scholarly journals Sensitivity of Orographic Moist Convection to Landscape Variability: A Study of the Buffalo Creek, Colorado, Flash Flood Case of 1996

2001 ◽  
Vol 58 (21) ◽  
pp. 3204-3223 ◽  
Author(s):  
Fei Chen ◽  
Thomas T. Warner ◽  
Kevin Manning
Keyword(s):  
Flash Flood ◽  
Moist Convection ◽  
Buffalo Creek ◽  
Landscape Variability

Improving heavy precipitation forecasting over the western Mediterranean: Benefits of stochastic techniques for model error sampling

2021 ◽  
Author(s):  
Alejandro Hermoso ◽  
Victor Homar ◽  
Robert Plant
Keyword(s):  
Flash Flood ◽  
Numerical Models ◽  
Cloud Condensation Nuclei ◽  
Heavy Precipitation ◽  
Western Mediterranean ◽  
Cloud Formation ◽  
Stochastic Methods ◽  
Moist Convection ◽  
State Variables ◽  
Stochastic Perturbations

<p>The western Mediterranean region is frequently disrupted by heavy precipitation and flash flood episodes. Designing convection-permitting ensembles capable of accurately forecasting socially relevant aspects of these natural hazards such as timing, location, and intensity at basin scales of the order of a few hundred of squared kilometers is an extremely challenging effort. The usual forecast underdispersion prevailing at these scales motivates the research of sampling methodologies which are able to provide an adequate representation of the uncertainties in the initial atmospheric state and its time-integration by means of numerical models. This work investigates the skill of multiple techniques to sample model uncertainty in the context of heavy precipitation in the Mediterranean. The performance of multiple stochastic schemes is analyzed for a singular event occurred on 12 and 13 September 2019 in València, Murcia, and Almería (eastern Spain). This remarkable and enlightening episode caused seven casualties, the flooding of hundreds of homes and economic exceeding 425 million EUR.</p><p>Stochastic methods are compared to the popular multiphysics strategy in terms of both diversity and skill. The considered techniques include stochastic parameterization perturbation tendencies of state variables and perturbations to specific and influential parameters within the microphysics scheme (cloud condensation nuclei, fall speed factors, saturation percentage for cloud formation). The introduction of stochastic perturbations to the microphysics parameters results in an increased ensemble spread throughout the entire simulation. A conclusion of special relevance for the western Mediterranean, where local topography and deep moist convection play an essential role, is that stochastic methods significantly outperform the multiphysics-based ensemble, indicating a clear potential of stochastic parameterizations for the short-range forecast of high-impact events in the region.</p>

When the trigger of deep convection gets tricky in idealized climate simulations

2021 ◽  
Author(s):  
Dominic Matte ◽  
Jens H. Christensen ◽  
Henrik Fedderson ◽  
Rasmus A. Pederson ◽  
Henrik Vedel ◽  
...  
Keyword(s):  
Climate Models ◽  
Initial Conditions ◽  
Flash Flood ◽  
Deep Convection ◽  
Regional Climate ◽  
Lapse Rate ◽  
Moist Convection ◽  
Extreme Precipitation Events ◽  
Synoptic Conditions ◽  
Deep Moist Convection

<p><span>On the evening on July 2, 2011 a severe cloud burst occurred in the Copenhagen area. During the late afternoon deep moist convection developed over nearby Skåne (the southernmost part of Sweden) in an airstream from east-northeast. In the early evening the DMC passed over Øresund to Copenhagen, where it created a severe flash flood. Between 90 and 135 mm of precipitation in less than 2 hours was recorded ooding cellars, streets, and key roads. The deluge caused 6 billion Danish kroner in damage. Although that such extreme events are rare, the impacts on society is important and should be understood under a warmer climate. Although regional climate models have recently reached the convection permitting resolution, reproducing such events is still challenging.</span></p><p><span>Several studies suggest that extreme precipitations should increase under a future warmer climate using transient simulation or a pseudo-warming approach. It is still unclear how such event would behave under warmer or colder synoptic conditions. Using a forecast-ensemble method, but keeping a climate perspective, this study assesses the risk rising from such an event under otherwise almost identical, but warmer or colder conditions. With this set-up, we find that the development of the system that resulted in observed downpour exhibit quite a sensitivity to the initial conditions and contrary to a linear thinking, the risk of flooding is decreasing as the climate warms due to the inhibition of the CAPE by the additional lapse-rate anomalies used in this study. We therefore propose that the PGW method should be used with caution and that extreme precipitation events also in transient simulations of future climates need to be studied in detailed to address the limitations to models ability to produce those most extreme and by nature inherently rare events.</span></p>

DISTRIBUIÇÃO ESPAÇO-TEMPORAL DOS DESASTRES HIDROMETEOROLÓGICOS NA MICRORREGIÃO PLUVIOMÉTRICAMENTE HOMOGÊNEA DO LITORAL PARAIBANO

