Peak Wind Research Articles

Assessment of hurricane generated loads on offshore wind farms; a closer look at most extreme historical hurricanes in New England

We simulated and assessed the environmental forces including wave and wind loads generated by the most extreme historical hurricanes in the US northeast within the proposed offshore/planned wind farms: Hurricane Carol in 1954, and 1938 New England hurricane. Offshore wind energy industry is on the verge of rapid growth off the US east coast. Development of wind energy projects in this area requires a comprehensive assessment of hurricane risks in planning and operation stages. In this study, we used an ocean modeling system (COAWST: Coupled Ocean Atmosphere Wave Sediment Transport) to better understand and characterize hurricane-generated loads within the planned wind farm sites offshore Rhode Island and Massachusetts. The COAWST model was first validated using observed data and then applied to hurricanes with return periods of around 500-year (recommended by IEC 61400-3-1). Hurricane Carol and 1938 hurricane were simulated using a parametric model which generated the peak wind speeds of 49 m/s and 45 m/s, spatially averaged over the area, that led to significant wave heights of 11.90 m and 9.80 m, respectively. .Spatial variability of the wind and wave loads within the proposed sites were assessed. Further, the effects of these variabilities on the structural response of a typical monopile were demonstrated using the OpenFAST Model. Results showed up to 60% spatial variability of hurricane loads in the leased areas. Results demonstrated the need of using advanced ocean modeling systems for planning and operation of wind farms as opposed to traditional statistical methods such as measure and correlate for site characterization.

Experimental Study on the Effects of Aspect Ratio on the Wind Pressure Coefficient of Piloti Buildings

Owing to strong winds during the typhoon season, damage to pilotis in the form of dropout of the exterior materials occurs frequently. Pilotis placed at the end exhibit a large peak wind pressure coefficient of the ceiling. In this study, the experimental wind direction angle of wind pressure tests was conducted in seven directions, with wind test angles varying from 0° to 90° at intervals of 15°, centered on the piloti position, which was accomplished using the wind tunnel experimental system. Regardless of the height of the building, the maximum peak wind pressure coefficient was observed at the center of the piloti, whereas the minimum peak wind pressure coefficient was noted at the corners, which corresponds with the wind direction inside the piloti. The distribution of the peak wind pressure coefficient was similar for both suburban and urban environments. However, in urban areas, the maximum peak wind pressure coefficient was approximately 1.4–1.7 times greater than that in suburban areas. The maximum peak wind pressure coefficient of the piloti ceiling was observed at the inside corner, whereas the minimum peak wind pressure coefficient was noted at the outer edge of the ceiling. As the height of the building increased, the maximum peak wind pressure coefficient decreased. Suburban and urban areas exhibited similar peak wind pressure distributions; however, the maximum peak wind pressure coefficient in urban areas was approximately 1.2–1.5 times larger than that in suburban areas.

Analysis of the Duration of High Winds During Landfalling Hurricanes

The duration of wind storms over a threshold wind speed value is known to be an important parameter in determining damage and losses, with losses tending to increase with the duration. This is because peak pressures tend to increase with longer duration, many building components and cladding systems are vulnerable to different types of fatigue mechanisms, and the yielding of linear elastic materials in the plastic range depends on the number of load cycles. A hurricane model was used to examine the duration of high winds in the United States at Miami, Galveston, and Charleston with the goal of establishing duration statistics for hurricanes as a function of peak wind speed. It was found that the duration of high winds, defined as the time that the 10 min wind speeds are within 30% of the peak 10 min wind speed, had a significant variation with a range from tens of minutes to more than 20 h, depending on location. The median duration ranged from 1.5 to 4 h at the three locations, depending on location and the design wind speed level (i.e., the risk Category of the building). These results were used to establish a simple normalized model for wind speed as a function of time, which could be used together with the design wind speed to establish load cycles for design.

