04/18/23 Air Resources Laboratory

Boundary –Layer Dispersion

NOAA/ATDD - Duke EnergyCooperative Research and Development

AgreementJoint Wind Energy Program:

Atmospheric Velocity Gradients

Will Pendergrass

NOAA/ARL/ATDD

OAR Senior Research Council Meeting

Oak Ridge, TN

August 18-19, 2010

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(1) Can the forecast of wind turbine hub-height wind speeds be improved through inclusion of near-neutral and unstable flux-gradient wind modeling techniques?

(2) What is the uncertainty associated with high resolution WRF mesoscale in both now-cast and forecast of winds at 10 m and hub-height?

(3) Does assimilation of surface energy flux measurements (heat flux, shear stress, surface roughness ,

displacement height, and mixed layer height) improve mesoscale forecasts through mesoscale model land surface exchange methodologies?

(4) What is the impact of spatial variability in surface energy-balance on forecasted gradient winds at 10 m and hub-height?

Science Questions

NOAA/DUKE CRADA

Goal: Improved Forecasts of Hub Height Winds

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NOAA/DUKE CRADA

Forecast Confidence Level

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field measurementsmesoscale modeling

Phase one (1) is an evaluation of the flux gradient velocity profile technique based on directly measured surface energy balances.

Phase two (2) is an evaluation of results from Phase one as implemented in the WRF model through alternative land use model parameterizations.

Boundary-Layer Velocity Gradient Program

NOAA/DUKE CRADA

Velocity Gradient Profile

Monin-Obukov Stability

04/18/23 Air Resources Laboratory

Based on conversations between NOAA/ATDD and Duke Energy, the Ocottilo wind farm was selected as the initial focused study area. During a joint site survey, NOAA/ATDD and Duke Energy engineers evaluated the Ocotillo area for installation of a NOAA 10-meter energy balance system and 30-meter wind/temperature profiling system. Additional siting was evaluated for Doppler SODAR operation, additional surface based energy-balance system, and possible radiosonde operations.

SiteSelection

Big Spring, Texas

DukeEnergy

Ocotillo Wind Farm

NOAA/DUKE CRADA

Prevailing winds

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In cooperation with Duke Energy field engineers, NOAA/ATDD install a 30-meter tower monitoring winds and temperature within the surface roughness layer.

Wind FluxProfiling Tower

Acquired Observations

15, 30, 60 minute outputu, v, w, ws, wdσu, σv ,σw, u’v’,u’w’, v’w’, T, T’2, w’T’,u’2, v’2, w’2, u run, v run, w run

NOAA/DUKE CRADA

04/18/23 Air Resources Laboratory

In cooperation with Duke Energy field engineers, NOAA/ARL installed a 10-meter energy balance monitoring system

NOAA/DUKE CRADA

15, 30, 60 minute outputu, v, w, ws, wdσu, σv ,σw, u’v’,u’w’, v’w’, T, T’2, w’T’,u’2, v’2, w’2, u run, v run, w run,soil temperature (5 levels), soil moisture, solar energy components, surface temperature, CO2/H2O

Surface Energy Balance system

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NOAA/ATDD established a web-based data management site to provide both NOAA/ATDD and Duke Energy with access to acquired measurements from both the Energy balance system

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NOAA/DUKE CRADA

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WRF Model OutputNOAA/DUKE CRADA

04/18/23 Air Resources Laboratory

NOAA/DUKE CRADA

Gradient profile Requirements:

U*, z0, h, z/L

Observed Duke EnergyOcotillo 80 m winds

Evaluated Ocotillogradient profileparameters

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NOAA/DUKE CRADA

Intercomparison of

forecast/measured winds and temperatureRTMA – red

ATDD - black

Wind Speed

Wind Direction

Temperature

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•Technical Interchange Meetings (TIMs) : Researchers from NOAA/ARL and Duke Energy have planned routine (TIMs) to review collaborative efforts (next meeting late September, 2010).

•Evaluation/comparison of measured Duke Ocotillo 80-meter winds using measured e-balance surface winds and boundary layer variables using basic velocity gradient profile methodologies.

•Evaluation/comparison of measured Duke Ocotillo 80-meter winds using RTMA and WRF forecast surface winds and boundary layer variables using evaluated basic velocity gradient profile methodologies.

•Late Summer-2010 study intensive – measurement of vertical profiles using Doppler Sodar, evaluation of CTW lidar, and high frequency spectral wind measurements.

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Next Steps

NOAA/DUKE CRADA