scholarly journals New Theory Connects Tree Uprooting and Sediment Movement

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Aaron Sidder
Keyword(s):  
Sediment Movement ◽  
Extreme Wind ◽  
Wind Events ◽  
Tree Uprooting

Tree throw from extreme wind events plays an important role in the movement of sediment and erosion on forested hillslopes. A new theory offers a novel way to measure its impact.

The Extreme Wind Events in the Ross Island Region of Antarctica

2016 ◽  
Vol 31 (3) ◽  
pp. 985-1000 ◽  
Author(s):  
Nicholas J. Weber ◽  
Matthew A. Lazzara ◽  
Linda M. Keller ◽  
John J. Cassano
Keyword(s):  
Structural Damage ◽  
Ross Sea ◽  
Enso Event ◽  
Central Pacific ◽  
Island Region ◽  
Back Trajectories ◽  
Extreme Wind ◽  
Mcmurdo Station ◽  
Wind Events ◽  
Upper Level

Abstract Numerous incidents of structural damage at the U.S. Antarctic Program’s (USAP) McMurdo Station due to extreme wind events (EWEs) have been reported over the past decade. Utilizing nearly 20 yr (~1992–2013) of University of Wisconsin automatic weather station (AWS) data from three different stations in the Ross Island region (Pegasus North, Pegasus South, and Willie Field), statistical analysis shows no significant trends in EWE frequency, intensity, or duration. EWEs more frequently occur during the transition seasons. To assess the dynamical environment of these EWEs, Antarctic Mesoscale Prediction System (AMPS) forecast back trajectories are computed and analyzed in conjunction with several other AMPS fields for the strongest events at McMurdo Station. The synoptic analysis reveals that McMurdo Station EWEs are nearly always associated with strong southerly flow due to an approaching Ross Sea cyclone and an upper-level trough around Cape Adare. A Ross Ice Shelf air stream (RAS) environment is created with enhanced barrier winds along the Transantarctic Mountains, downslope winds in the lee of the glaciers and local topography, and a tip jet effect around Ross Island. The position and intensity of these Ross Sea cyclones are most influenced by the occurrence of a central Pacific ENSO event, which causes the upper-level trough to move westward. An approaching surface cyclone would then be in position to trigger an event, depending on how the wind direction and speed impinges on the complex topography around McMurdo Station.

Extreme winds in a WRF downscaling for the SAM-22 CORDEX domain for the 1979-2018 Historical Period

2021 ◽  
Author(s):  
Natalia Pillar da Silva ◽  
Rosmeri Porfírio da Rocha ◽  
Natália Machado Crespo ◽  
Ricardo de Camargo ◽  
Jose Antonio Moreira Lima ◽  
...  
Keyword(s):  
Wind Speed ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Horizontal Resolution ◽  
Historical Period ◽  
Climate Projections ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Wind Events ◽  
Extreme Winds

<p>This study aims to evaluate how extreme winds (above the 95th percentile) are represented in a downscaling using the regional model WRF over the CORDEX South American domain in an approximate 25 km (0.22 degrees) horizontal resolution, along with CFSR as input. The main focus of the analysis resides over the coastal Brazilian region, given a large number of offshore structures from oil and gas industries subject to impact by severe events. Model results are compared with a reanalysis product (ERA5),  estimates from satellites product (Cross-Calibrated Multi-Platform Wind Speed), and available buoy data (Brazilian National Buoy Project). Downscaling results from WRF show an underestimation of maximum and extreme wind speeds over the region when compared to all references, along with overestimation in the continental areas. This directly impacts results for extreme value estimation for a larger return period and severity evaluation of extreme wind events in future climate projections. To address this, a correction procedure based on the linear relationship between severe wind from satellite and model results is applied. After linearly corrected, the extreme and maximum wind speed values increase and errors in the representation of severe events are reduced in the downscaling results.</p>

Classification and identification of synoptic and non-synoptic extreme wind events from surface observations in South America

2019 ◽  
Vol 193 ◽  
pp. 103963 ◽  
Author(s):  
Matthew B. Vallis ◽  
Acir Mércio Loredo-Souza ◽  
Vanessa Ferreira ◽  
Ernani de Lima Nascimento
Keyword(s):  
South America ◽  
Extreme Wind ◽  
Wind Events ◽  
Surface Observations

scholarly journals Extreme Wind Events Influence Seed Rain and Seedling Dynamics of Guam’s Serianthes nelsonii Merr

2019 ◽  
Vol 12 ◽  
pp. 194008291985376 ◽  
Author(s):  
Thomas E. Marler ◽  
Gil N. Cruz
Keyword(s):  
Tropical Cyclone ◽  
Habitat Restoration ◽  
Seedling Emergence ◽  
Seed Rain ◽  
Annual Number ◽  
Abrupt Increase ◽  
Species Recovery ◽  
Direct Observations ◽  
Extreme Wind ◽  
Wind Events

The seasonal aspects of Guam’s Serianthes nelsonii seed rain quantity, new seedling emergence, and lifespan of newly emerged seedlings were determined by direct observations. Two high wind events in January and September 2013 generated 63% of the annual number of new seeds collected in litterfall. A defoliating tropical cyclone in May 2015 generated an abrupt increase in seedling emergence with 17% of the annual new seedling count emerging during the 4-week period after the tropical cyclone. Of the annual count of seedlings that lived longer than 2 weeks, 8% of them emerged during the 7 months prior to the tropical cyclone in May 2015. In contrast, 92% of these long-lived seedlings emerged during the 5 months immediately after the tropical cyclone. Mitigating the limitations to regeneration and recruitment of Serianthes nelsonii will likely require a change in approach for species recovery such that holistic habitat restoration becomes the goal rather than species recovery per se.

Field Testing of a Wind Turbine Tubular Tower and Structural Design of a Space Frame Steel Tower

2013 ◽  
Vol 405-408 ◽  
pp. 1077-1084 ◽  
Author(s):  
Xiang Yang Wang ◽  
Kao Shan Dai ◽  
Yi Chao Huang
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Design ◽  
Field Testing ◽  
Structural Vibrations ◽  
Space Frame ◽  
Wind Turbine Tower ◽  
Extreme Wind ◽  
Wind Events ◽  
Supporting Structures

Wind energy industry has been growing tremendously in recent years. Tubular steel towers are currently dominant supporting structures for wind turbines. With the increase of the converter capacity, there is a great demand for higher supporting towers. However, structural vibrations in extreme wind events tend to become a major concern during tower design. To study wind turbine tower dynamics, an existing tubular steel tower was tested. Vibrational frequencies and damping ratios were identified. To avoid unexpected dynamic problems, a space frame steel tower has been proposed for supporting larger wind turbines. It is a structural system that can be assembled on-site by using prefabricated beams, columns, and brace members. A typical space frame steel tower was designed in this paper. Static loading, modal and buckling analyses of the tower were presented. It is expected to introduce engineers and designers more options for wind turbine tower design.

Climatological Study of Extreme Wind Events in a Coastal Area

2021 ◽  
pp. 59-74
Author(s):  
Damyan Barantiev ◽  
Ekaterina Batchvarova ◽  
Hristina Kirova ◽  
Orlin Gueorguiev
Keyword(s):  
Coastal Area ◽  
Extreme Wind ◽  
Wind Events
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