Gust Speed Research Articles

ការព្យាករល្បឿនខ្យល់គោលសម្រាប់ការគណនាអគារនៅខេត្តសៀមរាប

A basic wind speed is a very crucial parameter used for calculating the wind loads on building structures. In Cambodia, the selection of the basic wind speed for the structural design remains uncertain due to insufficient fundamental studies on the wind characteristics associated with regional climate. This article aims to predict the basic wind speed in Siem Reap, Cambodia, as a case study based on datasets received from a meteorological station. The wind speeds were measured at Siem Reap airport in the form of hourly speed and then statically converted to 3-second gust speed using Gaussian distribution transformation. The extreme value distributions, such as Gumbel and Gringorten, were utilized to analyze the extreme wind speed in accordance with a return period. The results showed that with a return period of 50 and 700 years, the basic wind speed was found to be 35 m/s and 41 m/s, respectively. These results could provide an alternative selection for the estimation of wind load for the structural design of building in Siem Reap. However, additional studies on the assessment of the existing structures under the discovered wind speeds should be conducted in order to ensure the reliability of the results.

Combining interpolated maximum wind gust speed and forest vulnerability for rapid post-storm mapping of potential forest damage areas in Finland

Abstract In Finland, wind-induced forest damage is expected to increase in the future. Demand exists for timely and precise first-hand information about the main impact area of windstorms. Locating potential damage areas quickly is essential for effective operational planning of salvage loggings, aiming to reduce monetary losses of timber and risk for secondary damage caused by insects. This study presents an approach for mapping the potential damage areas immediately after a windstorm, by using high-resolution forest vulnerability data and information on the spatial distribution of maximum wind gust speed derived from weather station observations using kriging with external drift interpolation. The new method is evaluated by analyzing damage caused by nine major windstorms of the 2010s in Finland. Our results show that including roughness length information as an auxiliary variable in the interpolation improved the results and produced wind maps with more plausible structure and better separation between forested and non-forested land areas. The forest vulnerability data were most strongly linked to damage, whilst wind gust speed had weaker results. However, for future storms with unknown damage areas, we consider maximum wind gust speed still essential for defining the main impact area, whereas forest vulnerability data could then be used for more detailed damage predictions. Further advancements of wind interpolation approaches, preferably towards higher resolution and, if possible, based on a denser and more diverse observation network, is needed to fully exploit the potential of combined wind and forest vulnerability data. Albeit we recognize multiple uncertainties, room for improvements and benefits that additional data sources would bring, our study demonstrates a simple approach for rapid mapping of potential forest wind damage areas, which could be further developed into an operational tool.

A novel framework to study community-level social and physical impacts of hurricane-induced winds through synthetic scenario analysis

Strong hurricane winds often cause severe infrastructure damage and pose social and economic consequences in coastal communities. In the context of community resilience planning, estimating such impacts can facilitate developing more risk-informed mitigation plans in the community of interest. This study presents a new framework for synthetically simulating scenario-hurricane winds using a parametric wind field model for predicting community-level building damage, direct economic loss, and social consequences. The proposed synthetic scenario approach uses historical hurricane data and adjusts its original trajectory to create synthetic change scenarios and estimates peak gust wind speed at the location of each building. In this research, a stochastic damage simulation algorithm is applied to assess the buildings’ physical damage. The algorithm assigns a damage level to each building using the corresponding damage-based fragility functions, predicted maximum gust speed at the building’s location, and a randomly generated number. The monetary loss to the building inventory due to its physical damage is determined using FEMA’s direct loss ratios and buildings’ replacement costs considering uncertainty. To assess the social impacts of the physical damage exposure, three likely post-disaster social disruptions are measured, including household dislocation, employment disruption, and school closures. The framework is demonstrated by its application to the hurricane-prone community of Onslow County, North Carolina. The novel contribution of the developed framework, aside from the introduced approach for spatial predicting hurricane-induced wind hazards, is its ability to illuminate some aspects of the social consequences of substantial physical damages to the building inventory in a coastal community due to the hurricane-induced winds. These advancements enable community planners and decision-makers to make more risk-informed decisions for improving coastal community resilience.

