Testing Water Yield, Efficiency of Different Meshes and Water Quality with a Novel Fog Collector for High Wind Speeds

Savonius rotors are large and heavy because they use drag force for propulsion. This leads to a larger investment in comparison to horizontal axis wind turbine (HAWT) rotors using lift forces. A simple construction of the Savonius rotor is preferred to reduce the production effort. Therefore, it is proposed here to use single-segment rotors of high elongation. Nevertheless, this rotor type must be compared with a multi-segment rotor to prove that the simplification does not deteriorate the effectiveness. The number of segments affects the aerodynamic performance of the rotor, however, the results shown in the literature are inconsistent. The paper presents a new observation that the relation between the effectiveness of single- and multi-segment rotors depends on the wind velocity. A single-segment rotor becomes significantly more effective than a four-segment rotor at low wind speeds. At high wind speeds, the effectiveness of both rotors becomes similar.

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Spray deposits from aerial insecticide spray simulant applications to a coniferous plantation in low and high wind speeds

Crop Protection ◽

10.1016/0261-2194(94)90162-7 ◽

1994 ◽

Vol 13 (2) ◽

pp. 121-126 ◽

Cited By ~ 3

Author(s):

Nicholas J. Payne

Keyword(s):

High Wind ◽

Wind Speeds ◽

Coniferous Plantation ◽

Insecticide Spray

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Midlatitude cyclones in convection permitting climate simulations: the added value offered for extreme wind speeds and sting-jets

10.5194/egusphere-egu21-12795 ◽

2021 ◽

Author(s):

Colin Manning ◽

Elizabeth Kendon ◽

Hayley Fowler ◽

Nigel Roberts ◽

Segolene Berthou ◽

...

Keyword(s):

Climate Model ◽

Surface Wind ◽

Added Value ◽

Large Contribution ◽

High Wind ◽

Wind Speeds ◽

Wind Gusts ◽

Climate Simulations ◽

Extreme Wind ◽

Extreme Wind Speeds

<p>Extra-tropical windstorms are one of the costliest natural hazards affecting Europe, and windstorms that develop a phenomenon known as a sting-jet account for some of the most damaging storms. A sting-jet (SJ) is a mesoscale core of high wind speeds that occurs in particular types of cyclones, specifically Shapiro-Keyser (SK) cyclones, and can produce extremely damaging surface wind gusts. High-resolution climate models are required to adequately model SJs and so it is difficult to gauge their contribution to current and future wind risk. In this study, we develop a low-cost methodology to automate the detection of sting jets, using the characteristic warm seclusion of SK cyclones and the slantwise descent of high wind speeds, within pan-European 2.2km convection-permitting climate model (CPM) simulations. Following this, we quantify the contribution of such storms to wind risk in Northern Europe in current and future climate simulations, and secondly assess the added value offered by the CPM compared to a traditional coarse-resolution climate model. This presentation will give an overview of the developed methods and the results of our analysis.</p><p>Comparing with observations, we find that the representation of wind gusts is improved in the CPM compared to ERA-Interim reanalysis data. Storm severity metrics indicate that SK cyclones account for the majority of the most damaging windstorms. The future simulation produces a large increase (>100%) in the number of storms exceeding high thresholds of the storm metric, with a large contribution to this change (40%) coming from windstorms in which a sting-jet is detected. Finally, we see a systematic underestimation in the GCM compared to the CPM in the frequency of extreme wind speeds at 850hPa in the cold sector of cyclones, likely related to better representation of sting-jets and the cold conveyor belt in the CPM. This underestimation is between 20-40% and increases with increasing wind speed above 35m/s. We conclude that the CPM adds value in the representation of severe surface wind gusts, providing more reliable future projections and improved input for impact models.</p>

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Relationship between Sea Surface Drag Coefficient and Wave State

Journal of Marine Science and Engineering ◽

10.3390/jmse9111248 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1248

Author(s):

Jian Shi ◽

Zhihao Feng ◽

Yuan Sun ◽

Xueyan Zhang ◽

Wenjing Zhang ◽

...

