scholarly journals Daily wind gust speed probabilities over Switzerland according to three types of synoptic circulation

2002 ◽  
Vol 22 (4) ◽  
pp. 485-499 ◽  
Author(s):  
Patricia Jungo ◽  
St�phane Goyette ◽  
Martin Beniston
Keyword(s):  
Wind Gust ◽  
Synoptic Circulation ◽  
Gust Speed

scholarly journals The 21st Century Decline in Damaging European Windstorms

2016 ◽  
Author(s):  
Laura C. Dawkins ◽  
David B. Stephenson ◽  
Julia F. Lockwood ◽  
Paul E. Maisey
Keyword(s):  
21St Century ◽  
Wind Gust ◽  
Correlation Pattern ◽  
North West ◽  
Modes Of Variability ◽  
The North ◽  
Strong Positive Relationship ◽  
Resolution Model ◽  
The North Atlantic Oscillation ◽  
Gust Speed

Abstract. A decline in damaging European windstorms has led to a reduction in insured losses in the 21st century. This decline is explored by identifying a damaging windstorm characteristic and investigating how and why this characteristic has changed in recent years. This novel exploration is based on 6103 high resolution model generated historical footprints (1979–2014) representing the whole European domain. The footprint of a windstorm is defined as the maximum wind gust speed to occur at a set of spatial locations over the duration of the storm. The area of the footprint exceeding 20 ms−1 over land, A20, is shown to be a good predictor of windstorm damage. This damaging characteristic has decreased in the 21st century, due to a statistically significant decrease in the relative frequency of windstorms exceeding 20 ms−1 in north-west Europe. This is explained by a decrease in the quantiles of the footprint wind gust speed distribution above approximately 18 ms−1 at locations in this region. Much of the change in A20 is explained by the North Atlantic Oscillation (NAO). The correlation between winter total A20 and winter averaged mean sea-level pressure resembles the NAO pattern, shifted eastwards over Europe, and a strong positive relationship (correlation of 0.715) exists between winter total A20 and winter averaged NAO. The shifted correlation pattern, however, suggests that other modes of variability may also play a role in the variation in windstorm losses.

scholarly journals Hydrological and Meteorological Controls on Large Wildfire Ignition and Burned Area in Northern California during 2017–2020

Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 90
Author(s):  
Yusuke Hiraga ◽  
M. Levent Kavvas
Keyword(s):  
Vapor Pressure Deficit ◽  
Horizontal Wind ◽  
Burned Area ◽  
Wind Gust ◽  
Northern California ◽  
Horizontal Wind Speed ◽  
Spatial And Temporal Scales ◽  
Moisture Deficit ◽  
In Fire ◽  
Gust Speed

This study examined the hydrological/meteorological controls on large wildfires > 10,000 acres (40.5 km2) during 2017–2020 in Northern California at spatial and temporal scales of the target wildfires’ occurrence or growth. This study used the following simple indices for analysis: Moisture Deficit Index (MDI) computed by dividing vapor pressure deficit by soil moisture, MDIWIND computed by multiplying MDI by horizontal wind speed, and MDIGUST computed by multiplying MDI by wind gust speed. The ignition location MDIWIND and MDIGUST showed larger values on the ignition date in fire-years compared to non-fire-years for most of the target wildfires (95.8% and 91.7%, respectively). The peak timing of MDIGUST, which is to evaluate the integrated effect of dry atmosphere/soil and windy condition, coincided with the ignition date for August Complex Fire 2020, Ranch Fire 2018, Claremont-Bear Fire 2020, and Camp Fire 2018. We also found that August Complex Fire 2020, Claremont-Bear Fire 2020, and Camp Fire 2018 occurred in the areas where MDIGUST became spatially and temporally high. Further, strong relationships were found between burned area sizes of the target wildfires and MDI (R = 0.62, p = 0.002), MDIWIND (R = 0.72, p < 0.001), and MDIGUST (R = 0.68, p < 0.001). Overall, the findings in this study implied the strong effect of dry atmosphere/soil and windy conditions on recent large wildfire activities in Northern California. The findings could contribute to a more temporally and spatially detailed forecast of wildfire risks or a better understanding of wildfires’ occurrence and growth mechanisms.