Climate Change Projection and Its Impacts on Building Façades in Singapore

Singapore is one of the most populous countries, and the majority of the population stays in high-rise public flats. In 2021, there were about 1.1 million public residential units, of which 79% were above 20 years old. The number of incidents of falling objects from a height has been increasing due to the aging and deterioration of buildings. The Periodic Façade Inspection (PFI) regime was enacted in 2020 to mandate façade inspections for all buildings above 13 m and exceeding 20 years old. However, the relatively new PFI regime has not considered the potential impacts of climate change on building façades. In this paper, the common root causes of façade defects that can be impacted by climate change are first identified. Based on the climate projection in Singapore to 2100, Singapore is expected to experience a higher mean temperature, a higher rainfall intensity, more extreme rainfall events, and a higher wind gust speed. Overall, these changes in the climate pattern will accelerate corrosion or degradation, material fatigue, adhesion failure, biological attack, and humidity or dampness. The impacts of climate change on vertical greeneries are also discussed. This paper provides a first insight into the key concerns to focus on for the future revision and improvement of the PFI regime to incorporate climate change impacts on façades.

Influence of Topography and the Underlying Surface of the Bohai Sea on Wind and Gust Forecasts

AbstractAccurate gust forecasts can reduce potential threats to people's lives and properties, but we need more reliable forecasting methods and models. A recent development is the meteorologically stratified gust factor (MSGF) model, which is more accurate in forecasting gusts than the previous gust factor model. The regional terrain and underlying surface both have crucial effects on the gust factor. We therefore combined observations from the China Meteorological Administration over the ocean surface and along the coast with the MSGF model to explore the influence of topography and the underlying surface on wind and gust forecasts. The regional terrain and underlying surface affected the peak gust climatologies, the mean wind speed, the mean prevailing wind direction and the gust factors. The topography and the underlying surface had different impacts in different ranges of the mean wind speed. The strong turbulence that causes changes in the gust factor under light winds is not initiated over rough underlying surfaces. When the mean wind speed is >2.5 m s−1, the underlying surface influences both the wind speed and the gust factor. A rough underlying surface stimulates stronger turbulence and increases the gust speed and gust factor, whereas a smooth underlying surface directly increases the mean wind speed and the gust speed by different magnitudes to reduce the difference between them, thus decreasing the gust factor. We evaluated the ability of the MSGF model to forecast gusts and verified a method combining the products of a numerical model and the MSGF model in gust forecasts.

Analysis of extreme wind gusts using a high-resolution Australian Regional Reanalysis

The characterisation of extreme wind gust speeds has historically relied on data from observations, while numerically modelling these events is limited due to their rarity and localised nature. However, the ongoing increase in computational power now allows extreme events to be characterised in fine-scale numerical data. Extreme gust events are examined using 24 years of 1.5 km horizontal grid reanalysis data for eastern Australia, and compared to those based on 1-minute data from station observations. We estimate return values over long periods using the generalised Pareto distribution (GPD) peaks-over-threshold approach. An automated algorithm that selects an optimal threshold at each grid point is outlined and gives similar results to an approach based on pre-fixing the shape factor value similar to what is applied in Australian building design standards. We also present a decision tree model that skillfully distinguishes between convective (i.e., thunderstorm) and synoptic (e.g., frontal system and cyclone) gust events using only hourly reanalysis data. The reanalysis shows high synoptic gust intensities and frequencies along the coast, consistent with station observations, and that synoptic-type extreme gusts are enhanced by topography (higher occurrence frequencies in mountain areas) while convective-type events are less affected. The reanalysis systematically overestimates parameterised gust activity, while compensating for this at many locations by underestimating the resolved wind speed, thus often producing gusts close to observed. With the proviso that these issues are considered, we find that the information on wind gusts provided by reanalysis data may be quite useful especially in regions with low observational network coverage.

Variations in Monthly Maximum Gust Speed at St Mary's, Isles of Scilly (UK)

AbstractLong‐term variations in maximum gust speeds have been analyzed using wind measurements recorded at St Mary's, Isles of Scilly, UK, and possible drivers of recent changes have been investigated. A rigorous homogenization procedure has been applied to the wind records to remove discontinuities mainly caused by non‐climatic changes. Trends in magnitude of the homogenized annual and monthly maximum gust speeds have been subsequently estimated. A significant (p < 0.10) decreasing trend of −0.102 m s−1/10 years is exhibited by the annual maximum gust speeds over the period 1928–2011, while a non‐significant (p > 0.10) positive trend characterizes the entire period 1928–2020 of wind measurements. A turning point has been detected in the monthly maximum gust speed series in 2012, followed by a trend reversal. Distinctive differences in the gust trend pattern have been observed among the seasons, with increasing trend in summer, and winter gust speeds exhibiting decline in 1969–2011 and strengthening since 2012. Variations in the monthly maximum gust speeds appear closely related to changes in air temperature and latitudinal pressure gradients. Furthermore, the monthly maximum gust speeds show significant correlation with the main oceanic‐atmospheric circulation patterns in the North Atlantic region. A synergistic effect among the phases of the dominant patterns of climate variability appears to explain the observed decline and recovery trends in winter gusts. Summer gust speeds show a positive correlation with the global land‐ocean temperature deviations from the corresponding 1951–1980 base period mean.

Forest disturbance and growth processes are reflected in the geographical distribution of large canopy gaps across the Brazilian Amazon

Abstract Canopy gaps are openings in the forest canopy resulting from branch fall and tree mortality events. The geographical distribution of large canopy gaps may reflect underlying variation in mortality and growth processes. However, a lack of data at the appropriate scale has limited our ability to study this relationship until now. We detected canopy gaps using a unique LiDAR dataset consisting of 650 transects randomly distributed across 2500 km2 of the Brazilian Amazon. We characterized the size distribution of canopy gaps using a power law and we explore the variation in the exponent, α. We evaluated how the α varies across the Amazon, in response to disturbance by humans and natural environmental processes that influence tree mortality rates. We observed that South‐eastern forests contained a higher proportion of large gaps than North‐western, which is consistent with recent work showing greater tree mortality rates in the Southeast than the Northwest. Regions characterized by strong wind gust speeds, frequent lightning and greater water shortage also had a high proportion of large gaps, indicating that geographical variation in α is a reflection of underlying disturbance processes. Forests on fertile soils were also found to contain a high proportion of large gaps, in part because trees grow tall on these sites and create large gaps when they fall; thus, canopy gap analysis picked up differences in growth as well as mortality processes. Finally, we found that human‐modified forests had a higher proportion of large gaps than intact forests, as we would expect given that these forests have been disturbed. Synthesis. The proportion of large gaps in the forest canopy varied substantially over the Brazilian Amazon. We have shown that the trends can be explained by geographical variation in disturbance and growth. The frequency of extreme weather events is predicted to increase under climate change, and changes could lead to greater forest disturbance, which should be detectable as an increased proportion of large gaps in intact forests.

A statistical analysis of the distribution of convective windstorms and their radar characteristics in Hubei Province, China. Part 2

A statistical analysis of the distribution of convective windstorms and their radar characteristics in Hubei Province, China. Part 2

An improvement of wind gust estimate (WGE) method for squall lines

Severe wind gusts produced by squall lines are difficult to monitor and forecast. This paper assessed and improved the physics-based Brasseur WGE (wind gust estimate) method for diagnosing wind gust of squall lines by coupling the WGE methods with the WRF (Weather Research and Forecasting) model. The simulation results show that the Brasseur WGE method accurately captured the strong gust feature with 32 m·s−1 maximum wind speed during the disastering Shipwreck event occurred over Yangtze River on 1 June 2015, but overestimated the extended area of severe gust speeds. Analysis of the kinematic structure and boundary-layer conditions of the squall line confirmed the theoretical applicability of the Brasseur WGE method for squall lines. A novel gust-front-area limiting method was introduced to modify the Brasseur WGE method, which effectively reduces its gust wind overestimation area. Furthermore, five squall line events occurred in the middle China during 2021 were simulated to test the modified WGE method and the results exhibit significant improvements to the wind gust forecasts, with an average false alarm rate decreased from 0.89 to 0.54, and the critical success index(CSI) increased from 0.1 to 0.4.

