Reconstructing Floods in Data-Sparse Himalayan Region
Abstract
Floods are widespread natural disasters, having significant socio-economic impacts and need an appropriate modelling and management strategies. The hydrologic model based systems are often considered to be the most effective way for flood modelling. To drive a hydrologic model, input data for meteorology, land use, topography, etc. are required, amongst which rainfall estimates are most critical for an accurate flood simulation. In this regard, global reanalysis datasets and satellite rainfall products are commonly employed. However, the reliability of these datasets in data-sparse mountainous regions, such as Himalayas, is still unclear. Using Numerical Weather Prediction (NWP) models in conjunction with hydrologic models might be a plausible way to accurately simulate flood events. Through this work, an approach to improve the flood simulations available for the Himalayan region is presented, by developing a coupled hydro-meteorological system. The objective of this work is twofold: first, comparison of various rainfall datasets to obtain the dataset that is best representative of rainfall estimates in the Himalayan region, and second, to assess the accuracy of the flood discharge simulated from the coupled hydro-meteorological system. For the assessment, satellite rainfall product, global reanalysis datasets, and simulations from the Weather Research and Forecasting (WRF) NWP model are considered. Further, the WRF model is one-way coupled with the Variable Infiltration Capacity (VIC) hydrologic model to simulate the flood discharges in the Himalayan region. Separately, the VIC model is also driven with the satellite and the reanalysis datasets in a stand-alone mode to obtain the flood discharge estimates. The simulations from the coupled WRF-VIC model and the stand-alone VIC model are compared to evaluate the ability of the two modes to simulate the flood events. The analysis is conducted for three flood events that occurred over the upstream part of the Upper Ganga Basin (upUGB), located in the foothills of the Himalayas in northern India. The results indicated significant variability in the rainfall from different datasets, with WRF simulations being able to accurately represent the heavy rainfall in the region. The coupled WRF-VIC system is found to successfully simulate the flood discharges.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H41L2243C
- Keywords:
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- 1821 Floods;
- HYDROLOGYDE: 1869 Stochastic hydrology;
- HYDROLOGYDE: 4313 Extreme events;
- NATURAL HAZARDSDE: 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDS