scholarly journals Wind gust estimation for Mid-European winter storms: towards a probabilistic view

2012 ◽  
Vol 64 (1) ◽  
pp. 17471 ◽  
Author(s):  
Kai Born ◽  
Patrick Ludwig ◽  
Joaquim G. Pinto
Keyword(s):  
Wind Gust ◽  
Winter Storms

scholarly journals Modelling winter storm impacts on insured claim ratios of residential buildings in German administrative districts

2021 ◽  
Author(s):  
Andreas Trojand ◽  
Nico Becker ◽  
Henning Rust
Keyword(s):  
Urban Areas ◽  
Linear Models ◽  
Mean Squared Error ◽  
Residential Buildings ◽  
Daily Maximum ◽  
Wind Gust ◽  
Loss Ratio ◽  
Winter Storms ◽  
Wind Speeds ◽  
Link Functions

<p>Severe winter storms are one of the most damaging natural hazards for European residential buildings. Previous studies mainly focused on the loss ratio (loss value / total insured sum) as a monetary value for damages. In this study the focus is on the claim ratio (number of claims / number of contracts), which is derived from a storm loss dataset provided by the German Insurance Association. Due to its magnitude, the claim ratio might be a more intuitive parameter for the use in impact-based warnings than the loss ratio.</p><p>In a first step, loss ratios and claim ratios in German administrative districts are compared to investigate differences and similarities between the two variables. While there is no significant change in the ratio between claim ratio and loss ratio with increasing wind speeds, a tendency for lower loss ratios in urban areas can be confirmed.</p><p>In a second step, a generalized linear model for daily claim ratios is developed using daily maximum wind gust (ERA5) and different non-meteorological indicators for vulnerability and exposure as predictor variables. The non-meteorological predictors are derived from the Census 2011. They include information about the district-average construction years, the number of apartments per buildings and others to get a better understanding of these factors concerning the number of buildings affected by windstorms. The modelling procedure is divided into two steps. First, a logistic regression model is used to model the probabilty claim ratios larger than zero. Second, generalized linear models with different link functions are compared regarding their ability to predict claim ratios larger than zero. In a cross-validation setting a criteria for model selection is implemented and the models of both steps are verified. Both steps show an improvement over the climatological forecast and in both cases the addition of data for vulnerability and exposure leads to in decrease of the mean squared error. </p>

scholarly journals Wintersturmschäden im Schweizer Wald von 1865 bis 2014

2015 ◽  
Vol 166 (3) ◽  
pp. 184-190 ◽  
Author(s):  
Tilo Usbeck
Keyword(s):  
Present Article ◽  
Forest Area ◽  
Wind Gust ◽  
Turn Of The Millennium ◽  
Storm Events ◽  
Winter Storm ◽  
Winter Storms ◽  
Growing Stock ◽  
The Past ◽  
Gust Speed

Forest damages from winter storms in Switzerland from 1865 to 2014 Winter storms cause the most catastrophic damages in Swiss forests. The present article analyses how these storm damages correspond with wind gust speed, growing stock and forest area, in regard to the whole country and individual cantons, and from 1865 to 2014. During the study period, 26 storm events each totalling a volume of at least 70,000 m3 damaged wood were registered. Winter storm damages were highly variable regarding absolute numbers (volume) and portions per area (m3 per ha) and per growing stock (%). In the past 150 years, the cantons Nidwalden, Freiburg, Aargau, Zurich and Zug were hit most often by storm events, with damages ranging per event in average from 2.2 m3 per ha (Zurich) to 3.1 m3 per ha (Nidwalden). At the turn of the millennium, not only the greatest damages occurred but also growing stock peaked as well did the wind gust speeds.

scholarly journals Comparison of storm damage functions and their performance

2015 ◽  
Vol 15 (4) ◽  
pp. 769-788 ◽  
Author(s):  
B. F. Prahl ◽  
D. Rybski ◽  
O. Burghoff ◽  
J. P. Kropp
Keyword(s):  
Probabilistic Models ◽  
Deterministic Model ◽  
Forecast Accuracy ◽  
Reanalysis Data ◽  
Skewed Distribution ◽  
Wind Gust ◽  
Storm Damage ◽  
Damage Functions ◽  
Winter Storms ◽  
Coefficients Of Variation