Geotope of boulder accumulations: Possible source of noise in the dendrogeomorphic dating of landslides

Dendrogeomorphic dating is an effective tool for the assessment of past landslide activity. However, some complex landslide areas include zones of accumulated boulders that can represent geotopes with deteriorated conditions for the stable anchoring of tree roots. Under such conditions, wind gusts can easily cause stem tilting and subsequently be a source of growth disturbances and false landslide events. This study evaluated this possible source of uncertainty in tree rings based on the dating of selected flow-like shaped accumulations of boulders in the Outer Western Carpathians.The data from 94 Norway spruce (Picea abies (L.) Karst.) individuals provided evidence of 154 growth disturbances that were fully comparable with the frequency of active landslides. However, geophysical geoelectrical sounding in combination with field mapping suggests that the studied accumulation is stable. Growth disturbances enabled the reconstruction of nine past events, reaching the minimal threshold of the percentage index. Analysis of triggers detected the occurrence of above-average wind gust speeds in event years compared to other years. Moreover, the dated growth disturbances were not present in the reference trees, probably due to the more stable positions of these trees and thus their better resistance to wind forces. Moreover, the duration of growth disturbances in event years was significantly longer than that of disturbances in other years. The abovementioned evidence suggests that wind gusts are the most effective agents to induce growth disturbances in trees located at boulder accumulations. Subsequently, wind gusts have a strong impact on the resulting chronology of landslide events in the sense of inducing an important proportion of false events. Thus, the findings of this study clearly suggest avoiding boulder accumulations during the dendrogeomorphic dating of past landslide activity.

The Legacy of Hurricanes, Historic Land Cover, and Municipal Ordinances on Urban Tree Canopy in Florida (United States)

Urban Tree Canopy (UTC) greatly enhances the livability of cities by reducing urban heat buildup, mitigating stormwater runoff, and filtering airborne particulates, among other ecological services. These benefits, combined with the relative ease of measuring tree cover from aerial imagery, have led many cities to adopt management strategies based on UTC goals. In this study, we conducted canopy analyses for 300 cities in Florida to assess the impacts of development practices, urban forest ordinances, and hurricanes on tree cover. Within the cities sampled, UTC ranged from 5.9 to 68.7% with a median canopy coverage of 32.3% Our results indicate that the peak gust speeds recorded during past hurricanes events were a significant predictor of canopy coverage (P = 0.001) across the sampled cities. As peak gust speeds increased from 152 km/h (i.e., a lower-intensity Category 1 storm) to 225 km/h (lower-intensity Category 4 and the maximum gusts captured in our data), predicted canopy in developed urban areas decreased by 7.7%. Beyond the impacts of hurricanes and tropical storms, we found that historic landcover and two out of eight urban forest ordinances were significant predictors of existing canopy coverage (P-landcover < 0.001; P-tree preservation ordinance = 0.02, P-heritage tree ordinance = 0.03). Results indicate that some local policies and tree protections can potentially impact urban tree canopy, even in the face of rapid development and periodic natural disturbances.

Are anemometers at airports affected by taxiing aircraft?

This study provides evidence to discount any need to correct wind speeds measured at airports for jet exhaust from aircraft taxiing past the anemometer. The figure shows the manufacturer's data for an Airbus 320 engine at ‘ground idle’ extrapolated into the far field as a Gaussian wall jet model, showing that the jet exhaust is expected to pass underneath anemometers at 10m above ground. This is confirmed by matching 503 large-jet departures from runway 1L at Tampa International, FL, to the 1min interval gust speed and direction data recorded by the anemometer.

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

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.

