Characterization of Low-Level Winds of Southern and Coastal Delaware

Hughes, Christopher P.; Veron, Dana E.

doi:10.1175/jamc-d-14-0011.1

Cited by 9 publications

(16 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The wind speed at 10 m height, U 10 , obtained from the NAM product is consistent with measurements at NDBC station 44009 with normalized mean square error NMSE = 0.07 and b = 0.68 m/s, and

m =

0.89 for the regression

U_{10} [N D B C] = m U_{10} [N A M] + b

. As expected, NAM winds agree less with measured wind fields in the bay due to small‐scale spatiotemporal variability (Hughes & Veron, ). For example, for winds near station BRND1 (Figure ), we find NMSE = 0.22,

b =

2.12 m/s, and m = 0.92.…”

Section: Methodssupporting

confidence: 78%

“…The NMSE values are greater in the bay than on the shelf, which is expected because the wind vector is less accurate in the bay. In particular, the NAM wind product does not capture details of small‐scale wind variability in the upper bay (Hughes & Veron, ). Significantly smaller simulated H s occurs during observed short‐lived high wind events that the NAM wind does not capture.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Surface Wave Dynamics in Delaware Bay and Its Adjacent Coastal Shelf

et al. 2017

View full text Add to dashboard Cite

This study presents a broad overview of surface gravity wave dynamics in Delaware Bay and the adjacent continental shelf by employing the wave model Simulating Waves Nearshore one‐way coupled to the ocean model Regional Ocean Modeling System for a period from 2006 to 2012. The distributions of simulated wave statistics agree well with observations obtained from three wave buoys located on the shelf, in the bay near the open ocean, and about 35 km up the bay. A partitioning analysis to separate the two‐dimensional wave height spectrum into wind‐forced and swell parts reveals that waves on the shelf are predominantly remotely generated swell. Bathymetric refraction shelters the bay from energetic open ocean waves, which is supported by an idealized ray tracing analysis. Waves near the bay entrance are also refracted by oblique tidal currents, whose refraction characteristics critically depend on the detailed spatial distributions of the currents. Opposing tidal currents, flowing against the wave propagation direction, focus wave energy outside the bay entrance and in the deeper bay channels, where currents are relatively strong. A spectral partitioning analysis for waves in the bay indicates that less energetic wave fields are likely not directly forced by the wind. More energetic waves, on the other hand, are dominantly driven by winds and the wave response in the bay depends on the fetch‐setting wind direction. Our results for wind‐driven waves in the bay are consistent with previous fetch‐limited observations, but we find a systematic bias between wind and wave directions due to bathymetric refraction.

show abstract

“…The wind speed at 10 m height, U 10 , obtained from the NAM product is consistent with measurements at NDBC station 44009 with normalized mean square error NMSE = 0.07 and b = 0.68 m/s, and

m =

0.89 for the regression

U_{10} [N D B C] = m U_{10} [N A M] + b

b =

2.12 m/s, and m = 0.92.…”

Section: Methodssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Surface Wave Dynamics in Delaware Bay and Its Adjacent Coastal Shelf

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In addition, the summertime diurnal wind pattern and VWP shape variability may be influenced by additional mesoscale and microscale meteorological processes. For example, similar to results herein, inverted VWPs or extremely weak speeds were demonstrated during the late afternoon hours in the North Sea in addition to the New Jersey coastline, possibly related to the offshore component of the sea breeze circulation yielding a localized region of offshore divergence, weak low‐level winds, and eventually the strengthening of offshore southwesterly flow during early evening hours . The persistence of strong inflection VWP types offshore during southwesterly continental flow (short offshore fetch) combined with relationships to warmer offshore air temperature and higher surface stability, suggests that strong inflection types may also be related to the advection of warm continental air offshore, consistent with previous studies that note the development of offshore stable IBLs as drivers of atypical wind profiles in the Nantucket Sound and North Sea, including association with low‐level maximum wind profiles.…”

Section: Discussion Of Resultssupporting

confidence: 82%

“…This diurnal pattern of strongest wind speeds and available power in part coincides with summer electricity demand, peaking in the early evening when demand for cooling is highest. Further, stronger hub‐height winds correspond with a counterclockwise shift to southwesterly flow during early evening and overnight hours (21:00‐07:00 UTC), which may be related to local or regional thermally induced circulations such as the sea‐land breeze or nocturnal coastal LLJ, phenomena previously documented along the Eastern seaboard and the coast of Norway . In addition, the summertime diurnal wind pattern and VWP shape variability may be influenced by additional mesoscale and microscale meteorological processes.…”