2019 ◽  
Vol 21 (2) ◽  
pp. 467-476
Author(s):  
Wanessa Janinne Eloy Da Silva ◽  
Maressa Oliveira Lopes Araújo ◽  
Marcelo De Oliveira Moura
Keyword(s):  
Flash Flood ◽  
Temporal Distribution ◽  
Heavy Rain ◽  
Emergency Situations

O presente trabalho tem por objetivo analisar a distribuição espaço-temporal dos reconhecimentos de Situação de Emergência associados à dinâmica hidrometeorológica na microrregião pluviometricamente homogênea do Litoral paraibano, durante o período de 2003 a 2016. Para isso, foram utilizados dados adquiridos no site do Ministério da Integração Nacional, encontrados na página da Secretaria Nacional de Proteção e Defesa Civil, conforme reconhecimentos disponibilizados através de portarias. Como resultados principais, constatou-se um total de 29 reconhecimentos, em que 51,7% corresponde a enchentes; 20,7% a chuvas intensas; 24,2% correspondente a enxurradas e 3,4% a inundações. Considera-se que os resultados obtidos tiveram um cunho mais descritivo, necessitando assim de estudos mais avançados sobre a temática.Palavras chave: Litoral Paraibano, desastres hidrometeorológicos, situação de emergência. ABSTRACTThe present work has for objective analyze the space-temporal distribution of the emergency situations recognizements associated to the hydrometeorological dynamic on the pluviometrically homogenius microregion of the coast of Paraíba, during the period of 2003 to 2016. For that, data were used acquired from the Ministério da Integração Nacional’s site, found on the Secretaria Nacional de Proteção e Defesa Civil’s page, conform available recognizements through ordinances. As main results, a total of 29 recognizements were found, in which 51,7% corresponds to floods; 20,7% to heavy rain; 24,2% corresponding to flash flood and 3,4% to inundations. It’s considered that the obtained results have a descriptive label, needing then advanced studies about the theme.Keywords: Coast of Paraiba, hydrometeorlogical disasters, emergency situations. RESUMENEste documento tiene como objetivo analizar la distribución espacio-temporal de los reconocimientos de situaciones de emergencia com la dinâmica hidrometeorológica em la microrregión de lluvia homogénea de la costa paraibana, de 2003 a 2016. Para este propósito, se utilizaron los datos adquiridos del sitio web del Ministerio de Salud. Integración nacional, que se encuentra en la página de la Secretaría Nacional de Protección y Defensa Civil, como agradecimientos disponibles a través de ordenanzas. Como resultados principales, hubo un total de 29 reconocimientos, de los cuales el 51.7% correspondió a inundaciones; 20.7% a fuertes lluvias; 24.2% correspondientes a enxurradas y 3.4% a inundaciones. Se considera que los resultados obtenidos tuvieron una naturaleza más descriptiva, por lo que requirieron estúdios más avanzados sobre el tema.Palabras clave: Costa de Paraiba, desastres hidrometeorológicos, situación de emergencia.

NUMERICAL SIMULATION OF BEHAVIOR OF SPHERICAL BODY WASHED AWAY BY FLASH FLOOD

2018 ◽  
Vol 74 (2) ◽  
pp. I_457-I_464
Author(s):  
Yu NISHIO ◽  
Makoto YAMAUCHI ◽  
Seiichiro IZAWA ◽  
Yu FUKUNISHI
Keyword(s):  
Numerical Simulation ◽  
Flash Flood ◽  
Spherical Body

Rotating Shallow-Water Models with Moist Convection

2018 ◽  
Author(s):  
Vladimir Zeitlin
Keyword(s):  
Baroclinic Instability ◽  
Potential Temperature ◽  
Moist Convection ◽  
Mathematical Properties ◽  
Vertical Fluxes ◽  
Equivalent Potential ◽  
Shallow Water Models ◽  
Wave Emission ◽  
Rotating Shallow Water ◽  
Convective Fluxes

It is shown how the standard RSW can be ’augmented’ to include phase transitions of water. This chapter explains how to incorporate extra (convective) vertical fluxes in the model. By using Lagrangian conservation of equivalent potential temperature condensation of the water vapour, which is otherwise a passive tracer, is included in the model and linked to convective fluxes. Simple relaxational parameterisation of condensation permits the closure of the system, and surface evaporation can be easily included. Physical and mathematical properties of thus obtained model are explained, and illustrated on the example of wave scattering on the moisture front. The model is applied to ’moist’ baroclinic instability of jets and vortices. Condensation is shown to produce a transient increase of the growth rate. Special attention is paid to the moist instabilities of hurricane-like vortices, which are shown to enhance intensification of the hurricane, increase gravity wave emission, and generate convection-coupled waves.

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