scholarly journals Comparison of accuracy of forecasting methods of convective precipitation

2018 ◽  
Vol 210 ◽  
pp. 04035
Author(s):  
David Šaur ◽  
Lukáš Pavlík
Keyword(s):  
Selection Criteria ◽  
Statistical Prediction ◽  
Convective Precipitation ◽  
Quantitative Prediction ◽  
Flood Events ◽  
Forecasting Methods ◽  
X Band ◽  
Meteorological Radar ◽  
Accuracy Increase ◽  
Prediction Parameters

This article is focused on the comparison of the accuracy of quantitative, numerical, statistical and nowcasting forecasting methods of convective precipitation including three flood events that occurred in the Zlin region in the years 2015 - 2017. Quantitative prediction is applied to the Algorithm of Storm Prediction for outputs “The probability of convective precipitation and The statistical forecast of convective precipitation”. The quantitative prediction of the probability of convective precipitation is primarily compared with the precipitation forecasts calculated by publicly available NWP models; secondary to statistical and nowcasting predictions. The statistical prediction is computed on the historical selection criteria and is intended as a complementary prediction to the first algorithm output. The nowcasting prediction operates with radar precipitation measurements, specifically with X-band meteorological radar outputs of the Zlín Region. Compared forecasting methods are used for the purposes of verification and configuration prediction parameters for accuracy increase of algorithm outputs.

scholarly journals Estimation of convective precipitation: the meteorological radar versus an automatic rain gauge network

2005 ◽  
Vol 2 ◽  
pp. 103-109 ◽  
Author(s):  
M. C. Llasat ◽  
T. Rigo ◽  
M. Ceperuelo ◽  
A. Barrera
Keyword(s):  
Rain Rate ◽  
Rain Gauge ◽  
Space Distribution ◽  
Convective Precipitation ◽  
Precipitation Event ◽  
Convective Rainfall ◽  
Rainfall Events ◽  
Rain Gauges ◽  
Meteorological Radar ◽  
Rain Gauge Network

Abstract. The estimation of convective precipitation and its contribution to total precipitation is an important issue both in hydrometeorology and radio links. The greatest part of this kind of precipitation is related with high intensity values that can produce floods and/or damage and disturb radio propagation. This contribution proposes two approaches for the estimation of convective precipitation, using the β parameter that is related with the greater or lesser convective character of the precipitation event, and its time and space distribution throughout the entire series of the samples. The first approach was applied to 126 rain gauges of the Automatic System of Hydrologic Information of the Internal Basins of Catalonia (NE Spain). Data are series of 5-min rain rate, for the period 1996-2002, and a long series of 1-min rain rate starting in 1927. Rainfall events were classified according to this parameter. The second approach involved using information obtained by the meteorological radar located near Barcelona. A modified version of the SCIT method for the 3-D analysis and a combination of different methods for the 2-D analysis were applied. Convective rainfall charts and β charts were reported. Results obtained by the rain gauge network and by the radar were compared. The application of the β parameter to improve the rainfall regionalisation was demonstrated.

scholarly journals Statistical prediction of seasonal cyclonic activity over North Indian Ocean

MAUSAM ◽  
2021 ◽  
Vol 63 (1) ◽  
pp. 17-28
Author(s):  
S. BALACHANDRAN ◽  
B. GEETHA
Keyword(s):  
Indian Ocean ◽  
Regression Model ◽  
North Indian Ocean ◽  
Statistical Prediction ◽  
Quantitative Prediction ◽  
Climate Indices ◽  
Bias Error ◽  
Northeast Monsoon ◽  
Cyclonic Activity ◽  
The North