Climatology of Near‐Surface Daily Peak Wind Gusts Across Scandinavia: Observations and Model Simulations

AbstractAn observed daily peak wind gusts (DPWG) dataset over Scandinavia, consisting of time series from 127 meteorological stations across Finland, Norway and Sweden, has been created. This dataset provides high‐quality and homogenized near‐surface DPWG series for Scandinavia, spanning the longest available time period (1996–2016). The aim of this study is to evaluate the ability of two regional climate models (RCMs) in simulating DPWG winds. According to the observed DPWG climatology, meteorological stations are classified into three regions for which wind conditions are influenced by similar physical processes: coast, inland and mountain. Smaller‐scale DPWG features of the three regions are only captured when coarser general circulation models or reanalyses are downscaled by a RCM. Dynamic downscaling is thus needed to achieve more realistic simulations of DPWG when compared to their driving models. The performances of the RCMs are found to be more dependent on model dynamics and physics (such as gust parametrization) than on the boundary conditions provided by the driving models. We also found that the RCMs cannot accurately simulate observed DPWG in inland and mountainous areas, suggesting the need for higher horizontal resolution and/or better representation of relevant boundary‐layer processes.

A Decline of Observed Daily Peak Wind Gusts with Distinct Seasonality in Australia, 1941–2016

AbstractWind gusts represent one of the main natural hazards due to their increasing socioeconomic and environmental impacts on, for example, human safety, maritime–terrestrial–aviation activities, engineering and insurance applications, and energy production. However, the existing scientific studies focused on observed wind gusts are relatively few compared to those on mean wind speed. In Australia, previous studies found a slowdown of near-surface mean wind speed, termed “stilling,” but a lack of knowledge on the multidecadal variability and trends in the magnitude (wind speed maxima) and frequency (exceeding the 90th percentile) of wind gusts exists. A new homogenized daily peak wind gusts (DPWG) dataset containing 548 time series across Australia for 1941–2016 is analyzed to determine long-term trends in wind gusts. Here we show that both the magnitude and frequency of DPWG declined across much of the continent, with a distinct seasonality: negative trends in summer–spring–autumn and weak negative or nontrending (even positive) trends in winter. We demonstrate that ocean–atmosphere oscillations such as the Indian Ocean dipole and the southern annular mode partly modulate decadal-scale variations of DPWG. The long-term declining trend of DPWG is consistent with the “stilling” phenomenon, suggesting that global warming may have reduced Australian wind gusts.

Signatures of Oceanic Wind Events in Geostationary Cloud Top Temperature and Lightning Data

AbstractA total of 13 ocean-based wind events from 2018, detected by buoys and Coastal-Marine Automated Network (C-MAN) stations, were analyzed using 1-min mesoscale sector Advanced Baseline Imager (ABI) cloud top brightness temperature (CTTB) data, as well as 1-min Geostationary Lightning Mapper (GLM) lightning data. The ABI and GLM instruments are located on the Geostationary Operational Environmental Satellite-16 (GOES-16) satellite. An oceanic wind event was defined as a buoy or C-MAN station-recorded peak wind gust of at least 14 m s−1, associated with a convective storm. The wind gust was required to exceed the wind speed by at least 4 m s−1 at the time of the event, but not exceed the corresponding wind speed by at least 4 m s−1 for more than 30 min. This study hypothesized that prior to a wind event, there should be unique signatures in ABI CTTB and GLM lightning datasets. The presumption was that the minimum CTTB and maximum flash rate should occur near the same time and prior to the event. The minimum CTTB occurred an average of 10.5 min and a median of 7 min prior to events, with a range from 29 min prior to 1 min after the event. Changes in CTTB were often subtle. A maximum flash rate occurred within 5 min of the minimum CTTB for 11 of the 12 events with lightning and did not exceed 11 flashes per minute for 9 of the 12 events with lightning. Operational weather forecasters might use CTTB and lightning trends to help identify storms capable of producing significant oceanic wind events.

Supercell tornadoes are much stronger and wider than damage-based ratings indicate

