Wind farms can cause wind speed attenuation and affect local temperature In order to reduce global warming, calls for the development of clean energy and renewable energy are increasing. Wind energy is an important aspect of clean energy. The utilization of wind energy resources has been extensively developed in many regions of the world, and more and more large-scale wind farms are being established and put into operation.

In the development of wind farm construction, people have done a lot of research on weather and climate conditions and the impact of climate change on wind farms. However, the role of everything is mutual. Will the construction of wind farms affect temperature, wind speed, and even climate change?

The wind farm slowed the downstream wind speed Professor Zhao Zongci of the Earth System Research Center of Tsinghua University stated that in recent years, some experts at home and abroad have used weather observation data to compare the meteorological elements before and after the construction of wind farms, and in the upstream and downstream regions of wind farms; Using climate models to simulate the local climate effects of wind farms, the impact of wind farms on local wind speeds was studied.

“It has been unanimously concluded at home and abroad that wind farms have a significant impact on the local wind speed, which will cause the downstream wind speed to decrease,” Zhao Zongci said.

Zhao Zongci took an observational data from a wind farm in Denmark as an example to illustrate the impact of wind farms on local wind speed. The wind speed entering this wind farm is 8 to 9 m/s. After absorbing the momentum through the operation of wind farms, the friction of wind turbines As a result, the wind speed observed in the downwind direction of the wind farm was significantly weakened, and the ratio of the wind speed at the downwind of 6 km to the original wind speed was 0.86, the ratio of 8 km downwind was 0.88, and the ratio of downwind 11 km was 0.90, although The increase in wind speed is slowly picking up, but it has not yet returned to its original level.

Some foreign scientists have used numerical simulation to confirm the attenuation effect of wind farms on wind speed. Jiang Wei, senior engineer of the China Meteorological Administration’s public weather service center, said that foreign scientists used a mesoscale model to set up 1, 9, and 36 wind farms within the scope of 900 square kilometers, and calculate the corresponding changes in wind speed at different locations. . The calculation results show that the effect of the wind farm results in a significant attenuation of the wind speed. The wind speed entering the wind farm is 8 to 9 m/s. After the wind farm is attenuated maximum, the wind speed is only 5 m/s, and the attenuation is kept within 20 km. As the far wind speed began to rise, the wind farms affected wind speed attenuation distances ranging from 30 km to 60 km.

The obvious change in local air temperature In addition to slowing the downstream wind speed, what impact does the local climate have? The scientists at home and abroad have concluded that the wind farm will change the downstream air temperature.

Prof. Zhao Zongci cited data from a wind farm in California, USA. The wind farm fan is 23 meters high and has 8.5 meters of blades. There are 41 rows and the distance is 120 meters. The wind towers at the upwind position and the downwind position of the wind farm provide daily air temperature observation data for the two months from mid-June to early August 1989.

“From the data point of view, the wind farm has a warming effect from 1 am to 7 am; during the day, it has a cooling effect from 13 am to 21 pm, and this effect is obvious,” said Zhao Zongci.

Jiang Yan said that foreign experts used the regional atmospheric simulation system and selected 306 simulation tests from the four seasons from 2008 to 2009. It is designed to add a small wind farm in the western part of the United States. There are 21 wind turbines. Each turbine is 100 meters high and its rotating blades are 100 meters in diameter. Using numerical model calculations, results that are basically consistent with the observed data are obtained.

What causes the wind farm's influence on the temperature? Why does this effect increase in temperature and sometimes reduce the temperature? Zhao Zongci explained that the wind farm has enhanced vertical mixing during work: the stable warm atmosphere of the night is above the cold layer. Enhance vertical mixing, causing warm air to go up and cold air goes up, resulting in near-surface warming; during the daytime, the cold air in the unstable atmosphere is above warm air, turbulence promotes mixing, cold air goes down and warm air goes up, causing near-ground cooling. The effect of wind farm temperature on the temperature depends on the stability of the atmosphere in the near-field, and the different stability causes the effect of the wind farm on the near-surface temperature or warming or cooling.

The impact on global climate change remains to be studied While studying the impact of wind farms on local climate, the impact of wind farms on global climate is another focus of domestic and foreign meteorological experts' research and debate. According to experts, some foreign numerical simulation studies show that the establishment and operation of large-scale global wind farms may have an impact on climate change. For example, it may cause an average global warming of 0.05°C to 0.73°C by the end of the 21st century, and the global wind speed may be significantly reduced, and it may cause other corresponding climate changes.

Jiang Ye said that some scientists abroad have used the two global atmospheric circulation models of the United States to set up wind farms in three wind energy-rich regions in central North America, Europe, and East Asia. Assuming that by 2100 the global use of wind energy accounts for more than 10% of total energy resources, Study the impact on the global climate. The numerical calculations lead to the conclusion that the impact of wind farms is not only local, but the impact of large-scale wind farm installations on global and intercontinental climate changes cannot be ignored. In particular, the influence of wind farms on the near-surface temperature in some areas can be Up to ±1°C to 2°C.

However, Zhao Zongci also admitted that research at home and abroad so far has been based only on the conclusion of the climate model. Because there are few studies on the impact of wind farms on global climate change, coupled with the uncertainty of climate models and the uncertainty of the design of wind farm simulation experiments, there are still many differences and disputes in the industry on the global climate effect of establishing wind farms on a large scale. More numerical tests and research are needed.

Since wind farms have a certain influence on the local climate, experts suggest that attention should be paid to the distance between wind farms in the construction of wind farms in order to reduce unnecessary mutual interference and influence between wind farms; The field needs to maintain a certain distance from the wind farm to ensure the accuracy of the meteorological observation data and not be disturbed by the wind farm. At the same time, the wind farm can be improved by transforming the fan to increase the efficiency of the wind turbine, and a wind farm with rich wind resources and suitable underlying surface can be selected to establish the wind farm. To reduce the impact of wind farms on local climate.

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