The Northeast monsoon season of October to December (OND) is the primary season of cyclonic activity over the North Indian Ocean (NIO). The mean number of days of cyclonic activity over NIO during this season is about 20 days. In the present study, statistical prediction for seasonal cyclonic activity over the North Indian Ocean during the cyclone season of October to December is attempted using well known climate indices and regional circulation features during the recent 30 years of 1971-2000.Potential predictors are identified using correlation analysis and optimum numbers of predictors are chosen using screening regression technique. A qualitative prediction for number of Cyclonic Disturbance (CD) days is attempted by analysing the conditional means of the number of CD days during OND over NIO for different intervals of each predictor based on the 30 year data of 1971-2000. Predictions and their validations for the subsequent test period of 2001 to 2009, based on this scheme, are discussed. An attempt for quantitative prediction is also made by developing a multiple regression model for prediction of number of CD days over the NIO during OND using the same predictors. The regression model accounts for 70% of the inter annual variance. The root mean square error of estimate is 5 days and the bias error is 0.36 days. The regression model is cross validated by Jackknife method for each individual year using the data of 29 years from the sample excluding the year under consideration. The model is also tested for independent dataset for the years 2001 to 2009. Salient features of the model performance are discussed.

Comparison of Disdrometer and X-Band Mobile Radar Observations in Convective Precipitation

2014 ◽  
Vol 142 (7) ◽  
pp. 2414-2435 ◽  
Author(s):  
Evan A. Kalina ◽  
Katja Friedrich ◽  
Scott M. Ellis ◽  
Donald W. Burgess
Keyword(s):  
Attenuation Correction ◽  
Numerical Models ◽  
Radar Data ◽  
Convective Precipitation ◽  
Radar Signal ◽  
Squall Line ◽  
Drop Shape ◽  
X Band ◽  
Signal Quality Index ◽  
Differential Reflectivity

Abstract Microphysical data from thunderstorms are sparse, yet they are essential to validate microphysical schemes in numerical models. Mobile, dual-polarization, X-band radars are capable of providing a wealth of data that include radar reflectivity, drop shape, and hydrometeor type. However, X-band radars suffer from beam attenuation in heavy rainfall and hail, which can be partially corrected with attenuation correction schemes. In this research, the authors compare surface disdrometer observations to results from a differential phase-based attenuation correction scheme. This scheme is applied to data recorded by the National Oceanic and Atmospheric Administration (NOAA) X-band dual-polarized (NOXP) mobile radar, which was deployed during the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2). Results are presented from five supercell thunderstorms and one squall line (183 min of data). The median disagreement (radar–disdrometer) in attenuation-corrected reflectivity Z and differential reflectivity ZDR is just 1.0 and 0.19 dB, respectively. However, two data subsets reveal much larger discrepancies in Z (ZDR): 5.8 (1.6) dB in a hailstorm and −13 (−0.61) dB when the radar signal quality index (SQI) is less than 0.8. The discrepancies are much smaller when disdrometer and S-band Weather Surveillance Radar-1988 Doppler (WSR-88D) Z are compared, with differences of −1.5 dB (hailstorm) and −0.66 dB (NOXP SQI < 0.8). A comparison of the hydrometeor type retrieved from disdrometer and NOXP radar data is also presented, in which the same class is assigned 63% of the time.

scholarly journals Trends in flash flood events versus convective precipitation in the Mediterranean region: The case of Catalonia

2016 ◽  
Vol 541 ◽  
pp. 24-37 ◽  
Author(s):  
Maria Carmen Llasat ◽  
Raul Marcos ◽  
Marco Turco ◽  
Joan Gilabert ◽  
Montserrat Llasat-Botija
Keyword(s):  
Mediterranean Region ◽  
Flash Flood ◽  
Convective Precipitation ◽  
Flood Events ◽  
The Mediterranean

scholarly journals Forecasting in Crisis Management Organization

Upravlenie ◽  
2016 ◽  
Vol 4 (4) ◽  
pp. 91-98
Author(s):  
Лоханова ◽  
Valyentina Lokhanova
Keyword(s):  
Crisis Management ◽  
Selection Criteria ◽  
Scientific School ◽  
Corporate Management ◽  
Business Sector ◽  
Advantages And Disadvantages ◽  
Russian Economy ◽  
Forecasting Methods ◽  
Depressed State ◽  
Probability Of Bankruptcy