Tornadoes cause damage, injury, and death when intense winds impact structures. Quantifying the strength and extent of such winds is critical to characterizing tornado hazards. Ratings of intensity and size are based nearly entirely on postevent damage surveys [R. Edwards et al., Bull. Am. Meteorol. Soc. 94, 641-653 (2013)]. It has long been suspected that these suffer low bias [C. A. Doswell, D. W. Burgess, Mon. Weather Rev. 116, 495-501 (1988)]. Here, using mapping of low-level tornado winds in 120 tornadoes, we prove that supercell tornadoes are typically much stronger and wider than damage surveys indicate. Our results permit an accurate assessment of the distribution of tornado intensities and sizes and tornado wind hazards, based on actual wind-speed observations, and meaningful comparisons of the distribution of tornado intensities and sizes with theoretical predictions. We analyze data from Doppler On Wheels (DOW) radar measurements of 120 tornadoes at the time of peak measured intensity. In striking contrast to conventional damage-based climatologies, median tornado peak wind speeds are ∼60 m⋅s-1, capable of causing significant, Enhanced Fujita Scale (EF)-2 to -3, damage, and 20% are capable of the most intense EF-4/EF-5 damage. National Weather Service (NWS) EF/wind speed ratings are 1.2 to 1.5 categories (∼20 m⋅s-1) lower than DOW observations for tornadoes documented by both the NWS and DOWs. Median tornado diameter is 250 to 500 m, with 10 to 15% >1 km. Wind engineering tornado-hazard-model predictions and building wind resistance standards may require upward adjustment due to the increased wind-damage risk documented here.

Numerical Analysis of Storm Surges on Canada’s Western Arctic Coastline

A numerical study was conducted to characterize the probability and intensity of storm surge hazards in Canada’s western Arctic. The utility of the European Centre for Medium-Range Weather Forecasts Reanalysis 5th Generation (ERA5) dataset to force numerical simulations of storm surges was explored. Fifty historical storm surge events that were captured on a tide gauge near Tuktoyaktuk, Northwest Territories, were simulated using a two-dimensional (depth-averaged) hydrodynamic model accounting for the influence of sea ice on air-sea momentum transfer. The extent of sea ice and the duration of the ice season has been reducing in the Arctic region, which may contribute to increasing risk from storm surge-driven hazards. Comparisons between winter storm events under present-day ice concentrations and future open-water scenarios revealed that the decline in ice cover has potential to result in storm surges that are up to three times higher. The numerical model was also used to hindcast a significant surge event that was not recorded by the tide gauge, but for which driftwood lines along the coast provided insights to the high-water marks. Compared to measurements at proximate meteorological stations, the ERA5 reanalysis dataset provided reasonable estimates of atmospheric pressure but did not accurately capture peak wind speeds during storm surge events. By adjusting the wind drag coefficients to compensate, reasonably accurate predictions of storm surges were attained for most of the simulated events. The extreme value probability distributions (i.e., return periods and values) of the storm surges were significantly altered when events absent from the tide gauge record were included in the frequency analysis, demonstrating the value of non-conventional data sources, such as driftwood line surveys, in supporting coastal hazard assessments in remote regions.

Evaluation of the Surface Wind Field over Land in WRF Simulations of Hurricane Wilma (2005). Part II: Surface Winds, Inflow Angles, and Boundary Layer Profiles

AbstractThis is the second of a two-part study that explores the capabilities of a mesoscale atmospheric model to reproduce the near-surface wind fields in hurricanes over land. The Weather Research and Forecasting (WRF) Model is used with two planetary boundary layer parameterizations: the Yonsei University (YSU) and the Mellor–Yamada–Janjić (MYJ) schemes. The first part presented the modeling framework and initial conditions used to produce simulations of Hurricane Wilma (2005) that closely reproduced the track, intensity, and size of its wind field as it passed over South Florida. This part explores how well these simulations can reproduce the winds at fixed points over land by making comparisons with observations from airports and research weather stations. The results show that peak wind speeds are remarkably well reproduced at several locations. Wind directions are evaluated in terms of the inflow angle relative to the storm center, and the simulated inflow angles are generally smaller than observed. Localized peak wind events are associated with vertical vorticity maxima in the boundary layer with horizontal scales of 5–10 km. The boundary layer winds are compared with wind profiles obtained by velocity–azimuth display (VAD) analyses from National Weather Service Doppler radars at Miami and Key West, Florida; results from these comparisons are mixed. Nonetheless the comparisons with surface observations suggest that when short-term hurricane forecasts can sufficiently predict storm track, intensity, and size, they will also be able to provide useful information on extreme winds at locations of interest.