Section: Discussion Of Resultsmentioning

confidence: 81%

“…As offshore turbines' size continues to increase, stretching into higher data‐void portions of the atmosphere, concerns remain about the appropriateness of using wind extrapolation techniques to understand the rotor‐layer wind resource and shear, and its consequential impact on the accuracy of preconstruction available power prediction. This is particularly true in a coastal environment, where less is known about the impact of atmospheric processes such as coastal low‐level jets (LLJs), offshore internal boundary layers (IBLs) and associated temperature inversions, coastal upwelling, and the offshore component of the sea breeze circulation on offshore rotor‐layer wind profiles and available power.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Classifying rotor‐layer wind to reduce offshore available power uncertainty

et al. 2018

View full text Add to dashboard Cite

Rotor-layer wind resource and turbine available power uncertainties prior to wind farm construction may contribute to significant increases in project risk and costs. Such uncertainties exist in part due to limited offshore wind measurements between 40 and 250 m and the lack of empirical methods to describe wind profiles that deviate from a priori, expected power law conditions. In this article, we introduce a novel wind profile classification algorithm that accounts for nonstandard, unexpected profiles that deviate from near power law conditions. Using this algorithm, offshore Doppler wind lidar measurements in the Mid-Atlantic Bight are classified based on goodness-of-fit to several mathematical expressions and relative speed criteria. Results elucidate the limitations of using power law extrapolation methods to approximate average wind profile shape/shear conditions, as only approximately 18% of profiles fit well with this expression, while most consist of unexpected wind shear. Further, results demonstrate a relationship between classified profile variability and coastal meteorological features, including stability and offshore fetch. Power law profiles persist during unstable conditions and relatively weaker northeasterly flow from water (large fetch), whereas unexpected classified profiles are prevalent during stable conditions and stronger southwesterly flow from land (small fetch). Finally, the magnitude of the discrepancy between hub-height wind speed and rotor equivalent wind speed available power estimates varies by classified wind-profile type. During unexpected classified profiles, both a significant overprediction and underprediction of hub-height wind available power is possible, illustrating the importance of accounting for site-specific rotor-layer wind shear when predicting available power. KEYWORDS atmospheric stability, coastal meteorology, Doppler wind lidar, offshore wind resource, rotor equivalent wind speed, turbine available power INTRODUCTIONOffshore wind (OSW) power provides an enormous clean electricity resource to help mitigate anthropogenic climate change and stimulate the economy. There is a significant opportunity to generate OSW power since most of the global resource is untapped with 90% of the 12 GW installed capacity worldwide concentrated in the relatively small geographic region of Northern Europe. 1 Global investment in OSW development reached a record high in 2016, signaling an important transition in the industry toward accelerating expertise 2 ; however, preconstruction energy yield uncertainty is a reoccurring challenge that contributes to significant project risk and could delay the technology's cost competitiveness. 3Inaccuracies in estimating turbine performance prior to wind farm construction contributes to preconstruction energy yield uncertainty. 3 It is well known that vertical wind speed shear across a turbine's rotor layer contributes to power performance uncertainty (eg, previous studies 4-8 ). To help reduce this uncertainty, a rotor equivalent wind speed (REW...

show abstract

Effects of Locally Generated Wind Waves on the Momentum Budget and Subtidal Exchange in a Coastal Plain Estuary

2019

View full text Add to dashboard Cite

A numerical model with a vortex force formalism is used to study the role of wind waves in the momentum budget and subtidal exchange of a shallow coastal plain estuary, Delaware Bay. Wave height and age in the bay have a spatial distribution that is controlled by bathymetry and fetch, with implications for the surface drag coefficient in young, underdeveloped seas. Inclusion of waves in the model leads to increases in the surface drag coefficient by up to 30% with respect to parameterizations in which surface drag is only a function of wind speed, in agreement with recent observations of air‐sea fluxes in estuaries. The model was modified to prevent whitecapping wave dissipation from generating breaking forces since that contribution is integrally equivalent to the wind stress. The proposed adjustment is consistent with previous studies of wave‐induced nearshore currents and with additional parameterizations for breaking forces in the model. The mean momentum balance during a simulated wind event was mainly between the pressure gradient force and surface stress, with negligible contributions by vortex, wave breaking (i.e., depth‐induced), and Stokes‐Coriolis forces. Modeled scenarios with realistic Delaware bathymetry suggest that the subtidal bay‐ocean exchange at storm time scales is sensitive to wave‐induced surface drag coefficient, wind direction, and mass transport due to the Stokes drift. Results herein are applicable to shallow coastal systems where the typical wave field is young (i.e., wind seas) and modulated by bathymetry.

show abstract

Characterization of Low-Level Winds of Southern and Coastal Delaware

Cited by 9 publications

References 46 publications

Surface Wave Dynamics in Delaware Bay and Its Adjacent Coastal Shelf

Surface Wave Dynamics in Delaware Bay and Its Adjacent Coastal Shelf

Classifying rotor‐layer wind to reduce offshore available power uncertainty

Effects of Locally Generated Wind Waves on the Momentum Budget and Subtidal Exchange in a Coastal Plain Estuary

Contact Info

Product

Resources

About