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Observed Thermal Impacts of Wind Farms Over Northern Illinois.

Slawsky LM, Zhou L, Baidya Roy S, Xia G, Vuille M, Harris RA - Sensors (Basel) (2015)

Bottom Line: The nighttime LST warming effect varies with seasons, with the strongest warming in winter months of December-February, and the tightest spatial coupling in summer months of June-August.Although the warming effect is strongest in winter, the spatial coupling is more erratic and spread out than in summer.These results suggest that the observed warming signal at nighttime is likely due to the net downward transport of heat from warmer air aloft to the surface, caused by the turbulent mixing in the wakes of the spinning turbine rotor blades.

View Article: PubMed Central - PubMed

Affiliation: Department of Atmospheric and Environmental Sciences, SUNY at Albany, Albany, NY 12222, USA. lslawsky@albany.edu.

ABSTRACT
This paper assesses impacts of three wind farms in northern Illinois using land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the Terra and Aqua satellites for the period 2003-2013. Changes in LST between two periods (before and after construction of the wind turbines) and between wind farm pixels and nearby non-wind-farm pixels are quantified. An areal mean increase in LST by 0.18-0.39 °C is observed at nighttime over the wind farms, with the geographic distribution of this warming effect generally spatially coupled with the layout of the wind turbines (referred to as the spatial coupling), while there is no apparent impact on daytime LST. The nighttime LST warming effect varies with seasons, with the strongest warming in winter months of December-February, and the tightest spatial coupling in summer months of June-August. Analysis of seasonal variations in wind speed and direction from weather balloon sounding data and Automated Surface Observing System hourly observations from nearby stations suggest stronger winds correspond to seasons with greater warming and larger downwind impacts. The early morning soundings in Illinois are representative of the nighttime boundary layer and exhibit strong temperature inversions across all seasons. The strong and relatively shallow inversion in summer leaves warm air readily available to be mixed down and spatially well coupled with the turbine. Although the warming effect is strongest in winter, the spatial coupling is more erratic and spread out than in summer. These results suggest that the observed warming signal at nighttime is likely due to the net downward transport of heat from warmer air aloft to the surface, caused by the turbulent mixing in the wakes of the spinning turbine rotor blades.

No MeSH data available.


Related in: MedlinePlus

Wind rose for for the sounding stations of KDVN (left) and KILX (right) from the annual (ANN) sounding composites observed ~80 m hub height (~293 m above sea level) at 12:00 GMT. The station surface elevation is 179 m for KILX and 230 m for KDVN. Wind rose displays the percentage, or frequency of wind directions and the winds from the north are at the top of the rose. The mean wind speed (m/s) is labeled at the end of each direction line.
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sensors-15-14981-f011: Wind rose for for the sounding stations of KDVN (left) and KILX (right) from the annual (ANN) sounding composites observed ~80 m hub height (~293 m above sea level) at 12:00 GMT. The station surface elevation is 179 m for KILX and 230 m for KDVN. Wind rose displays the percentage, or frequency of wind directions and the winds from the north are at the top of the rose. The mean wind speed (m/s) is labeled at the end of each direction line.

Mentions: The ~80 m hub-height wind directions from each sounding station at 12:00 GMT are plotted in Figure 11 and Figure 12 as seasonal composite wind rose to assess any shift in the spatial coupling. In general, the two sounding data show similar distributions of wind direction although the wind speed may differ slightly. The annual sounding composites have the strongest speeds and greatest occurrence of wind direction from the south, southwest and southeast (Figure 11).


Observed Thermal Impacts of Wind Farms Over Northern Illinois.

Slawsky LM, Zhou L, Baidya Roy S, Xia G, Vuille M, Harris RA - Sensors (Basel) (2015)

Wind rose for for the sounding stations of KDVN (left) and KILX (right) from the annual (ANN) sounding composites observed ~80 m hub height (~293 m above sea level) at 12:00 GMT. The station surface elevation is 179 m for KILX and 230 m for KDVN. Wind rose displays the percentage, or frequency of wind directions and the winds from the north are at the top of the rose. The mean wind speed (m/s) is labeled at the end of each direction line.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541818&req=5

sensors-15-14981-f011: Wind rose for for the sounding stations of KDVN (left) and KILX (right) from the annual (ANN) sounding composites observed ~80 m hub height (~293 m above sea level) at 12:00 GMT. The station surface elevation is 179 m for KILX and 230 m for KDVN. Wind rose displays the percentage, or frequency of wind directions and the winds from the north are at the top of the rose. The mean wind speed (m/s) is labeled at the end of each direction line.
Mentions: The ~80 m hub-height wind directions from each sounding station at 12:00 GMT are plotted in Figure 11 and Figure 12 as seasonal composite wind rose to assess any shift in the spatial coupling. In general, the two sounding data show similar distributions of wind direction although the wind speed may differ slightly. The annual sounding composites have the strongest speeds and greatest occurrence of wind direction from the south, southwest and southeast (Figure 11).

Bottom Line: The nighttime LST warming effect varies with seasons, with the strongest warming in winter months of December-February, and the tightest spatial coupling in summer months of June-August.Although the warming effect is strongest in winter, the spatial coupling is more erratic and spread out than in summer.These results suggest that the observed warming signal at nighttime is likely due to the net downward transport of heat from warmer air aloft to the surface, caused by the turbulent mixing in the wakes of the spinning turbine rotor blades.

View Article: PubMed Central - PubMed

Affiliation: Department of Atmospheric and Environmental Sciences, SUNY at Albany, Albany, NY 12222, USA. lslawsky@albany.edu.

ABSTRACT
This paper assesses impacts of three wind farms in northern Illinois using land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the Terra and Aqua satellites for the period 2003-2013. Changes in LST between two periods (before and after construction of the wind turbines) and between wind farm pixels and nearby non-wind-farm pixels are quantified. An areal mean increase in LST by 0.18-0.39 °C is observed at nighttime over the wind farms, with the geographic distribution of this warming effect generally spatially coupled with the layout of the wind turbines (referred to as the spatial coupling), while there is no apparent impact on daytime LST. The nighttime LST warming effect varies with seasons, with the strongest warming in winter months of December-February, and the tightest spatial coupling in summer months of June-August. Analysis of seasonal variations in wind speed and direction from weather balloon sounding data and Automated Surface Observing System hourly observations from nearby stations suggest stronger winds correspond to seasons with greater warming and larger downwind impacts. The early morning soundings in Illinois are representative of the nighttime boundary layer and exhibit strong temperature inversions across all seasons. The strong and relatively shallow inversion in summer leaves warm air readily available to be mixed down and spatially well coupled with the turbine. Although the warming effect is strongest in winter, the spatial coupling is more erratic and spread out than in summer. These results suggest that the observed warming signal at nighttime is likely due to the net downward transport of heat from warmer air aloft to the surface, caused by the turbulent mixing in the wakes of the spinning turbine rotor blades.

No MeSH data available.


Related in: MedlinePlus