Rapid advancement of spring migration and en route adjustment of migration timing in response to weather during fall migration in Vaux’s Swifts (Chaetura vauxi)

Climate change has generated earlier springs, later falls, and different weather patterns. These changes may prove challenging to migratory species if they are unable to adjust their migratory timing. We analyzed changes in migratory timing of Vaux’s Swifts (Chaetura vauxi (J.K. Townsend, 1839)) by examining first arrivals (date the first swift arrived) and peak roost occupancy (date the maximum number of swifts were observed) at migratory roosts in both spring and fall from the citizen science organization Vaux’s Happening. First arrivals and peak occupancy date in Vaux’s Swifts advanced over time from 2008 to 2017, and the timing of first arrivals advanced with an increase in local wind gust speeds. In contrast, fall migration timing did not change over time from 2008 to 2016, but higher temperatures were associated with later fall migration (both first arrival and peak roost occupancy) and higher local wind speeds were associated with earlier fall migration (peak roost occupancy only). Like many other migratory birds, Vaux’s Swifts may be tracking earlier spring phenology, and may also be altering their migratory timing in response to local weather conditions, especially during fall migration. Our results indicate that swifts may be able to adjust their migration to a changing climate, at least in the short term.

Damages Scale as a Supporting Tool for Windstorm Early Warning System in Malaysia

It is a fact that windstorm is a natural disaster that can create enormous damages. Thus, the article aims to serve as a guideline in establishing the damages scale as the supporting tool in the windstorm disaster management. The purpose of the scale is to mitigate impacts of windstorm via early warning system, so that local authorities and public at the affected area are able to know the worst-case scenario if windstorm occurred and could make early preparation in minimising the impacts. The damage scale is established based on the current damage criteria as an early warning of windstorm occurrences was adopted from the damages scale which was established outside Malaysia. On the other hand, there is no damages scale originally established in the country. In order to establish this supporting tool, 51 windstorm occurrences in year 2012 to 2016 from 6 districts in Peninsular Malaysia were selected as a study case and 246 damages were assessed. Besides windstorm damages, gust speed, wind direction, rainfall and radar images as raw data, the study also acquires local conditions wind multiplier map coordinated with meteorological station and overlaid with wind direction map at the study area as well. All the damage locations for each windstorm occurrence will be coordinated in the local conditions wind multiplier map. However, the damages which located underneath the same convective cluster with meteorological station, in position with wind direction and gust speed greater than hazard threshold only will be determined its associated intensity. The scale listed each potential damage according to categories either building, property, or tree. The gust speeds at 1-minute in the scale are between 9.0 m/s to 19.3 m/s. From the study, damages scale has similar hierarchy of level damages with existing damages scale but much lower intensity.

Does the winter storm-related wind gust intensity in Germany increase under warming climate? – A high-resolution assessment

Destructive winter storms cause recurring major damage to physical, biological, human, and managed systems in Central Europe. Therefore, detailed knowledge of their future development in many areas of human life is of great importance for planning strategic management decisions. One feature to characterise the winter storm intensity is the daily maximum gust speed for a 10-yr return period (GS10yr). In this study, the development of GS10yr under the representative concentration pathways RCP45 and RCP85 in the near future (2019–2049), mid future (2044–2074), and far future (2069–2099) was assessed. Gust speed projections were derived from 19 regional climate models (RCM) available from the EURO-CORDEX initiative. The GS10yr estimates were first bias-corrected and then combined with the historical winter storm atlas for Germany (GeWiSA) yielding highly resolved (25 m × 25 m) GS10yr grids. The results which are available on a monthly basis, indicate a significant increase in winter storm-related wind gust intensity in October under RCP45 and in November and December under RCP85 towards the end of the 21st century. The proposed methodology allows the quantification of the uncertainty associated with winter storm projections and the development of climate-sensitive storm damage models.