Abstract. Winter storms are the most costly natural hazard for European residential property. We compare four distinct storm damage functions with respect to their forecast accuracy and variability, with particular regard to the most severe winter storms. The analysis focuses on daily loss estimates under differing spatial aggregation, ranging from district to country level. We discuss the broad and heavily skewed distribution of insured losses posing difficulties for both the calibration and the evaluation of damage functions. From theoretical considerations, we provide a synthesis between the frequently discussed cubic wind–damage relationship and recent studies that report much steeper damage functions for European winter storms. The performance of the storm loss models is evaluated for two sources of wind gust data, direct observations by the German Weather Service and ERA-Interim reanalysis data. While the choice of gust data has little impact on the evaluation of German storm loss, spatially resolved coefficients of variation reveal dependence between model and data choice. The comparison shows that the probabilistic models by Heneka et al. (2006) and Prahl et al. (2012) both provide accurate loss predictions for moderate to extreme losses, with generally small coefficients of variation. We favour the latter model in terms of model applicability. Application of the versatile deterministic model by Klawa and Ulbrich (2003) should be restricted to extreme loss, for which it shows the least bias and errors comparable to the probabilistic model by Prahl et al. (2012).

scholarly journals 13 Years of Storms: An Analysis of the Effects of Storms on Lake Physics on the Atlantic Fringe of Europe

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 318 ◽  
Author(s):  
Mikkel René Andersen ◽  
Elvira de Eyto ◽  
Mary Dillane ◽  
Russell Poole ◽  
Eleanor Jennings
Keyword(s):  
Water Column ◽  
Western Europe ◽  
Thermal Structure ◽  
Winter Storms ◽  
Water Column Stability ◽  
Physical Conditions ◽  
Order Of Magnitude ◽  
Storm Frequency ◽  
Summer Storm ◽  
Lake Physics

While winter storms are generally common in western Europe, the rarer summer storms may result in more pronounced impacts on lake physics. Using long-term, high frequency datasets of weather and lake thermal structure from the west of Ireland (2005 to 2017), we quantified the effects of storms on the physical conditions in a monomictic, deep lake close to the Atlantic Ocean. We analysed a total of 227 storms during the stratified (May to September, n = 51) and non-stratified (November to March, n = 176) periods. In winter, as might be expected, changes were distributed over the entire water column, whereas in summer, when the lake was stratified, storms only impacted the smaller volume above the thermocline. During an average summer (May–September) storm, the lake number dropped by an order of magnitude, the thermocline deepened by an average of 2.8 m, water column stability decreased by an average of 60.4 j m−2 and the epilimnion temperature decreased by a factor of five compared to the average change in winter (0.5 °C vs. 0.1 °C). Projected increases in summer storm frequency will have important implications for lake physics and biological pathways.

scholarly journals Northern Ireland's longstanding record wind gust is almost certainly incorrect

Weather ◽  
2019 ◽  
Vol 75 (1) ◽  
pp. 8-13
Author(s):  
Lucy Aylott ◽  
Stephen Burt ◽  
Mark Saunders
Keyword(s):  
Wind Gust

scholarly journals A geostatistical extreme-value framework for fast simulation of natural hazard events

2016 ◽  
Vol 472 (2189) ◽  
pp. 20150855 ◽  
Author(s):  
Benjamin D. Youngman ◽  
David B. Stephenson
Keyword(s):  
Natural Hazard ◽  
Computational Cost ◽  
Additive Model ◽  
Simulation Method ◽  
Value Theory ◽  
Extreme Value ◽  
Wind Gust ◽  
Continuous Space ◽  
Statistical Framework ◽  
Distribution Parameters

We develop a statistical framework for simulating natural hazard events that combines extreme value theory and geostatistics. Robust generalized additive model forms represent generalized Pareto marginal distribution parameters while a Student’s t -process captures spatial dependence and gives a continuous-space framework for natural hazard event simulations. Efficiency of the simulation method allows many years of data (typically over 10 000) to be obtained at relatively little computational cost. This makes the model viable for forming the hazard module of a catastrophe model. We illustrate the framework by simulating maximum wind gusts for European windstorms, which are found to have realistic marginal and spatial properties, and validate well against wind gust measurements.

scholarly journals Dynamics of Cloud-Top Generating Cells in Winter Cyclones. Part I: Idealized Simulations in the Context of Field Observations

