Evaluating the effects of image filtering in short‐term radar rainfall forecasting for hydrological applications

Horne, Matthew P. Van; Vivoni, Enrique R.; Entekhabi, Dara; Hoffman, Ross N.; Grassotti, Christopher

doi:10.1017/s1350482706002295

Cited by 16 publications

(20 citation statements)

References 17 publications

(30 reference statements)

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“…The first storm type (i=1 mm/h, t r =12 h) corresponds to a long-duration, lowintensity drizzle, while the second storm type (i=40 mm/h, t r =1 h) is more reflective of a short-duration, high-intensity thunderstorm. Storm types represent fall frontal storms (drizzle) and squall lines (thunderstorm) in the area (Grassotti et al, 2003;Van Horne et al, 2006). Differences in the storm properties impact the flood response as rainfall interacts in complex ways with the coupled surface-subsurface system.…”

Section: And Dry) the Top Row (A C E) Represent A Combination Of Lmentioning

confidence: 99%

Controls on runoff generation and scale-dependence in a distributed hydrologic model

Vivoni

Entekhabi

Bras

et al. 2007

Hydrol. Earth Syst. Sci.

135

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Abstract. Hydrologic response in natural catchments is controlled by a set of complex interactions between storm properties, basin characteristics and antecedent wetness conditions. This study investigates the transient runoff response to spatially-uniform storms of varying properties using a distributed model of the coupled surface-subsurface system, which treats heterogeneities in topography, soils and vegetation. We demonstrate the control that the partitioning into multiple runoff mechanisms (infiltration-excess, saturationexcess, perched return flow and groundwater exfiltration) has on nonlinearities in the rainfall-runoff transformation and its scale-dependence. Antecedent wetness imposed through a distributed water table position is varied to illustrate its effect on runoff generation. Results indicate that transitions observed in basin flood response and its nonlinear and scaledependent behavior can be explained by shifts in the surfacesubsurface partitioning. An analysis of the spatial organization of runoff production also shows that multiple mechanisms have specific catchment niches and can occur simultaneously in the basin. In addition, catchment scale plays an important role in the distribution of runoff production as basin characteristics (soils, vegetation, topography and initial wetness) are varied with basin area. For example, we illustrate how storm characteristics and antecedent wetness play an important role in the scaling properties of the catchment runoff ratio.

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Section: And Dry) the Top Row (A C E) Represent A Combination Of Lmentioning

confidence: 99%

Controls on runoff generation and scale-dependence in a distributed hydrologic model

Vivoni

Entekhabi

Bras

et al. 2007

Hydrol. Earth Syst. Sci.

135

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“…It then derives the cross correlation of successive filtered images to generate large-scale motion vectors, subsequently used to advect the original rainfall field. Forecast rainfall fields from the STNM over a number of storm events have been recently tested over the ABRFC by Van Horne et al (2006) and used for hydrological forecasting in the Baron Fork (Eldon, Oklahoma) watershed (808 km 2 ) (Vivoni et al 2006).…”

Section: Rainfall and Flood Forecasting Experimentsmentioning

confidence: 99%

“…Nowcasting is used to extrapolate rainfall between available radar images spaced at a particular lead time apart. Because this operation fills in missing radar data with a sequence of forecasts, we refer to this method as the interpolation mode [see Vivoni et al (2006) for details]. As the time between radar observations increases, the evolution of the actual rainfall field that is not captured by the nowcasting scheme leads to rainfall forecast errors as a function of lead time.…”

Section: Rainfall and Flood Forecasting Experimentsmentioning

confidence: 99%

“…A variety of advanced techniques are now available for improving the quality of rainfall input into hydrological models. These techniques include the coupling of radar rainfall estimates, radar nowcasting algorithms, and meteorological model output with rainfall-runoff forecasting models (e.g., Pereira Fo et al 1999;Benoit et al 2000;Yates et al 2000;Dolciné et al 2001;Berenguer et al 2005; Bartholmes and Todini 2005;Sharif et al 2006;Vivoni et al 2006). Advances in rainfall forecasting allow an extension of the lead time available for issuing flood warnings and can improve flood forecast accuracy because the assumption of negligible future precipitation is avoided (Collier 1991).…”

Section: Introductionmentioning

confidence: 99%

“…This differs from prior studies on the propagation of radar estimation errors (e.g., Borga 2002;Sharif et al 2002Sharif et al , 2004, because radar nowcasting fields are characterized by lead-time-dependent errors based on unpredictable storm changes. Distributed hydrological models provide an opportunity to study radar nowcasting error propagation because they are designed to capture the full information content available from weather radar over a watershed at a high spatial and temporal resolution (e.g., Pessoa et al 1993;Garrote and Bras 1995;Ivanov et al 2004b;Vivoni et al 2006). As a result, distributed models are considered to be appropriate tools to assess and validate rainfall forecast quality and to understand how errors in the rainfall field forecasts may propagate throughout the watershed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Vivoni

Entekhabi

Hoffman

2007

Journal of Applied Meteorology and Climatology

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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.

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Flash flood forecasting: What are the limits of predictability?

Collier

2007

Quart J Royal Meteoro Soc

252

158

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Flash floods may occur suddenly and be accompanied by other hazards such as landslides, mud flows, damage to infrastructure and even death. In the UK such events are comparatively rare occurring on average only once or twice per year. Warning systems must depend upon the accurate real-time provision of rainfall information, high-resolution numerical weather forecasts and the operation of hydrological model systems in addition to forecast delivery procedures not discussed in this paper. In this paper we review how flash floods are forecast considering the limitations and uncertainty involved in both the meteorological and hydrological aspects of forecasting systems. Data assimilation and the use of ensembles are both key elements across disciplines. Assessing the susceptibility of river catchments to extreme flooding is considered, and statistical methods of estimating the likelihood of extreme rainfall and floods within a changing climate are examined. Ways of constraining flash flood forecasts are noted as one way to improve forecast performance in the future.

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Evaluating the effects of image filtering in short‐term radar rainfall forecasting for hydrological applications

Abstract: Radar rainfall nowcasting at short lead times has important hydrometeorological applications in the

Cited by 16 publications

References 17 publications

Controls on runoff generation and scale-dependence in a distributed hydrologic model

Controls on runoff generation and scale-dependence in a distributed hydrologic model

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

Flash flood forecasting: What are the limits of predictability?

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