Faculty Publications
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Item Selection of Suitable General Circulation Model Outputs of Precipitation for a Humid Tropical Basin(Springer Science and Business Media Deutschland GmbH, 2022) Abraham, A.; Kundapura, S.Climate change has an observed effect on the environment and ecosystem. Climate change study aids in visualisation of changes in the environmental processes as well as development of planning and adopting the strategies. General circulation models (GCMs) are widely used in understanding present and projecting future climate change. The uncertainties associated with the climate projections is a major risk in impact assessment studies and could be reduced with considering GCMs suitable for the region. The study attempts to select a suitable subset of GCMs for precipitation simulation in the humid tropical basin, Achencoil, Kerala, India. Three statistical indicators, correlation coefficient (CC), normalised root mean square deviation (NRMSD) and absolute normalised mean bias deviation (ANMBD), are considered to evaluate the GCMs with the historical observations. The entropy technique is assigned to determine the weight of each performance indicator. Multi-criterion decision-making approaches, compromise programming (CP) and preference ranking organisation method of enrichment evaluation (PROMETHEE-2) are applied individually to rank the GCMs. The ranking is then integrated with group decision-making approach. The GCMs, MIROC-ESM-CHEM, MIROC-ESM, BCC-CSM1-1 and NorESM1-M occupied the first four positions in replicating the historical rainfall in the basin. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Identifying the Potential Impacts of Climate Change on Streamflow in a Humid Tropical Basin(Springer Science and Business Media Deutschland GmbH, 2023) Abraham, A.; Kundapura, S.The preservation of ecosystems in a river is based upon the replication of its original pristine conditions in the river regime. One of the main variables influencing a region’s hydrology is climate change. The research investigated the impact of climate change on the streamflow within the Meenachil River basin located in Kerala, India. The present study employed the Soil and Water Assessment Tool (SWAT) model to simulate the hydrological processes of the basin. The calibration and validation of the model are done, and the model performance is determined considering the Nash Sutcliffe Efficiency (NSE), coefficient of determination (R2), and percentage bias (PBIAS), and it is observed to be good. The data for the future climate are taken from National Aeronautics and Space Administration (NASA) Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data for Representative Concentration Pathway (RCP) 4.5. The response of streamflow to the climate in the future time period (2025–2099) is evaluated by considering three scenarios, S1, S2, and S3, with reference to a baseline scenario. In order to analyze the impact of climate change in the basin, the high and low flow indices (Q5 and Q95) of the scenarios under consideration are established using the flow duration curve of annual streamflow. Q5 showed a reduction of 20, 8.3, and 1.6% for the considered scenarios compared to the baseline period. The low flow index, Q95, showed an increase of 9.8, 15.3, and 15.1% in the scenarios concerning the baseline period. The findings of the present study will aid in developing adaption techniques for improved basin-wide management of water resources. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Juglans regia seeds have effects on platelets and peripheral fat deposition in the aorta and heart of C57BL/6J mice fed with normal and high fat simple carbohydrate diet(Bentham Science Publishers B.V. P.O. Box 294 Bussum 1400 AG, 2016) Prabhu, S.G.; Karkala, S.; Roy, N.; D'Souza, S.; Abraham, A.Background: Consumption of nuts particularly walnuts has been widely recommended for lowering the risk of coronary heart disease; however, very few studies have evaluated the potential unfavourable effects that Walnut seeds might have in vivo. Objective: To investigate the long-term effects of Juglans regia seed supplementation in specially formulated feed when fed to developed mice model. Method: C57BL/6J male mice were divided into four groups, labelled, C (control), T (High Fat Simple Carbohydrate-HFSC), Cw (control + walnut) and Tw (HFSC+ walnut) based on diet. Four mice from each group were sacrificed at the end of the first and fifth month respectively. Blood samples were collected every month. Bleeding time, blood platelet number and morphology were studied. Histopathological analysis of heart and aorta were also