A multimodel ensemble using the entropy-TOPSIS method for projecting temperature for the Lower Tapi River Basin Nirav Agrawal, Dr S. S. Mujumdar Water Practice and Technology, 2025 General Circulation Models (GCMs) developed by scientist and researchers, are often used for predicting future trends in climate parameters need downscaling to regional scale and bias corrections. This study aims to use Entropy-TOPSIS approach to rank 13 bias corrected CMIP6 models for Lower Tapi River Basin (LRTB). Using five performance indicators, R2 Score, KGE, Spearman's Correlation ρ, MAE and Standard Error. The entropy method gives weights to these performance indicators and TOPSIS method was used to rank the models based on performance indicator. A Sensitivity analysis was performed using 5000 iterations on differential weights to check the robustness of the ranking. The study found EC-Earth3, CanESM5, EC-Earth3-Veg, INM-CM4-8, INM-CM5-0 as top performer for modeling Tmax and ACCESS-ESM1-5, BCC-CSM2-MR, ACCESS-CM2, EC-Earth3-Veg, EC-Earth3 as top performer for Tmin for the given study area. An ensemble model was developed using REA weights to study the change in temperature. The study found increase in Tmax from 0.9 °C to 2.0 °C and Tmin as 1.34 °C to 2.7 °C for period of 2015–2099 under various scenarios. The study will help researchers in climate studies over Lower Tapi River basin such as Water Quality Studies, Evapotranspiration, Effect of temperature on Agriculture, Soil moisture content and other hydro-climatic studies.
Use of Satellite-Based Remote Sensing Indices for Agricultural Drought Monitoring in Saurashtra, Gujarat Jinal Nishant Shastri, Sanskriti S. Mujumdar Meteorological Applications, 2025 Drought, a significant natural hazard, continues to pose considerable threats to agriculture, particularly in arid and semi‐arid regions. Timely and accurate monitoring of drought conditions is essential for effective mitigation and adaptation strategies. This study evaluates the efficacy of three remote‐sensing‐based drought indices: VCI, TCI, and VHI in detecting and monitoring agricultural drought in the Saurashtra region of Gujarat. The research employs MODIS (moderate resolution imaging spectroradiometer)‐derived NDVI (normalized difference vegetation index), and LST (land surface temperature) data to compute the indices. To validate these remotely sensed indices, their values were correlated with the standardized precipitation index (SPI) calculated for 3‐, 6‐, and 12‐month reference periods using precipitation data from the India Meteorological Department (IMD). Furthermore, the spatial distributions and index values were compared between 2002, identified as a drought year by IMD, and 2023, considered a normal reference year. The results indicate that VHI shows the strongest correlation with SPI‐6 ( r = 0.67), followed by SPI‐3 ( r = 0.49) and SPI‐12 ( r = 0.40). This finding aligns with the Standardized Precipitation Index User Guide (WMO‐No. 1090, World Meteorological Organization), which recommends using SPI‐6 for agricultural drought assessment. Both VCI and TCI exhibit a moderate correlation with SPI‐6 ( r = 0.62 and 0.56, respectively) but weaker correlations with SPI‐12 ( r = 0.39 and 0.37). The spatial comparison of VCI, TCI, and VHI between 2002 and 2023 demonstrates that VHI effectively captures the intensity and extent of drought, as it integrates vegetation and thermal stress. Overall, the study highlights the potential of VHI as a reliable, remote‐sensing‐based drought indicator that provides timely information on drought severity and spatial extent, particularly in arid and semi‐arid regions. Integrating VHI with soil‐moisture data could yield an even more robust composite drought index for policymakers and agricultural stakeholders to support strategies that mitigate the adverse impacts of drought on crop production and livelihoods.
Analysis of Monthly and Daily Annual Extreme Precipitation for Urban Vadodara Chirayu Pandit, Sanskriti Mujumdar Disaster Advances, 2025 Human intervention due to change in landuse landcover, emission of greenhouse gases and aerosols affects local climate. Spatial analysis of long term annual rainfall and very wet days of 5 years’ time window of rural and urban stations of Vadodara district reveals that urban annual rainfall is rising as compared to surrounding peri-urban and rural rainfall. One-day annual extreme rainfall is important for understanding and establishing impacts of climate change. Information about occurrence of extreme precipitation is of utmost importance for flood mitigation. One-day annual extremes and consecutive 5 day extremes are important for research in climate change. If the likelihood or probability of occurrence of month of extreme value is known in advance, it can play, big role in preparedness of local governing bodies in tackling resulting problem due to extreme event. One-day annual extremes can give clear picture about flash flood occurrence. This study analyzes monthly one-day annual extreme values for a period of 90 years for Vadodara. It helps us to analyze the pattern of occurrence and more specifically month of occurrence for one-day extremes. GEV distribution for June, July, August, September and October month in one-day extreme annual rainfall series was fitted. Results show gradual change in pattern of occurrence for months of July and August with occurrence of one-day annual extreme gradually converging towards July.
Evaluation of the impact of anthropogenic storage on the hydrological drought propagation in two contrasting semi-arid river basins Akshay Pachore, Nirav Agrawal, Nurmuhammadkhon Omonov, Komiljon Rakhmonov, Gulomjon Umirzakov, et al. Journal of Water and Climate Change, 2024 This study quantitatively investigated reservoir-effects on drought propagation in two semi-arid river basins: India’s Tapi basin with the Ukai reservoir and Uzbekistan’s Chirchik basin with the Charvak reservoir. Meteorological drought (MD) is analyzed using the Standardized Precipitation Index (SPI) and hydrological drought (HD) using the Standardized Streamflow Index (SSI) for the duration from 1980 to 2004. Both the river basins, especially in upstream reservoir areas, exhibited a notable correlation between HD and MD. Reservoir operation was observed to reduce the downstream MD–HD correlation at shorter SPI timescales. Hit-score-based evaluations indicated that reservoir operation has induced changes in the drought propagation patterns for both river basins. Due to the contrasting characteristics, the river basins showed a significant variation in the drought propagation time (DPT), with distinct influences from monsoon (Tapi) and snow-melting (Chirchik). The average DPT (average DPT over 12 months) for the reservoir-influenced part of the Tapi (∼ six months) and Chirchik (∼ nine months) basins is higher than that of the natural parts of both basins (Tapi: ∼ four months; Chirchik: ∼ six months) as a result of the natural and anthropogenic storage influence.