2016 ◽  
Vol 73 (4) ◽  
pp. 1507-1527 ◽  
Author(s):  
Jason M. Keeler ◽  
Brian F. Jewett ◽  
Robert M. Rauber ◽  
Greg M. McFarquhar ◽  
Roy M. Rasmussen ◽  
...  
Keyword(s):  
Vertical Velocity ◽  
Radiative Forcing ◽  
Initial Conditions ◽  
Vertical Wind Shear ◽  
Weather Research And Forecasting ◽  
Velocity Spectrum ◽  
Latent Heating ◽  
Heating Rates ◽  
Winter Storms ◽  
Radiation Parameterizations

Abstract This paper assesses the influence of radiative forcing and latent heating on the development and maintenance of cloud-top generating cells (GCs) in high-resolution idealized Weather Research and Forecasting Model simulations with initial conditions representative of the vertical structure of a cyclone observed during the Profiling of Winter Storms campaign. Simulated GC kinematics, structure, and ice mass are shown to compare well quantitatively with Wyoming Cloud Radar, cloud probe, and other observations. Sensitivity to radiative forcing was assessed in simulations with longwave-only (nighttime), longwave-and-shortwave (daytime), and no-radiation parameterizations. The domain-averaged longwave cooling rate exceeded 0.50 K h−1 near cloud top, with maxima greater than 2.00 K h−1 atop GCs. Shortwave warming was weaker by comparison, with domain-averaged values of 0.10–0.20 K h−1 and maxima of 0.50 K h−1 atop GCs. The stabilizing influence of cloud-top shortwave warming was evident in the daytime simulation’s vertical velocity spectrum, with 1% of the updrafts in the 6.0–8.0-km layer exceeding 1.20 m s−1, compared to 1.80 m s−1 for the nighttime simulation. GCs regenerate in simulations with radiative forcing after the initial instability is released but do not persist when radiation is not parameterized, demonstrating that radiative forcing is critical to GC maintenance under the thermodynamic and vertical wind shear conditions in this cyclone. GCs are characterized by high ice supersaturation (RHice > 150%) and latent heating rates frequently in excess of 2.00 K h−1 collocated with vertical velocity maxima. Ice precipitation mixing ratio maxima of greater than 0.15 g kg−1 were common within GCs in the daytime and nighttime simulations.

scholarly journals 1. On the Nature and Character of European Winter Storms, with the best means of giving Warning of their Approach

1869 ◽  
Vol 6 ◽  
pp. 140-145
Author(s):  
R. Russell
Keyword(s):  
The Self ◽  
Convex Side ◽  
Winter Storms ◽  
Orkney Islands ◽  
Round Numbers ◽  
North And South

The object of this paper was to show the true character of storms, illustrated by those of 2d, 3d, and 4th December 1863. It was pointed out that the mode usually adopted of laying down the isobarometric lines was calculated to present an erroneous view of their figure or form. The laying down representative lines in round numbers of 5 millemetres in each, or in two-tenths of an inch of barometric readings, lead deceptively to the conclusion that the areas of least pressure were circular or elliptical.It was then shown that the lines of equal pressures were ribbed into the latitudinal line of minimum barometer, which was usually found running north and south, sometimes nearly straight, but often curved, with its convex side towards the east. The minimum line of barometer was easily fixed by consulting the self-registering barometers. The minimum line of barometer was shown to have been on the meridian of London at 8 a.m. of the 3d December, and apparently nearly straight from Algiers to the Orkney Islands.

scholarly journals Evaluating the accuracy of C- and X-band weather radars and their application for stream flow simulation

2012 ◽  
Vol 15 (4) ◽  
pp. 1121-1136 ◽  
Author(s):  
N. K. Shrestha ◽  
T. Goormans ◽  
P. Willems
Keyword(s):  
Conceptual Model ◽  
Stream Flow ◽  
Flow Simulation ◽  
Winter Storms ◽  
Weather Radars ◽  
X Band ◽  
Rainfall Estimates

This paper investigates the accuracy of rainfall estimates from C- and X-band weather radars and their application for stream flow simulation. Different adjustment procedures are applied to raw radar estimates using gauge readings from a network of 12 raingauges. The stream flow is simulated for the 48.17 km2 Molenbeek/Parkbeek catchment located in the Flemish region of Belgium based on a lumped conceptual model. Results showed that raw radar estimates can be greatly improved using adjustment procedures. The gauge-radar residuals however, remain large even after adjustments. The adjusted X-band radar estimates are observed to be better estimates than corresponding C-band estimates. Their application for stream flow simulation showed that raingauges and radars can simulate spatially more uniform winter storms with almost the same accuracy, whereas differences are more evident on summer events.

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