Keyword(s):

Drag Coefficient ◽

Momentum Flux ◽

Sea Surface ◽

Sea Spray ◽

Wave Age ◽

High Wind ◽

Surface Drag ◽

Wave State ◽

Wind Speeds ◽

Strong Winds

The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (CD) does not increase linearly with the increasing wind speed, namely, the increase of CD is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective CD (CD, eff) under strong winds. Our results indicate that wave age plays an important role in determining CD. When the wave age is >0.4, CD decreases with the wave age. However, when the wave age is ≤0.4, CD increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds.

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A Review of Parameterizations for Enthalpy and Momentum Fluxes from Sea Spray in Tropical Cyclones

Journal of Physical Oceanography ◽

10.1175/jpo-d-21-0023.1 ◽

2021 ◽

Author(s):

Sydney Sroka ◽

Kerry Emanuel

Keyword(s):

Tropical Cyclones ◽

Critical Role ◽

Sea Spray ◽

High Wind ◽

High Wind Speed ◽

Wind Speeds ◽

Crucial Component ◽

Momentum Fluxes ◽

Interaction Scheme ◽

Speed Regime

AbstractThe intensity of tropical cyclones is sensitive to the air-sea fluxes of enthalpy and momentum. Sea spray plays a critical role in mediating enthalpy and momentum fluxes over the ocean’s surface at high wind speeds, and parameterizing the influence of sea spray is a crucial component of any air-sea interaction scheme used for the high wind regime where sea spray is ubiquitous. Many studies have proposed parameterizations of air-sea flux that incorporate the microphysics of sea spray evaporation and the mechanics of sea spray stress. Unfortunately, there is not yet a consensus on which parameterization best represents air-sea exchange in tropical cyclones, and the different proposed parameterizations can yield substantially different tropical cyclone intensities. This paper seeks to review the developments in parameterizations of the sea spray-mediated enthalpy and momentum fluxes for the high wind speed regime and to synthesize key findings that are common across many investigations.

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Mass transfer velocity across the breaking air–water interface at extremely high wind speeds

Tellus B ◽

10.3402/tellusb.v65i0.21341 ◽

2013 ◽

Vol 65 (1) ◽

pp. 21341 ◽

Cited By ~ 27

Author(s):

Koji Iwano ◽

Naohisa Takagaki ◽

Ryoichi Kurose ◽

Satoru Komori

Keyword(s):

Mass Transfer ◽

Water Interface ◽

High Wind ◽

Transfer Velocity ◽

Wind Speeds ◽

Air Water Interface

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Hydrological Alteration Index as an Indicator of the Calibration Complexity of Water Quantity and Quality Modeling in the Context of Global Change

Water ◽

10.3390/w12010115 ◽

2019 ◽

Vol 12 (1) ◽

pp. 115 ◽

Cited By ~ 3

Author(s):

Roxelane Cakir ◽

Mélanie Raimonet ◽

Sabine Sauvage ◽

Javier Paredes-Arquiola ◽

Youen Grusson ◽

...

Keyword(s):

Climate Change ◽

Water Quality ◽

Water Resources ◽

Stream Water ◽

Swat Model ◽

Water Yield ◽

Observation Data ◽

Hydrological Alteration ◽

Water Quality And Quantity ◽

The Impact

Modeling is a useful way to understand human and climate change impacts on the water resources of agricultural watersheds. Calibration and validation methodologies are crucial in forecasting assessments. This study explores the best calibration methodology depending on the level of hydrological alteration due to human-derived stressors. The Soil and Water Assessment Tool (SWAT) model is used to evaluate hydrology in South-West Europe in a context of intensive agriculture and water scarcity. The Index of Hydrological Alteration (IHA) is calculated using discharge observation data. A comparison of two SWAT calibration methodologies are done; a conventional calibration (CC) based on recorded in-stream water quality and quantity and an additional calibration (AC) adding crop managements practices. Even if the water quality and quantity trends are similar between CC and AC, water balance, irrigation and crop yields are different. In the context of rainfall decrease, water yield decreases in both CC and AC, while crop productions present opposite trends (+33% in CC and −31% in AC). Hydrological performance between CC and AC is correlated to IHA: When the level of IHA is under 80%, AC methodology is necessary. The combination of both calibrations appears essential to better constrain the model and to forecast the impact of climate change or anthropogenic influences on water resources.