The relevance of scientific research in the field of crisis management due to the depressed state of the Russian economy, including its business sector. One of the important directions of the scientific school of the Department of corporate management is forecasting the development of the organization in crisis. The article defines the essence of anti-crisis forecasting, its objective, stages and influencing factors. Special attention is given to forecasting methods, their classification, selection criteria. The contribution of famous Russian and foreign scientists to the theory of forecasting of bankruptcy of the organization, a comparative analysis of the advantages and disadvantages of different methods of forecasting. The list of critical indicators of the probability of bankruptcy.

scholarly journals Characterization of a Mediterranean flash flood event using rain gauges, radar, GIS and lightning data

2008 ◽  
Vol 17 ◽  
pp. 35-41 ◽  
Author(s):  
M. Barnolas ◽  
A. Atencia ◽  
M. C. Llasat ◽  
T. Rigo
Keyword(s):  
Flash Flood ◽  
Radar Data ◽  
Convective Precipitation ◽  
Flood Event ◽  
Flood Events ◽  
Rain Gauges ◽  
Radar Echoes ◽  
Spatial Coverage ◽  
Ephemeral Rivers ◽  
Accumulated Rainfall

Abstract. Flash flood events are very common in Catalonia, generating a high impact on society, including losses in life almost every year. They are produced by the overflowing of ephemeral rivers in narrow and steep basins close to the sea. This kind of floods is associated with convective events producing high rainfall intensities. The aim of the present study is to analyse the 12–14 September 2006 flash flood event within the framework of the characteristics of flood events in the Internal Basins of Catalonia (IBC). To achieve this purpose all flood events occurred between 1996 and 2005 have been analysed. Rainfall and radar data have been introduced into a GIS, and a classification of the events has been done. A distinction of episodes has been made considering the spatial coverage of accumulated rainfall in 24 h, and the degree of the convective precipitation registered. The study case can be considered as a highly convective one, with rainfalls covering all the IBC on the 13th of September. In that day 215.9 mm/24 h were recorded with maximum intensities above 130 mm/h. A complete meteorological study of this event is also presented. In addition, as this is an episode with a high lightning activity it has been chosen to be studied into the framework of the FLASH project. In this way, a comparison between this information and raingauge data has been developed. All with the goal in mind of finding a relation between lightning density, radar echoes and amounts of precipitation. Furthermore, these studies improve our knowledge about thunderstorms systems.

scholarly journals Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam

2016 ◽  
Vol 16 (4) ◽  
pp. 941-961 ◽  
Author(s):  
Heiko Apel ◽  
Oriol Martínez Trepat ◽  
Nguyen Nghia Hung ◽  
Do Thi Chinh ◽  
Bruno Merz ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Urban Areas ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Mekong Delta ◽  
Water Levels ◽  
Convective Precipitation ◽  
Processing Unit ◽  
Flood Events ◽  
Can Tho City

Abstract. Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either a fluvial or pluvial flood hazard, studies of a combined fluvial and pluvial flood hazard are hardly available. Thus this study aims to analyse a fluvial and a pluvial flood hazard individually, but also to develop a method for the analysis of a combined pluvial and fluvial flood hazard. This combined fluvial–pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as an example. In this tropical environment the annual monsoon triggered floods of the Mekong River, which can coincide with heavy local convective precipitation events, causing both fluvial and pluvial flooding at the same time. The fluvial flood hazard was estimated with a copula-based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. The pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data and a stochastic rainstorm generator. Inundation for all flood scenarios was simulated by a 2-dimensional hydrodynamic model implemented on a Graphics Processing Unit (GPU) for time-efficient flood propagation modelling. The combined fluvial–pluvial flood scenarios were derived by adding rainstorms to the fluvial flood events during the highest fluvial water levels. The probabilities of occurrence of the combined events were determined assuming independence of the two flood types and taking the seasonality and probability of coincidence into account. All hazards – fluvial, pluvial and combined – were accompanied by an uncertainty estimation taking into account the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by percentile maps. The results are critically discussed and their usage in flood risk management are outlined.

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