scholarly journals Extending the Predictability of Hydrometeorological Flood Events Using Radar Rainfall Nowcasting

2006 ◽  
Vol 7 (4) ◽  
pp. 660-677 ◽  
Author(s):  
Enrique R. Vivoni ◽  
Dara Entekhabi ◽  
Rafael L. Bras ◽  
Valeriy Y. Ivanov ◽  
Matthew P. Van Horne ◽  
...  
Keyword(s):  
Lead Time ◽  
Flash Flood ◽  
Spatial Scales ◽  
Surface Characteristics ◽  
Hydrologic Model ◽  
Flood Events ◽  
Catchment Scale ◽  
Radar Rainfall ◽  
Time Operation ◽  
Forecast Lead Time

Abstract The predictability of hydrometeorological flood events is investigated through the combined use of radar nowcasting and distributed hydrologic modeling. Nowcasting of radar-derived rainfall fields can extend the lead time for issuing flood and flash flood forecasts based on a physically based hydrologic model that explicitly accounts for spatial variations in topography, surface characteristics, and meteorological forcing. Through comparisons to discharge observations at multiple gauges (at the basin outlet and interior points), flood predictability is assessed as a function of forecast lead time, catchment scale, and rainfall spatial variability in a simulated real-time operation. The forecast experiments are carried out at temporal and spatial scales relevant for operational hydrologic forecasting. Two modes for temporal coupling of the radar nowcasting and distributed hydrologic models (interpolation and extended-lead forecasting) are proposed and evaluated for flood events within a set of nested basins in Oklahoma. Comparisons of the radar-based forecasts to persistence show the advantages of utilizing radar nowcasting for predicting near-future rainfall during flood event evolution.

scholarly journals The Coupling of NSSL Warn-on-Forecast and FLASH Systems for Probabilistic Flash Flood Prediction

2020 ◽  
Vol 21 (1) ◽  
pp. 123-141
Author(s):  
Nusrat Yussouf ◽  
Katie A. Wilson ◽  
Steven M. Martinaitis ◽  
Humberto Vergara ◽  
Pamela L. Heinselman ◽  
...  
Keyword(s):  
Lead Time ◽  
Flash Flood ◽  
Spatial Scales ◽  
Initial Assessment ◽  
Flood Events ◽  
Short Term ◽  
Flood Prediction ◽  
Decision Making Processes ◽  
Operational Decision Making ◽  
Temporal And Spatial

AbstractThe goal of the National Oceanic and Atmospheric Administration’s (NOAA) Warn-on-Forecast (WoF) program is to provide frequently updating, probabilistic model guidance that will enable National Weather Service (NWS) forecasters to produce more continuous communication of hazardous weather threats (e.g., heavy rainfall, flash floods, damaging wind, large hail, and tornadoes) between the watch and warning temporal and spatial scales. To evaluate the application of this WoF concept for probabilistic short-term flash flood prediction, the 0–3-h rainfall forecasts from NOAA National Severe Storms Laboratory’s (NSSL) experimental WoF System (WoFS) were integrated as the forcing to the NWS operational hydrologic modeling core within the Flooded Locations and Simulated Hydrographs (FLASH) system. Initial assessment of the potential impacts of probabilistic short-term flash flood forecasts from this coupled atmosphere–hydrology (WoFS-FLASH) modeling system were evaluated in the 2018 Hydrometeorology Testbed Multi-Radar Multi-Sensor Hydrology experiment held in Norman, Oklahoma. During the 3-week experiment period, a total of nine NWS forecasters analyzed three retrospective flash flood events in archive mode. This study will describe specifically what information participants extracted from the WoFS-FLASH products during these three archived events, and how this type of information is expected to impact operational decision-making processes. Overall feedback from the testbed participants’ evaluations show promise for the coupled NSSL WoFS-FLASH system probabilistic flash flood model guidance to enable earlier assessment and detection of flash flood threats and to advance the current warning lead time for these events.

scholarly journals Error Propagation of Radar Rainfall Nowcasting Fields through a Fully Distributed Flood Forecasting Model

