Modal morphing on meteorological radar data for rainfall pattern analysis

Owing to their short duration and high intensity, flash floods are among the most devastating natural disasters in metropolises. The existing warning tools—flood potential maps and two-dimensional numerical models—are disadvantaged by time-consuming computation and complex model calibration. This study develops a data-driven, probabilistic rainfall-inundation model for flash-flood warnings. Applying a modified support vector machine (SVM) to limited flood information, the model provides probabilistic outputs, which are superior to the Boolean functions of the traditional rainfall-flood threshold method. The probabilistic SVM-based model is based on a data preprocessing framework that identifies the expected durations of hazardous rainfalls via rainfall pattern analysis, ensuring satisfactory training data, and optimal rainfall thresholds for validating the input/output data. The proposed model was implemented in 12 flash-flooded districts of the Xindian River. It was found that (1) hydrological rainfall pattern analysis improves the hazardous event identification (used for configuring the input layer of the SVM); (2) brief hazardous events are more critical than longer-lasting events; and (3) the SVM model exports the probability of flash flooding 1 to 3 h in advance.

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Towards the Next Generation Operational Meteorological Radar

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-20-0067.1 ◽

2021 ◽

pp. 1-69

Author(s):

Mark Weber ◽

Kurt Hondl ◽

Nusrat Yussouf ◽

Youngsun Jung ◽

Derek Stratman ◽

...

Keyword(s):

Flash Flood ◽

Beam Steering ◽

Radar Data ◽

Severe Weather ◽

Flood Warning ◽

Radar Network ◽

Additional Improvement ◽

Meteorological Radar ◽

Low Altitude ◽

Assess Data Quality

AbstractThis article summarizes research and risk reduction that will inform acquisition decisions regarding NOAA’s future national operational weather radar network. A key alternative being evaluated is polarimetric phased-array radar (PAR). Research indicates PAR can plausibly achieve fast, adaptive volumetric scanning, with associated benefits for severe-weather warning performance. We assess these benefits using storm observations and analyses, observing system simulation experiments, and real radar-data assimilation studies. Changes in the number and/or locations of radars in the future network could improve coverage at low altitude. Analysis of benefits that might be so realized indicates the possibility for additional improvement in severe-weather and flash-flood warning performance, with associated reduction in casualties. Simulations are used to evaluate techniques for rapid volumetric scanning and assess data quality characteristics of PAR. Finally, we describe progress in developing methods to compensate for polarimetric variable estimate biases introduced by electronic beam-steering. A research-to-operations (R2O) strategy for the PAR alternative for the WSR-88D replacement network is presented.

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Influences of hydrological and hydrogeological conditions on debris flows in peri-vesuvian hillslopes

Natural Hazards and Earth System Science ◽

10.5194/nhess-2-27-2002 ◽

2002 ◽

Vol 2 (1/2) ◽

pp. 27-35 ◽

Cited By ~ 24

Author(s):

P. De Vita ◽

V. Piscopo

Keyword(s):

Hydraulic Conductivity ◽

Debris Flows ◽

Pattern Analysis ◽

Rainfall Pattern ◽

Soil Stability ◽

Strong Variation ◽

Hydraulic Flow ◽

Water Tables ◽

The Stability ◽

Pyroclastic Soil

Abstract. The paper illustrates some results of research carried out to assess factors triggering debris flows which involve the pyroclastic overburdens covering carbonate mountains around Vesuvius. The aims of the research were to reconstruct a relationship between rainfall and debris flow occurrence and to highlight empirical hydrological thresholds through rainfall pattern analysis. The research was also aimed at investigating hydrogeological features of a pyroclastic cover-carbonate bedrock system to analyse factors inducing temporary hydraulic flow, critical for pyroclastic soil stability. The results of research are the following: i) rainfall pattern highlights empirical hydrological thresholds that differentiate the Lattari and Salerno Mountains from the Sarno Mountains; ii) in some sample areas of the Sarno Mountains close to the trigger zones of the landslides of May 1998 strong variation in hydraulic conductivity has been found in the first few meters below the surface; iii) these permeability variations would seem to justify temporary perched water tables that might affect the stability of the pyroclastic mantle.

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