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RISS 인기검색어
- 검색키워드
- 저자 : Kattan Zuhair (검색결과 2 건)
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Spatial Mapping of Atmospheric Precipitation Isotopes in Syria
Zuhair Kattan 한국대기환경학회 2021 Asian Journal of Atmospheric Environment (AJAE) Vol.15 No.2
Stable isotope ratios (δ2H and δ18O), tritium (3H). and deuterium excess (d-excess) values of atmospheric precipitation (P) at 16 stations were determined for mapping the spatial variation of oxygen and hydrogen P isotopes in Syria. The major geographical parameters (longitude east, LE; latitude north, LN; altitude, H; and inland distance from the coast, DFC) were used to find out the best fitting models for the spatial mapping of atmospheric P isotopes in Syria. The highest correlation coefficients (r>0.73) were found for the relationships δ18O-H and δ2H-H. The impacts of LE and LN factors were rather moderate (0.3<r<0.6). However, a high correlation coefficient (r>0.7) was found for the relationship d-excess-LN. The increase of d-excess value from 23‰ to 24‰ in southern Syria is due to the Mediterranean Sea (MS) moisture, likely as a high percentage (>65%) of prevailed winds usually comes over the MS. The concentrations of 3H in P samples (4-14 TU) during the period 1989-1993 were higher than those (3-10 TU) for the period 2004-2006, indicating thus a return back toward the levels of typical 3H production in nature. The high correlation coefficients (r>0.59) that were found for the relationships 3H-DFC and 3H-LE, suggest a continuous exchange between the low tritium moisture from the MS and the higher tritium moisture from the inland areas. Produced gridded isotopic values are quite satisfactory for covering certain areas in Syria and the neighboring Arab countries.
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Kattan Zuhair,Nasser Saeid 한국대기환경학회 2023 Asian Journal of Atmospheric Environment (AJAE) Vol.17 No.1
Records of stable isotopes (2H and 18O), deuterium excess (d-excess) and tritium (3H) values in precipitation (P) during 1990–2022, together with long-term time series (1919–2022) of air temperature (T) and P-amount values at the Damascus station, were analysed to explore the seasonal and annual variability patterns of those parameters in P and assess the vulnerability to climate change in this area. Variation of the annual average air T values over the period 1919–1969 shows an increase gradient of ≈ + 0.1 °C/decade. However, a remarkable much higher gradient (+ 0.64 °C/decade) is calculated for the period 1990–2022. The average P-amount value calculated for the last three decades (≈185 mm) was lower by ≈28 mm, compared to the value (≈213 mm), relative to the reference period (1919–1969). This significant decline in the annual P-amount value by ≈11–13%, accompanied by an annual heating of 0.2–0.6 °C/decade in the annual air T, is likely the result of the climate change affecting this area. The linear relationships between annual average δ18O and annual average δ2H values versus time over the period 1990–2019 indicate increased gradients in both stable isotopes (≈0.3–0.5‰ and ≈1.1–3.2‰ per decade for δ18O and δ2H, respectively), accompanied with a decrease gradient of ≈0.9–1.1‰ per decade in d-excess values. Variability of annual 3H concentrations towards low levels (< 6 TU) during the later years strongly suggests the return back towards the cosmogenic production of this radioisotope in the upper atmosphere. Information gained from this work would offer new insights to improve the understanding of the temporal variability of P isotopes and assess the risks associated with climate change on the natural water resources in the Eastern Mediterranean region.
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