2007 ◽  
Vol 46 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Enrique R. Vivoni ◽  
Dara Entekhabi ◽  
Ross N. Hoffman
Keyword(s):  
Error Propagation ◽  
Lead Time ◽  
Hydrologic Model ◽  
Forecast Errors ◽  
Flood Forecast ◽  
Spatiotemporal Resolution ◽  
Radar Rainfall ◽  
Forecast Lead Time ◽  
Flood Simulations ◽  
Storm Characteristics

Abstract This study presents a first attempt to address the propagation of radar rainfall nowcasting errors to flood forecasts in the context of distributed hydrological simulations over a range of catchment sizes or scales. Rainfall forecasts with high spatiotemporal resolution generated from observed radar fields are used as forcing to a fully distributed hydrologic model to issue flood forecasts in a set of nested subbasins. Radar nowcasting introduces errors into the rainfall field evolution that result from spatial and temporal changes of storm features that are not captured in the forecast algorithm. The accuracy of radar rainfall and flood forecasts relative to observed radar precipitation fields and calibrated flood simulations is assessed. The study quantifies how increases in nowcasting errors with lead time result in higher flood forecast errors at the basin outlet. For small, interior basins, rainfall forecast errors can be simultaneously amplified or dampened in different flood forecast locations depending on the forecast lead time and storm characteristics. Interior differences in error propagation are shown to be effectively averaged out for larger catchment scales.

Radar-based rainfall nowcasting for flash flood hazard assessment: recent results at regional and Continental scales

2020 ◽  
Author(s):  
Marc Berenguer ◽  
Shinju Park ◽  
Daniel Sempere-Torres
Keyword(s):  
Real Time ◽  
Hazard Assessment ◽  
Flash Flood ◽  
Flood Hazard ◽  
Spatial Scales ◽  
Flash Floods ◽  
Radar Rainfall ◽  
European Projects ◽  
Rainfall Estimates ◽  
Ne Spain

<p>Radar rainfall estimates and nowcasts have been used in Catalonia (NE Spain) for real-time flash flood hazard nowcasting based on the basin-aggregated rainfall for several years. This approach has been further developed within the European Projects ERICHA (www.ericha.eu) and ANYWHERE (www.anywhere-h2020.eu), where it has been demonstrated to monitor flash floods in real time in several locations and at different spatial scales (from regional to Continental coverage).</p><p>The work summarizes the main results of the recent projects, analysing the performance of the flash flood nowcasting system. The results obtained on recent events  show the main advantages and some of the limitations of the system.</p>

scholarly journals Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model

2011 ◽  
Vol 15 (12) ◽  
pp. 3809-3827 ◽  
Author(s):  
A. Atencia ◽  
L. Mediero ◽  
M. C. Llasat ◽  
L. Garrote
Keyword(s):  
Sensitivity Analysis ◽  
Time Resolution ◽  
Heavy Rainfall ◽  
Flash Flood ◽  
Probabilistic Approach ◽  
Great Influence ◽  
Hydrologic Model ◽  
Radar Rainfall ◽  
Distributed Hydrologic Model ◽  
Correction Technique

Abstract. The performance of a hydrologic model depends on the rainfall input data, both spatially and temporally. As the spatial distribution of rainfall exerts a great influence on both runoff volumes and peak flows, the use of a distributed hydrologic model can improve the results in the case of convective rainfall in a basin where the storm area is smaller than the basin area. The aim of this study was to perform a sensitivity analysis of the rainfall time resolution on the results of a distributed hydrologic model in a flash-flood prone basin. Within such a catchment, floods are produced by heavy rainfall events with a large convective component. A second objective of the current paper is the proposal of a methodology that improves the radar rainfall estimation at a higher spatial and temporal resolution. Composite radar data from a network of three C-band radars with 6-min temporal and 2 × 2 km2 spatial resolution were used to feed the RIBS distributed hydrological model. A modification of the Window Probability Matching Method (gauge-adjustment method) was applied to four cases of heavy rainfall to improve the observed rainfall sub-estimation by computing new Z/R relationships for both convective and stratiform reflectivities. An advection correction technique based on the cross-correlation between two consecutive images was introduced to obtain several time resolutions from 1 min to 30 min. The RIBS hydrologic model was calibrated using a probabilistic approach based on a multiobjective methodology for each time resolution. A sensitivity analysis of rainfall time resolution was conducted to find the resolution that best represents the hydrological basin behaviour.