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Catch Characteristics of Precipitation Gauges in High-Latitude Regions with High Winds

Journal of Hydrometeorology ◽

10.1175/jhm542.1 ◽

2006 ◽

Vol 7 (5) ◽

pp. 984-994 ◽

Cited By ~ 21

Author(s):

Konosuke Sugiura ◽

Tetsuo Ohata ◽

Daqing Yang

Keyword(s):

Wind Speed ◽

High Latitude ◽

Cold Climate ◽

Strong Wind ◽

Blowing Snow ◽

High Wind ◽

Wind Speeds ◽

Solid Precipitation ◽

High Winds ◽

Correction Equations

Abstract Intercomparison of solid precipitation measurement at Barrow, Alaska, has been carried out to examine the catch characteristics of various precipitation gauges in high-latitude regions with high winds and to evaluate the applicability of the WMO precipitation correction procedures. Five manual precipitation gauges (Canadian Nipher, Hellmann, Russian Tretyakov, U.S. 8-in., and Wyoming gauges) and a double fence intercomparison reference (DFIR) as an international reference standard have been installed. The data collected in the last three winters indicates that the amount of solid precipitation is characteristically low, and the zero-catch frequency of the nonshielded gauges is considerably high, 60%–80% of precipitation occurrences. The zero catch in high-latitude high-wind regions becomes a significant fraction of the total precipitation. At low wind speeds, the catch characteristics of the gauges are roughly similar to the DFIR, although it is noteworthy that the daily catch ratios decreased more rapidly with increasing wind speed compared to the WMO correction equations. The dependency of the daily catch ratios on air temperature was confirmed, and the rapid decrease in the daily catch ratios is due to small snow particles caused by the cold climate. The daily catch ratio of the Wyoming gauge clearly shows wind-induced losses. In addition, the daily catch ratios are considerably scattered under strong wind conditions due to the influence of blowing snow. This result suggests that it is not appropriate to extrapolate the WMO correction equations for the shielded gauges in high-latitude regions for high wind speed of over 6 m s−1.

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Calibration and Cross Validation of Global Ocean Wind Speed Based on Scatterometer Observations

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-19-0119.1 ◽

2020 ◽

Vol 37 (2) ◽

pp. 279-297 ◽

Cited By ~ 7

Author(s):

Agustinus Ribal ◽

Ian R. Young

Keyword(s):

Wind Speed ◽

Cross Validation ◽

Regression Line ◽

Total Duration ◽

Global Ocean ◽

High Wind ◽

Wind Speeds ◽

Buoy Data ◽

Ocean Wind

AbstractGlobal ocean wind speed observed from seven different scatterometers, namely, ERS-1, ERS-2, QuikSCAT, MetOp-A, OceanSat-2, MetOp-B, and Rapid Scatterometer (RapidScat) were calibrated against National Data Buoy Center (NDBC) data to form a consistent long-term database of wind speed and direction. Each scatterometer was calibrated independently against NDBC buoy data and then cross validation between scatterometers was performed. The total duration of all scatterometer data is approximately 27 years, from 1992 until 2018. For calibration purposes, only buoys that are greater than 50 km offshore were used. Moreover, only scatterometer data within 50 km of the buoy and for which the overpass occurred within 30 min of the buoy recording data were considered as a “matchup.” To carry out the calibration, reduced major axis (RMA) regression has been applied where the regression minimizes the size of the triangle formed by the vertical and horizontal offsets of the data point from the regression line and the line itself. Differences between scatterometer and buoy data as a function of time were investigated for long-term stability. In addition, cross validation between scatterometers and independent altimeters was also performed for consistency. The performance of the scatterometers at high wind speeds was examined against buoy and platform measurements using quantile–quantile (Q–Q) plots. Where necessary, corrections were applied to ensure scatterometer data agreed with the in situ wind speed for high wind speeds. The resulting combined dataset is believed to be unique, representing the first long-duration multimission scatterometer dataset consistently calibrated, validated and quality controlled.

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