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 The 21st century decline in damaging European windstorms

2016 ◽  
Vol 16 (8) ◽  
pp. 1999-2007 ◽  
Author(s):  
Laura C. Dawkins ◽  
David B. Stephenson ◽  
Julia F. Lockwood ◽  
Paul E. Maisey
Keyword(s):  
21St Century ◽  
Western Europe ◽  
Wind Gust ◽  
Correlation Pattern ◽  
Modes Of Variability ◽  
The North ◽  
Strong Positive Relationship ◽  
Resolution Model ◽  
The North Atlantic Oscillation ◽  
Gust Speed

Abstract. A decline in damaging European windstorms has led to a reduction in insured losses in the 21st century. This decline is explored by identifying a damaging windstorm characteristic and investigating how and why this characteristic has changed in recent years. This novel exploration is based on 6103 high-resolution model-generated historical footprints (1979–2014), representing the whole European domain. The footprint of a windstorm is defined as the maximum wind gust speed to occur at a set of spatial locations over the duration of the storm. The area of the footprint exceeding 20 ms−1 over land, A20, is shown to be a good predictor of windstorm damage. This damaging characteristic has decreased in the 21st century, due to a statistically significant decrease in the relative frequency of windstorms exceeding 20 ms−1 in north-western Europe, although an increase is observed in southern Europe. This is explained by a decrease in the quantiles of the footprint wind gust speed distribution above approximately 18 ms−1 at locations in this region. In addition, an increased variability in the number of windstorm events is observed in the 21st century. Much of the change in A20 is explained by the North Atlantic Oscillation (NAO). The correlation between winter total A20 and winter-averaged mean sea-level pressure resembles the NAO pattern, shifted eastwards over Europe, and a strong positive relationship (correlation of 0.715) exists between winter total A20 and winter-averaged NAO. The shifted correlation pattern, however, suggests that other modes of variability may also play a role in the variation in windstorm losses.

scholarly journals Communicating the amount of windstorm induced forest damage by the maximum wind gust speed in Finland

2019 ◽  
Vol 16 ◽  
pp. 31-37 ◽  
Author(s):  
Hannu Valta ◽  
Ilari Lehtonen ◽  
Terhi K. Laurila ◽  
Ari Venäläinen ◽  
Mikko Laapas ◽  
...  
Keyword(s):  
Time Series ◽  
Boreal Forests ◽  
Natural Disturbance ◽  
Recent Decade ◽  
Forest Damage ◽  
Wind Gust ◽  
Short Time Series ◽  
National Power ◽  
Short Time ◽  
Gust Speed

Abstract. Windstorms are natural disturbance agents in forests playing a role in natural forest regeneration. In Finland, the most severe individual windstorms have commonly damaged 2–4 million m3 of timber. In addition to financial losses caused to forest owners, windthrown trees have in many cases seriously disrupted the functionality of the national power grid. Communicating windstorm risks in duty forecasting is difficult. In this study, we aimed at developing windstorm impact estimates for forest damage in Finland to help the forecaster to improve communication of the risks of windstorms. We have compared the volume of forest damage caused by the most intense windstorms in Finland during the recent decade to the observed maximum inland wind gust speeds associated with the same windstorms. It was found out that the volume of forest damage follows approximately a power relation as a function of wind gust speed with a power of ∼10. This is a tentative estimate because of a short time series and small number of inspected windstorms. Moreover, also wind direction, location of the affected area and soil properties among other factors have an impact to the amount of damage as illustrated in our inspection. Despite the shortness of the time series, we believe that our results demonstrating the steep increase in the impacts of windstorms with an increasing windstorm intensity are valuable. However, more detailed investigations with longer time series are needed in order to more specifically communicate the windstorm risks and their impacts in boreal forests.