Short-term prediction of downburst winds: A double-step modification enhanced approach

The downburst wind is an extreme wind event with rapidly increasing and afterwards descending wind velocities in a short period. The prediction of downburst winds, especially for the peak wind velocity and its occurrence time, is a critical issue in engineering communities. In this paper, typical commonly used time-series models are firstly employed to predict the downburst winds based on measured data, and the measured results are found highly underestimated with a prominent time lag. According to the faced problem, a double-step modification enhanced approach is developed to improve the prediction accuracy of time-series models. Central to this approach is the dual modifications, in which the first modification remedies the underestimation by correcting the error linearly correlated to the measured wind velocity, while the second modification compensates the residual error negatively proportional to the wind velocity after the first modification. The developed approach is then compared with other time-varying and nonlinear forecasting models, and the dual modifications are found to be able to highly improve the prediction accuracies of these models. Finally, the efficacy of the developed approach is further verified via case studies concerning the one-step and multi-step ahead predictions. The satisfied predicted results prove the effectiveness of the developed approach in the short-term prediction of downburst winds. Thus, the double-step modification enhanced approach can be used for early-warning purposes.

Role of Advection on the Evolution of Near-Surface Temperature and Wind in Urban-Aware Simulations

AbstractThe role of advection of heat and momentum on the evolution of near-surface temperature and wind is evaluated in urban-aware simulations over Houston, Texas, under dry conditions on a light-wind day. Two sets of experiments, each consisting of four simulations using different planetary boundary layer (PBL) schemes, were conducted over 48 h using the default urban scheme (BULK) and the single-layer urban canopy model (SLUCM) available within the Weather Research and Forecasting Model. We focus on understanding and quantifying the role played by temperature and momentum advection, particularly on the windward and leeward sides of the city. Previous studies have largely ignored any quantitative analysis of impacts from the advection of momentum over an urban area. The horizontal advection of temperature was found to be more important in the BULK because of the larger surface temperature gradient caused by warmer surface temperatures over urban areas than in the SLUCM. An analysis of the momentum budget shows that horizontal advection of zonal and meridional momentum plays a prominent role during the period of peak near-surface winds and that this effect is more pronounced in the windward side of the city. The local tendency in peak winds in the leeward side lags that in the windward side by about 1–2 h, similar to the lag found in horizontal momentum advection. The sensitivity of the results to different urban and PBL schemes was explored. The results imply that representation and influence of land-use patterns via sophisticated urban parameterizations generate locally driven winds that best resemble observations.

Effects of Architectural Irregularities on the Seismic Behavior of Buildings

Cooperation between the architect and the civil engineer has nowadays become essential in any project for the client’s requests’ sake. This study was made to show this idea’s importance and beneficial consequences. For this purpose, a 40-story dual-system high-rise building has been designed to resist moderate seismic and high wind loads. Three main models were formed: Starting with the net model, which is the regular model, followed by the mass irregularity models that were generated for the luxury floor desires (this irregularity was placed in two different locations, namely at the top and middle position), ending with the soft story irregularity models that were cited in the building’s middle and bottom for the gym floor’s need. The positions for each irregularity were tested and compared to those of the regular model under the effect of seismic load on one hand and under the influence of three different wind loads on the other. The required wind loads studied in this article were assigned from the wind speeds of 80, 100 and 120 mph. For these models’ analysis, RSA using finite element method on ETABS was used.The results exhibited that the peak wind speed this building held was 110 mph for both irregularities. Furthermore, the seismically-designed high-rise buildings might not be safe enough to resist a wind load speed of 120 mph. In addition, the middle location is the most preferable locus for these irregularities to occur regarding wind and seismic loads because of its minor displacement, drift and base shear. Besides, it ensured the economic cost of the mass irregularity ($1,706,380), which is in turn less than that of the top position ($1,790,187). The same applies for the stiffness irregularity cost, requiring a budget of $1,632,310 in the middle position but an expense of $1,676,368 for the bottom locus. Although the irregularity’s perfect location seemed unfamiliar, it pursues the sake of the client, the architect and the civil engineer alike.

Experimental–numerical investigation of momentary discomfort in a high-speed train in varying wind speed conditions

Understanding the effect of wind speed variation on wind-induced momentary discomfort is the basis to improve the train vibration comfort. This study focuses on this challenge. Firstly, the momentary discomfort evaluation index Pw is developed and proved by the full-scale test. Then, setting Pw as the critical value, a multi-body nonlinear numerical investigation of the effect of the wind speed change rate, peak-wind speed duration, and wind speed variation amplitude on momentary discomfort in a train is conducted. Furthermore, the unfavourable wind speed variation condition for the wind-induced momentary discomfort in the train is obtained. Results indicate that the most intense condition for the train vibration momentary discomfort appears when the change rate of wind speed is faster and the duration of the peak wind drives the car-body rolling to the limit position. Consequently, critical wind speed for the wind-induced momentary discomfort in changing wind speed conditions is proposed, which provides a reference for an efficient train operation scheme to improve vibration comfort in a train under wind speed variation conditions.

