| Autor: |
Ahmed N; Isotope Hydrology Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, Savar, Bangladesh., Kurita N; Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan., Chowdhury MAM; Department of Physics, Jahangirnagar University, Savar, Bangladesh., Gao J; Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, People's Republic of China., Hassan SMQ; Bangladesh Meteorological Department, Storm Warning Centre, Agargaon, Bangladesh., Mannan MA; Bangladesh Meteorological Department, Storm Warning Centre, Agargaon, Bangladesh., Mallik MAK; Bangladesh Meteorological Department, Storm Warning Centre, Agargaon, Bangladesh., Choudhury SA; DMO, Bangladesh Meteorological Department, Sylhet, Bangladesh., Bhuiyan MAQ; Isotope Hydrology Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, Savar, Bangladesh., Karim MM; Isotope Hydrology Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, Savar, Bangladesh. |
| Abstrakt: |
The study investigates the factors that control the isotopic composition of tropical precipitation in Bangladesh. Daily and monthly rainfall samples were collected from three stations from 2013 to 2015: (1) northern and moderately high altitude: Sylhet, (2) middle part of the country (close to Tropic of Cancer): Savar, and (3) southern coastal region: Barisal. To escape from the post-evaporation effect, proper care was adopted. This is supported by the fact that the local meteoric water lines (LMWLs) derived for the daily precipitations of all stations mostly follow the global meteoric water line (GMWL). The results exhibit a clear seasonal and spatial variation in both δ 18 O and δ 2 H of precipitation. 18 O is more depleted in samples collected during rainy (monsoon) seasons, while 18 O enrichment is associated to winter and summer (pre-monsoon) seasons. During rainy season, intra-seasonal variability of δ 18 O rainfall is clearly seen and remarkable depletion of 18 O is observed during the period of intense convective activity over the Bay of Bengal. This feature indicates that isotope variability in Bangladesh is controlled by large-scale convective activity rather than local rainfall amount. |