performed. Results: Groups Cw and Tw showed a significant increase in platelet count; however, platelet activation was not detected. There was a trend to an increase in bleeding time in group Cw. Expanded lumen diameter of the aorta was observed in Cw and Tw mice initially, however, it was found to constrict by the end of the study. A large amount of peripheral fat deposition in the aortas of Cw and Tw was observed, which increased through the course of the experiment. Conclusion: Kashmiri walnut seed supplementation was found to reduce the signs in shape change of platelets as well as increase platelet number with a trend to an increased bleeding time. This observation could be of medical interest. Histopathological analysis of heart and aorta showed lipid sequestration which merits further investigations. © 2016 Bentham Science Publishers.Item Spatio-temporal Dynamics of Land Use Land Cover Changes and Future Prediction Using Geospatial Techniques(Springer, 2022) Abraham, A.; Kundapura, S.Land use land cover (LULC) plays a key role in earth surface processes, and it is important to understand the spatio-temporal dynamics of LULC in an area. The study is carried out in the Meenachil and Manimala basins in Kerala, India, using land change modeller (LCM) to predict future LULC. The Random Forest (RF) classifier is used to classify the LULC in Google Earth Engine (GEE) for the years 1990, 2000, 2008, 2018 and 2021. The overall accuracy obtained for the years 1990, 2000, 2008, 2018 and 2021 is 92.53%, 91.42%, 96.92%, 87.79% and 95.54%, respectively, followed by a Kappa coefficient of 90.67%, 89.27%, 96.12%, 84.55% and 94.39%. LCM is utilised for LULC change detection, the model is validated successfully in predicting the LULC distribution in 2021, and the results were compared with the actual 2021 LULC. The results revealed the expansion of the built-up area and the decline of the agriculture class in these basins. The study then utilised LCM to predict future LULC up to the year 2050 at decadal intervals. The predicted future LULC maps revealed the drastic expansion of built-up; these basins might witness in the coming decades. The built area from 1990 to 2050 is expected to increase to 100.88 km2 and 60.75 km2 in Meenachil and Manimala basins, respectively. The agriculture area showed a decrease from 861.7 to 728.29 km2 in Meenachil and 743.5–676.89 km2 in Manimala basin. The outcome of the study showed the transformation of the considered land cover classes due to developmental activities in the region. The outcomes of the study can be considered as suitable inputs to land use planners for effective land use planning and management. © 2022, Indian Society of Remote Sensing.Item Assessing the Impacts of Land Use, Land Cover, and Climate Change on the Hydrological Regime of a Humid Tropical Basin(American Society of Civil Engineers (ASCE), 2023) Abraham, A.; Kundapura, S.Climate change and land use land cover (LULC) change are two major factors influencing river basin hydrology. This study explored these drivers' isolated and combined impacts on the ecologically relevant flow in the Achencoil basin, Kerala, India. The LULC classification in the study is carried out with the Random Forest (RF) algorithm in the Google Earth Engine (GEE) platform, and Land Change Modeler (LCM) is incorporated for change detection and projection. The future climate data from the National Aeronautics and Space Administration Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) is used for climate change impact assessment. The Soil and Water Assessment Tool (SWAT) is employed to simulate streamflow under LULC and climate change scenarios. The historical and projected future LULC change in the basin revealed an increase in the built-up and barren land, with a significant decrease in agricultural and forest areas. The results show that the projected future precipitation will decrease under the RCP 4.5 and increase under the RCP 8.5 scenario. The projected average maximum and minimum temperature are expected to increase under both scenarios in the basin. The LULC 2050 scenario shows the most significant rise in average annual streamflow, at 7.5%. Whereas in the climate change scenarios, the average annual flow decreases under RCP 4.5 and increases under RCP 8.5. The combined impacts of climate change and LULC change are relatively higher than the isolated effects of these drivers in the basin. The study outcomes are expected to help policymakers consider the effect of climate change and LULC change on the river's hydrology so as to implement the management activities that account for the riverine ecosystem. © 2023 American Society of Civil Engineers.