Probabilistic Wind Gust Forecasting Using Nonhomogeneous Gaussian Regression

2012 ◽  
Vol 140 (3) ◽  
pp. 889-897 ◽  
Author(s):  
Thordis L. Thorarinsdottir ◽  
Matthew S. Johnson
Keyword(s):  
Wind Speed ◽  
Linear Function ◽  
Location Parameter ◽  
Maximum Wind Speed ◽  
Wind Gust ◽  
Probabilistic Forecasting ◽  
Maximum Wind ◽  
Gaussian Regression ◽  
Gust Speed ◽  
Wind Speed Forecast

Abstract A joint probabilistic forecasting framework is proposed for maximum wind speed, the probability of gust, and, conditional on gust being observed, the maximum gust speed in a setting where only the maximum wind speed forecast is available. The framework employs the nonhomogeneous Gaussian regression (NGR) statistical postprocessing method with appropriately truncated Gaussian predictive distributions. For wind speed, the distribution is truncated at zero, the location parameter is a linear function of the wind speed ensemble forecast, and the scale parameter is a linear function of the ensemble variance. The gust forecasts are derived from the wind speed forecast using a gust factor, and the predictive distribution for gust speed is truncated according to its definition. The framework is applied to 48-h-ahead forecasts of wind speed over the North American Pacific Northwest obtained from the University of Washington mesoscale ensemble. The resulting density forecasts for wind speed and gust speed are calibrated and sharp, and offer substantial improvement in predictive performance over the raw ensemble or climatological reference forecasts.

scholarly journals Atmospheric Resuspension of Insoluble Radioactive Cesium Particles Found in the Difficult-to-Return Area in Fukushima

2021 ◽  
Author(s):  
PENG TANG ◽  
Kazuyuki Kita ◽  
Yasuhito Igarashi ◽  
Yukihiko Satou ◽  
Koutarou Hatanaka ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Surface Soil ◽  
Sampling Site ◽  
High Volume ◽  
Radioactive Cesium ◽  
Wind Gust ◽  
Long Distance ◽  
Relevant Evidence ◽  
First Time ◽  
Gust Speed

Abstract The deposition of insoluble radiocesium bearing microparticles (CsMPs), which were released from the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident in March 2011, has resulted in the widespread contamination of eastern Japan. Obviously, these deposited insoluble CsMPs may become the secondary contamination sources by atmospheric migration or other environmental transferring process, however, the understanding of the transport mechanism remains non-elucidation, and the relevant evidence has not been directly provided. This study, for the first time, provides the direct evidence for the resuspension of these insoluble CsMPs to the atmosphere from 1) proximity of 137Cs radioactivity and resemblance of the morphology and the elemental compositions of CsMPs in the samples of soil and aerosol derived from the same sampling site, 2) the special characteristics of the resuspended CsMPs of which the ratios of Na/Si, K/Si and/or Cs/Si were smaller than those from the initially released CsMPs collected at either long distance or near F1NPP, which can be ascribed to the slowly natural corrosion of CsMPs by the loss of the small amount of soluble contents in CsMPs and 3) high CsMPs concentration of 10 granules/gram in the surface soil of our sampling site and the observed resuspension of surface soil dust at wind gust speed higher than 4 m s-1. Specifically, fifteen single CsMPs were successfully isolated from the aerosol filters collected by unmanned high-volume air samplers at a severely polluted area in Fukushima Prefecture, about 25 km away from F1NPP, from January 2015 to September 2019. The mean diameter of these CsMPs was 1.8 ± 0.5 μm, and the average 137Cs radioactivity was 0.35 ± 0.23 Bq/granule. The contribution rate of the resuspended CsMPs to the atmospheric radiocesium was estimated from the ratio of 137Cs radioactivity of a single CsMP to that of the aerosol filter to be of 23.9 ± 15.3%. There has been no considerable decreasing trend in the annual CsMP resuspension frequency.

scholarly journals Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Tropical Cyclones ◽  
Weather Forecasting ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Level Pressure ◽  
Medium Range ◽  
Gust Speed

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.

Sign in / Sign up

Export Citation Format

Share Document