Implementation of WRF-Hydro at two drainage basins in the region of Attica, Greece, for operational flood forecasting

Abstract

Abstract. An integrated modeling approach for forecasting flood events is presented in the current study. An advanced flood forecasting model, which is based on the coupling of hydrological and atmospheric components, was used for a twofold objective: first to investigate the potential of a coupled hydrometeorological model to be used for flood forecasting at two medium-size drainage basins in the area of Attica (Greece) and second to investigate the influence of the use of the coupled hydrometeorological model on the precipitation forecast skill. For this reason, we used precipitation and hydrometric in situ data for six flood events at two selected drainage regions of Attica. The simulations were carried out with the Weather Research and Forecasting (WRF) model (WRF-only) and the WRF-Hydro system in a fully coupled mode, under which surface, subsurface, and channel hydrological processes were parameterized at a fine-resolution grid of 95 m approximately. Results showed that the coupled WRF-Hydro system was capable of producing the observed discharge during the flood episodes, after the adequate calibration method applied at the studied basins. This outcome provides confidence that the model configuration under the two-way atmospheric–hydrological coupling is robust and, thus, can be used for operational flood forecasting purposes in the area of Attica. In addition, the WRF-Hydro model showed a tendency to slightly improve the simulated precipitation in comparison to the precipitation produced by the atmospheric-only version of the model (WRF), demonstrating the capability of the coupled WRF-Hydro model to enhance the precipitation forecast skill for operational flood predictions.

A Numerical Investigation of Hurricane Florence‐Induced Compound Flooding in the Cape Fear Estuary Using a Dynamically Coupled Hydrological‐Ocean Model

“…It is an integrated system incorporating a land surface model (LSM), grid aggregation/disaggregation, subsurface flow routing, overland flow routing, and channel routing (Figure 1). WRF‐Hydro has been successfully applied to simulate flooding events in different environment settings (e.g., Galanaki et al., 2021; Majidzadeh et al., 2017; Pal et al., 2021; Ryu et al., 2017; Wehbe et al., 2019). It also serves as the core of the National Ocean and Atmospheric Administration's National Water Model (NWM; https://water.noaa.gov/about/nwm) which provides streamflow forecasting over the entire continental United States.…”

A Review on the Development of Two-Way Coupled Atmospheric-Hydrological Models

“…For example, Gu et al [71] used the WRF-Hydro to conduct flood simulations in the Qingjiang River Basin (at a resolution of 1 km in LSM and 100 m in hydrological model) based on European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data; with calibrated parameters, the Nash-Sutcliffe efficiency (NSE) of simulated floods ranges from 0.50 to 0.94. Galanaki et al [72] implemented the WRF-Hydro to simulate flood events in two drainage areas of Attica, Greece, and the results show that the model can reproduce the river discharge after adequately calibrating for the studied basins. Kerandi et al [65] used the WRF-Hydro for hydrometeorological simulations in the Tana River basin of Kenya, East Africa, driven by ERA-Interim data; the model can effectively estimate annual runoff, but it underestimates peak flow (the NSE is 0.02) at the daily scale.…”

“…High-or superhigh-resolution hydrometeorological simulations are key study topics, but this requires powerful computational ability and a large number of datasets to support it. In this case, the high-resolution hydrometeorological simulations were carried out mainly for small domains/watersheds [28,70] or short time periods [72,73]. It might be difficult to reflect the influence of hydrological processes on the atmosphere at large spatiotemporal scales, hence we need to pay more attention to hydrometeorological studies over longer time scales [84] and larger catchment scales [31,32]; (4) Improving parameterization schemes.…”

The Role of Parameterizations and Model Coupling on Simulations of Energy and Water Balances – Investigations With the Atmospheric Model WRF and the Hydrologic Model WRF‐Hydro

“…The impact of lateral terrestrial routing on precipitation has gained attention in previous fully‐coupled WRF‐Hydro studies, because of the possible feedbacks enhanced by the coupling of the atmosphere with the hydrological processes. A reduction of the bias of the total simulated precipitation (2.7%–10%) by coupled WRF‐Hydro, compared to WRF, was found for a number of storm events in central Israel (Givati et al., 2016) and in Attica, Greece (Galanaki et al., 2021). Zhang et al.…”