Hydrometeorological Observations and Modeling of an Extreme Rainfall Event Using WRF and WRF-Hydro during the RELAMPAGO Field Campaign in Argentina



Some of the most intense convective storms on Earth initiate near the Sierras de Córdoba mountain range in Argentina. The overarching goal of the RELAMPAGO field campaign, which was conducted near this mountain range during November-December 2018, was to observe these intense convective storms and their associated impacts. The field campaign had several components, including one focused on hydrometeorology, the goals of which were to 1) perform hydrological streamflow and meteorological observations in previously ungauged basins and 2) build a hydrometeorological modeling system for hindcast and forecast applications. ATMS Associate Professor Francina Dominguez and PhD student Sujan Pal were part of the RELAMPAGO field campaign.

Using RELAMPAGO datasets they helped collect, Pal and Dominguez were able to construct the stage–discharge curves in three basins, as hydrological instrumentation and personnel were successfully deployed based on RELAMPAGO weather forecasts. They found that the flood response time in these river locations is typically between 5 and 6 hours from the peak of the rain event. The satellite-observed rainfall product IMERG-Final showed a better representation of rain gauge–estimated precipitation, while IMERG-Early and IMERG-Late had significant positive bias. Their modeling work focused on the 48-h simulation of an extreme hydrometeorological event that occurred on 27 November 2018. Using the Weather Research and Forecasting (WRF) atmospheric model and its hydrologic component WRF-Hydro as an uncoupled hydrologic model, they developed a system for hindcast, deterministic forecast, and a 60-member ensemble forecast initialized with regional-scale atmospheric data assimilation.

Critically, their results highlight that streamflow simulations using the ensemble forecasting with data assimilation could provide realistic flash flood forecasts in terms of timing and magnitude of the peak. Their findings from this work are being used by the water managers in the region.

This article was published in the AMS Journal of Hydrometeorology. To see the rest of this article, please visit https://doi.org/10.1175/JHM-D-20-0133.1.