History of the peak three-second gust

The usage of the term “3-s gust” is commonplace throughout the wind engineering community. The term generally refers to the peak wind speed measured in some epoch (e.g., 1 ​h) with a specified gust duration – in this case 3 ​s (i.e., peak 3-s gust). There seems to be misconceptions on the origins of the peak 3-s gust amongst members of the engineering community. This historical review provides a general timeline of its usage in the literature and practice, reasons and rationale for the choice and provides thoughts for its use going forward.

The effect of continuously varying wind speed on high-speed train overturning safety

Changing topography will affect wind speed variations along railway lines in local areas. When the distance from one wind speed abrupt change location to other is narrow, a continuous variation in wind speed will occur. However, few studies have focused on this topic. In this study, a continuous wind speed variation model is developed based on measured wind speed curves, the interval time of continuous wind speed changes, the wind speed amplitude variation, the wind speed change rate and peak wind speed duration on the train dynamics are investigated. The results show that continuous wind speed variations have a significant impact on the overturning safety of trains compared to a single wind speed change. When the interval time between two adjacent wind speed changes is less than 6 s, it is necessary to consider the influence of continuous wind speed variations. In addition, the influence of the wind speed amplitude changes on train overturning safety is much greater than other factors.

An automated classification method of thunderstorm and non-thunderstorm wind data based on a convolutional neural network

Historical wind data analysis is a key part of estimating design wind loads. Current design standards do not separately consider the wind loading effects by different wind hazard types. One reason for this lack of consideration is that the separation between thunderstorm and non-thunderstorm wind data is still an issue. A previous study about the Automated Surface Observing System (ASOS) provided a classification method of wind data as thunderstorm or non-thunderstorm based on thunderstorm ‘flags’ (Lombardo et al., 2009). However, this method relies mainly on manual or automated weather observations which are limited to a subset of stations worldwide. This paper first develops a revised wind hazard type recognition method based on a neural network. In this method, the historical wind data recorded is segmented in different time domains to be applied in a one-dimensional convolutional neural network (1D-CNN) for an automated thunderstorm (T) or non-thunderstorm (NT) classification. Also, based on the trained 1D-CNN, a more comprehensive wind database can be extracted. The classification result from ASOS can automatically provide different peak wind speed for different wind hazard types.

Windblast testing of an aircrew helmet: An approach to neck load analysis

Introduction: Modern generation fighter aircraft has expanded the escape envelope for a fighter aircrew. With the ejection occurring at very high airspeeds, windblast is a cause of major injuries and fatalities. Flying helmet, before its induction into operational usage, must be tested in simulated windblast conditions to ensure that they provide adequate safety. Material and Methods: Windblast tests were conducted on a newly designed/procured helmet in a standard windblast test facility as per Mil Std MIL-V-29591/1. A large instrumented Hybrid III male dummy was used for the tests. The test conditions were: Wind speed 600 ± 60 KEAS, rise time of 125 ± 20 ms, time at peak wind velocity of 300 ± 50 ms, and total exposure time of ≥3 s. Structural integrity, retention with the headform, and recorded neck loads were assessed for interpretation of test results. Results: Helmets could withstand the windblast conditions without any significant structural failures and were retained with the headform during the entire duration of test conditions. However, analysis of the neck loads resulted in a significant dilemma in aeromedical decision-making, there being no laid down criteria in the Mil Specification. The neck tension forces were more than the acceptable limits and found to have the potential for significant neck injuries as per the Injury Assessment Reference Values specified in AGARD-AR-330 specifically in the tests where blast was head on and outer visor in up configuration; however, these values were within the acceptable limits as per the other proposed criteria. Similarly, analysis of the neck tension extension combined effects revealed conflicting outcomes for Nij performance limits specified in various standards. This paper discusses the critical analysis of neck loads vis-à-vis the neck injury criteria to understand the neck loads generated during windblast conditions and its implication on aircrew safety. Conclusion: Neck loads assessment is critical in predicting aircrew safety during windblast testing. In the absence of a clearly defined criteria in the Mil Specification, critical ananlysis of neck loads vis-à-vis recommended standards in scientific literature be done to make meaningful conclusion.

