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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

Areal mean MODIS nighttime LST anomalies (°C) between WFPs and NNWFPs (WFPs minus NNWFPs) for the period 2003–2013. The vertical reference line at the year 2010 indicates wind turbine construction completion for all three wind farms. The areal mean LST anomaly differences between the post- and pre-turbine construction periods (2010–2013 minus 2003–2006) are shown.
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sensors-15-14981-f006: Areal mean MODIS nighttime LST anomalies (°C) between WFPs and NNWFPs (WFPs minus NNWFPs) for the period 2003–2013. The vertical reference line at the year 2010 indicates wind turbine construction completion for all three wind farms. The areal mean LST anomaly differences between the post- and pre-turbine construction periods (2010–2013 minus 2003–2006) are shown.

Mentions: Figure 6 shows the areal mean seasonal and ANN time series of LST differences (WFPs minus NNWFPs) from 2003 to 2013. Despite a strong interannual variability, there is clearly a jump toward positive values across all seasons after 2010, when all the turbines came online, suggesting that the construction of wind turbines warm WFPs relative to NNWFPs. We can quantify the magnitude of the warming effect by subtracting the LST anomalies between the pre- and post-turbine construction period (2010–2013 minus 2003–2006). The warming rate is found to be the largest in DJF (0.39 °C), followed by MAM (0.27 °C) and SON (0.26 °C), and smallest in JJA (0.18 °C). The annual mean LST exhibits a warming effect of 0.26 °C.


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)

Areal mean MODIS nighttime LST anomalies (°C) between WFPs and NNWFPs (WFPs minus NNWFPs) for the period 2003–2013. The vertical reference line at the year 2010 indicates wind turbine construction completion for all three wind farms. The areal mean LST anomaly differences between the post- and pre-turbine construction periods (2010–2013 minus 2003–2006) are shown.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-14981-f006: Areal mean MODIS nighttime LST anomalies (°C) between WFPs and NNWFPs (WFPs minus NNWFPs) for the period 2003–2013. The vertical reference line at the year 2010 indicates wind turbine construction completion for all three wind farms. The areal mean LST anomaly differences between the post- and pre-turbine construction periods (2010–2013 minus 2003–2006) are shown.
Mentions: Figure 6 shows the areal mean seasonal and ANN time series of LST differences (WFPs minus NNWFPs) from 2003 to 2013. Despite a strong interannual variability, there is clearly a jump toward positive values across all seasons after 2010, when all the turbines came online, suggesting that the construction of wind turbines warm WFPs relative to NNWFPs. We can quantify the magnitude of the warming effect by subtracting the LST anomalies between the pre- and post-turbine construction period (2010–2013 minus 2003–2006). The warming rate is found to be the largest in DJF (0.39 °C), followed by MAM (0.27 °C) and SON (0.26 °C), and smallest in JJA (0.18 °C). The annual mean LST exhibits a warming effect of 0.26 °C.

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