a unique isotopic signature as well. It shows a small δ value scatter, with δ 18 O and δ 2 H values ranging from −0.93‰ to 2.21‰ and from −2.1‰ to 23.7‰, respectively ( n = 153; Clark, 1987; Strauch et al, 2014; Wushiki, 1991). The reason for this small scatter and the similarity to the seawater signature (somewhat untypical for monsoon rainfall) is a relatively short atmospheric residence time and a first‐stage condensation process (Clark, 1987).…”

High resolution <sup>14</sup>C bomb-peak dating and climate response analyses of subseasonal stable isotope signals in wood of the African baobab – A case study from Oman

“…These tropical storms with heavy rainfall occur about once every three years (Pedgley, 1969;Hildebrandt and Eltahir, 2006;Strauch et al, 2014). Aside from intensity and duration, rainfall from the monsoon and cyclones usually differs distinctively in its respective isotopic signature (Clark et al, 1987;Strauch et al, 2014;Wushiki, 1991) (Fig. 1C, Table 1).…”