The whirlwinds of Elysium: A catalog and meteorological characteristics of “dust devil” vortices observed by InSight on Mars

A catalog of convective vortex encounters recorded by InSight on the Martian surface is presented, through Sol 390 of the mission. The catalog summarizes key meteorological parameters such as wind speed and direction before the event, peak wind, the duration and magnitude of the pressure excursion, temperatures and solar array data where present. Additional seismic parameters are also provided on seismometer-detected ground acceleration. The catalog is intended as a resource for vortex population studies, and as an index for examining these meteorological events in detail and to assess possible geophysical (seismic or magnetic) signatures. Whereas it is difficult to evaluate ‘anecdotal’ results in small surveys, the large number of events (853 with a pressure drop exceeding 0.8 Pa) in this work permits robust statistical evaluation. For example, it is found that three times as many pressure profiles have slower onsets than decays than vice versa, indicating an asymmetry in the surface pressure field due to the tilted advection of the vortex by ambient wind. A vortex area fraction of 0.07% during the most active six hours of the day is deduced.

On the use of synthetic tropical cyclones and hypothetical events for storm surge assessment under climate change

This study presents a new approach to assess storm surge risk from tropical cyclones under climate change by direct calculation of the local flood levels using a limited number of events with an associated probability. The approach is based on the near-worst-case flood scenario, associated with a known tropical cyclone wind intensity probability (return period). We applied the method for the locality of Manzanillo, Colima, Mexico, using synthetic tropical cyclones derived from six different general circulation models for the present and future climates under the Representative Concentration Pathway 8.5. The synthetic events allowed the characterization of the wind intensity for the present and future climates for a given return period, as well as to determine the key tropical cyclones parameters related to storm surge. For Hurricane Patricia (2015), the strongest tropical cyclone to impact the region, we determined that its 95 m/s winds have a return period above 4000 years for the present climate and 198 years in a future climate scenario. Using Hurricane Patricia’s peak wind intensity, we created hypothetical events representing all possible approaches of tropical cyclones (211 events) to Manzanillo. We forced a hydrodynamic model with the hypothetical events over a mesh created with LiDAR-derived topography and then calculated the storm surge to create the near-worst-case flood scenario based on the maximum envelopes of water (MEOWs) and the maximum of MEOWs. Using those results, we created flood risk maps at city block level based on the combination of flood hazard and socioeconomic vulnerability maps. The presented method provides a tool for tropical cyclones storm surge hazard and risk assessment by generating near-worst-case flood maps under projected climates using a limited set of hypothetical events.

Joint Use of Spaceborne Microwave Sensor Data and CYGNSS Data to Observe Tropical Cyclones

The joint use of spaceborne microwave sensor data and Cyclone Global Navigation Satellite System (CYGNSS) data to observe tropical cyclones (TCs) is presented in this paper. The Soil Moisture Active and Passive (SMAP) radiometer was taken as an example of a spaceborne microwave sensor, and its data and the CYGNSS data were fused to fix the center of a TC and to measure the maximum wind speed around the TC inner core. This process included data preprocessing, image fusion, determination of the TC center position, and the estimation of the TC’s intensity. For all of the observed hurricanes, the experimental results demonstrated that the proposed method obtains a more complete structure of the TC and can measure the surface wind speed around the TC inner core at more frequent intervals compared to the case where the SMAP radiometer data or the CYGNSS data are employed alone. Furthermore, when comparing the TC tracks obtained by the proposed method with the best tracks provided by the National Hurricane Center (NHC), we found that the mean absolute error values ranged between 18.4 and 46 km, the standard deviation varied between 15.1 and 28.2 km, and both of these were smaller than the values obtained by only using the CYGNSS data. In addition, when comparing the maximum wind speed around the TC inner core obtained by the proposed method with the best track peak winds estimated by the NHC, we found that the mean absolute error values ranged between 7.7 and 15.7 m/s, the root-mean-square difference values varied between 8.6 and 18 m/s, the correlation coefficients varied between 0.1782 and 0.9877, the bias values varied between −8.5 and 4.5 m/s, and all of these values were smaller in most cases, than those obtained by only using the CYGNSS data.