Extreme wind return periods from tropical cyclones in Bangladesh: insights from a high-resolution convection-permitting numerical model

Abstract. We use high-resolution (4.4 km) numerical simulations of tropical cyclones to produce exceedance probability estimates for extreme wind (gust) speeds over Bangladesh. For the first time, we estimate equivalent return periods up to and including a 1-in-200 year event, in a spatially coherent manner over all of Bangladesh, by using generalised additive models. We show that some northern provinces, up to 200 km inland, may experience conditions equal to or exceeding a very severe cyclonic storm event (maximum wind speeds in ≥64 kn) with a likelihood equal to coastal regions less than 50 km inland. For the most severe super cyclonic storm events (≥120 kn), event exceedance probabilities of 1-in-100 to 1-in-200 events remain limited to the coastlines of southern provinces only. We demonstrate how the Bayesian interpretation of the generalised additive model can facilitate a transparent decision-making framework for tropical cyclone warnings.

Estimation Technique of Minimum Energy Required for Complete Deployment of Folded Fin Under Gust Requirement (II): Considering Time Constraint

A previously developed estimation technique, of the minimum energy required for complete fin deployment under an operational requirement of gust speed, was modified to consider time consumed for fin unfolding as an additional requirement, which might lead to an increase of the required energy. Some modifications were made such as non-zero kinetic energy of unfolding fin when completely deployed and its monotonically increasing angular speed during unfolding motion having a profile of square-root function which helped to properly evaluate elapsed time for fin unfolding and to combine the additional time constraint with the fin folding motion equation including external moments of aerodynamics, gravitation, and friction, while, in the previous study, zero energy and bell-shaped speed profile had been used. Demonstrations of this estimation technique considering the time constraint additionally to the gust speed requirement were carried out with the same unfolding fin system and torque profiles used in the previous study and showed that unfolding systems equipped with energy estimated by this technique met all the given gust requirement and time constraint, irrespective of their torque profile, in terms of elapsed time for fin unfolding and allowable wind speed denoting the maximum speed of gust against which in every direction fin could deploy.

WegenerNet high-resolution weather and climate data from 2007 to 2020

Abstract. This paper describes the latest reprocessed data record (version 7.1) over 2007 to 2020 from the WegenerNet climate station networks, which since 2007 have been providing measurements with very high spatial and temporal resolution of hydrometeorological variables for two regions in the state of Styria, southeastern Austria: (1) the WegenerNet Feldbach Region, in the Alpine forelands of southeastern Styria, which extends over an area of about 22 km × 16 km and comprises 155 meteorological stations placed on a tightly spaced grid with an average spatial density of 1 station per ∼ 2 km2 and a temporal sampling of 5 min, and (2) the WegenerNet Johnsbachtal, which is a smaller “sister network” of the WegenerNet Feldbach Region in the mountainous Alpine region of upper Styria that extends over an area of about 16 km × 17 km and comprises 13 meteorological stations and 1 hydrographic station at altitudes ranging from below 600 m to over 2100 m and with a temporal sampling of 10 min. These networks operate on a long-term basis and continuously provide quality-controlled station time series for a multitude of hydrometeorological near-surface and surface variables, including air temperature, relative humidity, precipitation, wind speed and direction, wind gust speed and direction, soil moisture, soil temperature, and others like pressure and radiation variables at a few reference stations. In addition, gridded data are available at a resolution of 200 m × 200 m for air temperature, relative humidity, precipitation, and heat index for the Feldbach region and at a resolution of 100 m × 100 m for the wind parameters for both regions. Here we describe this dataset (the most recent reprocessing version 7.1) in terms of the measurement site and station characteristics as well as the data processing, from raw data (level 0) via quality-controlled basic station data (level 1) to weather and climate data products (level 2). In order to showcase the practical utility of the data, we also include two illustrative example applications, briefly summarize and refer to scientific uses in a range of previous studies, and briefly inform about the most recent WegenerNet advancements in 2020 towards a 3D open-air laboratory for climate change research. The dataset is published as part of the University of Graz Wegener Center's WegenerNet data repository under the DOI https://doi.org/10.25364/WEGC/WPS7.1:2021.1 (Fuchsberger et al., 2021) and is continuously extended.