Radar rainfall estimation in the context of post-event analysis of flash-flood events

2010 ◽  
Vol 394 (1-2) ◽  
pp. 17-27 ◽  
Author(s):  
Ludovic Bouilloud ◽  
Guy Delrieu ◽  
Brice Boudevillain ◽  
Pierre-Emmanuel Kirstetter
Keyword(s):  
Flash Flood ◽  
Event Analysis ◽  
Flood Events ◽  
Rainfall Estimation ◽  
Radar Rainfall

scholarly journals Multi-scale hydrometeorological observation and modelling for flash-flood understanding

2014 ◽  
Vol 11 (2) ◽  
pp. 1871-1945 ◽  
Author(s):  
I. Braud ◽  
P.-A. Ayral ◽  
C. Bouvier ◽  
F. Branger ◽  
G. Delrieu ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Flash Flood ◽  
Spatial Scales ◽  
Regional Scale ◽  
Runoff Generation ◽  
Catchment Scale ◽  
Ungauged Catchments ◽  
The Mediterranean ◽  
Set Up ◽  
The Impact

Abstract. This paper presents a coupled observation and modelling strategy aiming at improving the understanding of processes triggering flash floods. This strategy is illustrated for the Mediterranean area using two French catchments (Gard and Ardèche) larger than 2000 km2. The approach is based on the monitoring of nested spatial scales: (1) the hillslope scale, where processes influencing the runoff generation and its concentration can be tackled; (2) the small to medium catchment scale (1–100 km2) where the impact of the network structure and of the spatial variability of rainfall, landscape and initial soil moisture can be quantified; (3) the larger scale (100–1000 km2) where the river routing and flooding processes become important. These observations are part of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) Enhanced Observation Period (EOP) and lasts four years (2012–2015). In terms of hydrological modelling the objective is to set up models at the regional scale, while addressing small and generally ungauged catchments, which is the scale of interest for flooding risk assessment. Top-down and bottom-up approaches are combined and the models are used as "hypothesis testing" tools by coupling model development with data analyses, in order to incrementally evaluate the validity of model hypotheses. The paper first presents the rationale behind the experimental set up and the instrumentation itself. Second, we discuss the associated modelling strategy. Results illustrate the potential of the approach in advancing our understanding of flash flood processes at various scales.

scholarly journals An Overview of the Performance and Operational Applications of the MRMS and FLASH Systems in Recent Significant Urban Flash Flood Events

2021 ◽  
pp. 1-29
Author(s):  
ALAN GERARD ◽  
STEVEN M. MARTINAITIS ◽  
JONATHAN J. GOURLEY ◽  
KENNETH W. HOWARD ◽  
JIAN ZHANG
Keyword(s):  
Urban Areas ◽  
Situational Awareness ◽  
Prediction Models ◽  
Flash Flood ◽  
Spatial Scales ◽  
Weather Prediction ◽  
Small Time ◽  
Severe Weather ◽  
Flood Events ◽  
The Public

