Earth, Atmosphere & Environment Sciences
Title : | The role of water isotopes in understanding the hydrological cycle and its implication to palaeoclimatic studies |
Area of research : | Earth, Atmosphere & Environment Sciences |
Focus area : | Hydrology, Paleoclimatology |
Principal Investigator : | Dr. Anurag Kumar, Birbal Sahni Institute Of Palaeosciences, Lucknow, Uttar Pradesh |
Timeline Start Year : | 2023 |
Timeline End Year : | 2025 |
Contact info : | anuragkumar.geo@gmail.com |
Details
Executive Summary : | The stable isotopic compositions (d18O and dD) of water act as an important tracer to understand the atmospheric processes, recharge into water inventories and evaporation/evapotranspiration in watersheds. Over the past couple of decades, the stable isotope analyses of water samples have increased drastically in India. However, the spatio-temporal water isotope dataset from the Indian continent is still insufficient due to lack of systematic spatial sampling. The International Atomic Energy Agency (IAEA) has established a global network for isotopes in river (GNIR) and precipitation (GNIP) to monitor the spatio-temporal variation of d18O and dD values of river water and rainwater. However, even such a large-scale international program does not cover the spatio-temporal samples from India. At present, the isotopic dataset from India is highly scattered and limited to specific study sites. This limitation of the variation in the isotopic composition of different water reservoirs hampers the understanding of the hydrological cycle and also affects the modern calibration which is required in the palaeoclimatic study. The archaeological and palaeoclimatic study site where isotope study on samples of human bones, bivalves, speleotherms and calcrete requires modern calibration. However due to the lack of spatial datasets of modern samples, often the researchers are forced to use distant sites which is not a true representation of their sampling sites. Therefore in the present project, we propose to map the spatial isotopic composition of shallow groundwater samples from the Ganga river basin (GRB) so that any archaeological or paleoclimatic study can use modern calibrations. The advantage of selecting shallow groundwater aquifers is that it represents the average isotopic composition of rainwater over a period of time. Ideally, modern calibration for palaeoclimatic studies should sample modern rainwater. However, regular collection of rainwater samples for an extended period of time is logistically difficult at such a large scale. In such a scenario, the collection of groundwater samples provides the best alternate option for the average isotopic signature of the rainwater. In addition to the collection of groundwater samples, we also aim to collect river water samples from the GRB. These datasets would significantly help in characterizing the isotopic composition of groundwater, river water and rainwater from the GRB. In addition to a modern analogue for the palaeoclimate reconstruction, the stable isotopes of water would also provide added information of the present hydrological cycle operating in the GRB. Dense sampling would help to map the stable isotopic composition of water in the GRB. These isotopic datasets would be compared with the regional rainwater and river water to understand the evaporative loss of water before reaching to the ground. It would also help in demarcating the region where the groundwater and river water mixing is high. |
Total Budget (INR): | 25,32,400 |
Organizations involved