Resource Documents: Weather (25 items)
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Author: Armstrong, Alona; et al.
The global drive to produce low-carbon energy has resulted in an unprecedented deployment of onshore wind turbines, representing a significant land use change for wind energy generation with uncertain consequences for local climatic conditions and the regulation of ecosystem processes. Here, we present high-resolution data from a wind farm collected during operational and idle periods that shows the wind farm affected several measures of ground-level climate. Specifically, we discovered that operational wind turbines raised air temperature by 0.18°C and absolute humidity (AH) by 0.03 g/m³ during the night, and increased the variability in air, surface and soil temperature throughout the diurnal cycle. Further, the microclimatic influence of turbines on air temperature and AHd ecreased logarithmically with distance from the nearest turbine. These effects on ground-level microclimate, including soil temperature, have uncertain implications for biogeochemical processes and ecosystem carbon cycling, including soil carbon stocks. Consequently, understanding needs to be improved to determine the overall carbon balance of wind energy.
Alona Armstrong, Ralph R. Burton, Susan E. Lee, Stephen Mobbs, Nicholas Ostle, Victoria Smith, Susan Waldron, and Jeanette Whitaker
School of Geographical and Earth Sciences, University of Glasgow
Lancaster Environment Centre and Energy Lancaster, Lancaster University
National Centre for Atmospheric Science, School of Earth and Environment, University of Leeds
Centre for Ecology and Hydrology, Lancaster Environment Centre, Bailrigg
Environmental Research Letters 2016; 11: 044024
Download original document: “Ground-level climate at a peatland wind farm in Scotland is affected by wind turbine operation”
Author: Miller, Lee; and Keith, David
- Wind power reduces emissions while causing climatic impacts such as warmer temperatures
- Warming effect strongest at night when temperatures increase with height
- Nighttime warming effect observed at 28 operational US wind farms
- Wind’s warming can exceed avoided warming from reduced emissions for a century
We find that generating today’s US electricity demand (0.5 TWe) with wind power would warm Continental US surface temperatures by 0.24°C. Warming arises, in part, from turbines redistributing heat by mixing the boundary layer. Modeled diurnal and seasonal temperature differences are roughly consistent with recent observations of warming at wind farms, reflecting a coherent mechanistic understanding for how wind turbines alter climate. The warming effect is: small compared with projections of 21st century warming, approximately equivalent to the reduced warming achieved by decarbonizing global electricity generation, and large compared with the reduced warming achieved by decarbonizing US electricity with wind. For the same generation rate, the climatic impacts from solar photovoltaic systems are about ten times smaller than wind systems. Wind’s overall environmental impacts are surely less than fossil energy. Yet, as the energy system is decarbonized, decisions between wind and solar should be informed by estimates of their climate impacts.
Lee M. Miller, David W. Keith
School of Engineering and Applied Sciences, Harvard University, Cambridge, Mass.
Joule, Volume 2, Issue 12, P2618-2632, December 19, 2018. DOI: 10.1016/j.joule.2018.09.009
Download original document: “Climatic Impacts of Wind Power”
Analysis of near-surface relative humidity in a wind turbine array boundary layer using an instrumented unmanned aerial system and large-eddy simulation
Author: Adkins, Kevin; and Sescu, Adrian
Simulation and modeling have shown that wind farms have an impact on the near‐surface atmospheric boundary layer as turbulent wakes generated by the turbines enhance vertical mixing. While a few observational data sets that focus on near‐surface temperature changes exist, these studies lack high spatial resolution and neglect the combined effect of these temperature changes with an altered humidity profile. With a large portion of wind farms hosted within an agricultural context, changes to relative humidity can potentially have secondary impacts, such as to the productivity of crops. The goal of this study is to gather high‐resolution in situ field measurements in the wake of a single wind turbine in order to differentially map downstream changes to relative humidity. These measurements, obtained by an instrumented unmanned aerial system, are complemented by numerical experiments conducted using large‐eddy simulation. Observations and numerical results are in good general agreement around a single wind turbine and show that downstream relative humidity is differentially altered in all directions, specifically decreased below the turbine hub height. Large‐eddy simulation is then used to determine the effect of a large 7 × 4 turbine array on the relative humidity distribution in compounding wakes. It is found that the region of relative humidity decrease below the turbine hub height and the region of increase above the hub height both intensify, differentially extend in the lateral directions, and moves lightly upward with downstream distance.
Kevin A. Adkins, Department of Aeronautical Science, Embry‐Riddle Aeronautical University, Daytona Beach, Florida
Adrian Sescu, Department of Aerospace Engineering, Mississippi State University, Mississippi State
Wind Energy. DOI: 10.1002/we.2220
Author: Tang, Bijian; et al.
Wind farms (WFs) can affect the local climate, and local climate change may influence underlying vegetation. Some studies have shown that WFs affect certain aspects of the regional climate, such as temperature and rainfall. However, there is still no evidence to demonstrate whether WFs can affect local vegetation growth, a significant part of the overall assessment of WF effects. In this research, based on the moderate-resolution imaging spectroradiometer vegetation index, productivity and other remote-sensing data from 2003 to 2014, the effects of WFs in the Bashang area of Northern China on vegetation growth and productivity in the summer (June–August) were analyzed. The results showed that: (1) WFs had a significant inhibiting effect on vegetation growth, as demonstrated by decreases in the leaf area index, the enhanced vegetation index, and the normalized difference vegetation index of approximately 14.5%, 14.8%, and 8.9%, respectively, in the 2003–2014 summers. There was also an inhibiting effect of 8.9% on summer gross primary production and 4.0% on annual net primary production coupled with WFs; and (2) the major impact factors might be the changes in temperature and soil moisture: WFs suppressed soil moisture and enhanced water stress in the study area. This research provides significant observational evidence that WFs can inhibit the growth and productivity of the underlying vegetation.
Bijian Tang, Donghai Wu, Xiang Zhao, Tao Zhou, Wenqian Zhao, and Hong Wei
State Key Laboratory of Remote Sensing Science, Beijing Engineering Research Center for Global Land Remote Sensing, College of Remote Sensing Science and Engineering, Faculty of Geographical Science, Beijing Normal University; Joint Center for Global Change Studies (JCGCS), Beijing; State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University;
Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University; and Shaanxi Jinkong Compass Information Service Co., Xi’an, China
Remote Sensing 2017, 9(4), 332; doi: 10.3390/rs9040332
Download original document: “Observed impacts of wind farms on local vegetation growth in northern China”
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