AbstractThe Multi-Radar Multi-Sensor (MRMS) system is an operational, state-of-the-science hydrometeorological data analysis and nowcasting framework that combines data from multiple radar networks, satellites, surface observational systems, and numerical weather prediction models to produce a suite of real-time, decision-support products every two minutes over the contiguous United States and southern Canada. The Flooded Locations and Simulated Hydrograph (FLASH) component of the MRMS system was designed for the monitoring and prediction of flash floods across small time and spatial scales required for urban areas given their rapid hydrologic response to precipitation. Developed at the National Severe Storms Laboratory in collaboration with the Cooperative Institute for Mesoscale Meteorological Studies (CIMMS) and other research entities, the objective for MRMS and FLASH is to be the world’s most advanced system for severe weather and storm-scale hydrometeorology, leveraging the latest science and observation systems to produce the most accurate and reliable hydrometeorological and severe weather analyses. NWS forecasters, the public and the private sector utilize a variety of products from the MRMS and FLASH systems for hydrometeorological situational awareness and to provide warnings to the public and other users about potential impacts from flash flooding. This article will examine the performance of hydrometeorological products from MRMS and FLASH, and provide perspectives on how NWS forecasters use these products in the prediction of flash flood events with an emphasis on the urban environment.

Advances and challenges of the French operational flash flood warning system, Vigicrues Flash

2021 ◽  
Author(s):  
Julie Demargne ◽  
Catherine Fouchier ◽  
Didier Organde ◽  
Olivier Piotte ◽  
Anne Belleudy
Keyword(s):  
Hydrological Model ◽  
Flash Flood ◽  
Warning System ◽  
Hydrologic Model ◽  
Parameters Estimation ◽  
Flood Events ◽  
Time Step ◽  
Flood Warning ◽  
Flood Warning System ◽  
High Flood

<p align="justify"><span>Since March 2017, t</span><span>he French flash flood warning system, Vigicrues Flash, provides warnings for small-to-medium ungauged basins for about 10,000 municipalities to help emergency services better mitigate potential impacts of ongoing and upcoming flash flood events. Set up by the Ministry in charge of Environment, this system complements flood warnings produced by the Vigicrues procedure for French monitored rivers. Based on a discharge-threshold flood warning method called AIGA, Vigicrues Flash currently ingests radar-gauge rainfall grids at a 1-km resolution into a conceptual distributed rainfall-runoff model. Real-time peak discharge estimated on any river cell are then compared to regionalized flood quantiles (estimated with the same hydrological model). Automated warnings are issued for rivers exceeding the high flood and very high flood thresholds (defined as years of return periods) and for the associated municipalities that might be impacted. This service shares a web platform for the dissemination and communication of early warnings and hazard map displays with the APIC heavy rainfall warning service from Météo-France. </span></p><p align="justify"><span>To better anticipate flash flood events and extend the coverage of the Vigicrues Flash service, the hydrological modeling is being enhanced within the SMASH </span><span>(</span><span>S</span><span>patially-distributed </span><span>M</span><span>odelling and </span><span>AS</span><span>similation for </span><span>H</span><span>ydrology) </span><span>platform developed by INRAE (formerly Irstea). For the upcoming operational update of Vigicrues Flash, a simplified distributed hydrologic model is continuously run at a 15-minute time step and a 1-km resolution. It includes only 2 parameters per cell, controlling respectively a production reservoir and a transfer reservoir from the Génie Rural (GR) conceptual models. Cross-validation and regionalization of these two parameters have been improved to better account for basins spatial heterogeneities while optimizing flash flood warning performance. Evaluation results for 921 French basins on the 2007-2019 period show improvements in terms of flash flood event detection and effective warning lead time. Current developments aim to integrate a cell-to-cell routing component and improve parameters estimation at the national scale with the variational calibration schemes recently developed on the SMASH platform by Jay-Allemand et al. (2020). Challenges of including high-resolution precipitation nowcasts and accounting for the hydrometeorological uncertainties via data assimilation and ensemble forecasting are also discussed based on ongoing SMASH research.</span></p><p align="justify"> </p><p align="justify">Jay-Allemand, M., Javelle, P., Gejadze, I., Arnaud, P., Malaterre, P.-O., Fine, J.-A., and Organde, D.: On the potential of variational calibration for a fully distributed hydrological model: application on a Mediterranean catchment, Hydrol. Earth Syst. Sci., 24, 5519–5538, https://doi.org/10.5194/hess-24-5519-2020, 2020.</p>

scholarly journals Multi-scale hydrometeorological observation and modelling for flash flood understanding

2014 ◽  
Vol 18 (9) ◽  
pp. 3733-3761 ◽  
Author(s):  
I. Braud ◽  
P.-A. Ayral ◽  
C. Bouvier ◽  
F. Branger ◽  
G. Delrieu ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Flash Flood ◽  
Spatial Scales ◽  
Regional Scale ◽  
Runoff Generation ◽  
Catchment Scale ◽  
Ungauged Catchments ◽  
The Mediterranean ◽  
Set Up ◽  
The Impact

Abstract. This paper presents a coupled observation and modelling strategy aiming at improving the understanding of processes triggering flash floods. This strategy is illustrated for the Mediterranean area using two French catchments (Gard and Ardèche) larger than 2000 km2. The approach is based on the monitoring of nested spatial scales: (1) the hillslope scale, where processes influencing the runoff generation and its concentration can be tackled; (2) the small to medium catchment scale (1–100 km2), where the impact of the network structure and of the spatial variability of rainfall, landscape and initial soil moisture can be quantified; (3) the larger scale (100–1000 km2), where the river routing and flooding processes become important. These observations are part of the HyMeX (HYdrological cycle in the Mediterranean EXperiment) enhanced observation period (EOP), which will last 4 years (2012–2015). In terms of hydrological modelling, the objective is to set up regional-scale models, while addressing small and generally ungauged catchments, which represent the scale of interest for flood risk assessment. Top-down and bottom-up approaches are combined and the models are used as "hypothesis testing" tools by coupling model development with data analyses in order to incrementally evaluate the validity of model hypotheses. The paper first presents the rationale behind the experimental set-up and the instrumentation itself. Second, we discuss the associated modelling strategy. Results illustrate the potential of the approach in advancing our understanding of flash flood processes on various scales.

scholarly journals Characterization of physically based hydrologic model behaviour with temporal sensitivity analysis for flash floods in Mediterranean catchments

2013 ◽  
Vol 10 (1) ◽  
pp. 1375-1422
Author(s):  
P. A. Garambois ◽  
H. Roux ◽  
K. Larnier ◽  
W. Castaings ◽  
D. Dartus
Keyword(s):  
Sensitivity Analysis ◽  
Flash Flood ◽  
Soil Depth ◽  
Flash Floods ◽  
Hydrologic Model ◽  
Valuable Insight ◽  
Model Output ◽  
Flood Events ◽  
Extreme Flood ◽  
Physically Based

Abstract. This paper presents a detailed analysis of 10 flash flood events in the Mediterranean region using the distributed hydrological model MARINE. Characterizing catchment's response during flash flood events may provide a new and valuable insight into the processes involved for extreme flood response and their dependency on catchment properties and flood severity. The main objective of this study is to analyze hydrologic model sensitivity in the case of flash floods with a new approach in hydrology, allowing model outputs variance decomposition for temporal patterns of parameter sensitivity analysis. Such approaches enable ranking of uncertainty sources for non-linear and non-monotonic mappings with a low computational cost. This study uses hydrologic model and sensitivity analysis as learning tools to derive temporal sensitivity analysis with a variance based method in the case of 10 flash floods that occurred in the French Pyrenees and Cévennes foothills. This constitutes a huge dataset given the scarcity of data about flash flood events. With Nash performances above 0.73 on average for this extended set of validation events, the five sensitive parameters of MARINE distributed physically based model are analyzed. This contribution shows that soil depth explains more than 80% of model output variance when most hydrographs are peaking. Moreover the lateral subsurface transfer is responsible for 80% of model variance for some catchment-flood events' hydrographs during slow declining limbs. The unexplained variance of model output representing interactions between parameters reveals to be very low during modeled flood peaks and informs that model parsimonious parameterization is appropriate to tackle the problem of flash floods. Interactions observed after model initialization or rainfall intensity peaks incite to improve water partition representation between flow components and initialization itself. This paper gives a practical framework for application of this method to other models, landscapes and climatic conditions, potentially helping to improve processes understanding and representation.

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