With the frequent occurrence of haze in the Beijing-Tianjin-Hebei region, the saying that "the haze is basically controlled by the wind" has spread. At the same time, some media articles pointed out that "wind power and shelter forest construction caused the weakening of wind power in northern China", which also caused confusion for many readers: whether the development of wind power and afforestation will reduce the wind speed and is not conducive to removing haze? And Life "query related Chinese and foreign literature to see what foreign experts say?
Ground roughness weakens wind
In recent years, the wind in northern China has become smaller. This is not only the personal feelings of some friends. In fact, many scientific observations have also reached this conclusion. For example, in June 2012, the United States "Geophysical Research Newsletter" magazine stated that in the past 30 years in the middle latitudes of the northern hemisphere (China is located in this area), the surface wind speed has decreased by about 0.3 m / s. The research team of the researcher Mo Xingguo of the Institute of Geographical Sciences and Resources of the Chinese Academy of Sciences also found that the wind speed in the North China Plain has decreased significantly in the past 50 years.
In this regard, how much "responsibility" is required for the forest vegetation on the earth's surface? In 2010, the world-renowned British "Nature" magazine published a paper "Earth Science", and the author gave his own answer through research.
The paper is titled "Atmospheric Restability in the Northern Hemisphere Is Partly Attributable to Rough Surface". This article analyzes the data from 822 surface meteorological stations in the northern hemisphere from 1979 to 2008, and believes that the wind speed over the past 30 years has indeed become smaller in China, the Netherlands, the Czech Republic, and the United States.
Specifically, strong winds at the mid-latitudes of the northern hemisphere decay faster than weak winds, while wind speeds at high altitudes on the sea surface do not have this tendency. After analysis, the author believes that atmospheric circulation data can explain 10% to 50% of the causes of this phenomenon, and mesoscale data models show that surface roughness can explain 25% to 60% of the causes of this phenomenon. In Eurasia, the increase in surface roughness is mainly achieved through the increase of biomass (forest, grass, crops, etc.) and changes in land use patterns. In other words, the increase in forest vegetation and high-rise cities has reduced wind speed to a certain extent.
Wind farm raises nearby temperature slightly
The past 30 years have also been the 30 years of rapid development of green energy development around the world. Thousands of wind power towers stand up every year in the northern and middle latitudes of China, including China. They stand tall, use continuous wind to drive windmill blades to rotate, and the speed of rotation is increased by the speed increaser. Lift and drive the generator to generate electricity. After the wind passes the wind farm, the phenomenon of a decrease in speed does exist, but the impact of wind power on the environment is not as simple as everyone thinks.
The Journal of the American Academy of Sciences (PNAS) published an article in 2010 on the "Effect of Wind Farms on Surface Air Temperature", using data from California's famous Sangmanio Wind Farm to show that wind farms can affect the weather in its vicinity. The paper believes that the rotation of the fan blades increases the vertical agitation of heat and water vapor, which affects the meteorological conditions of the downwind direction. As a whole, the temperature at night near the wind farm rises slightly and the temperature during the day decreases slightly. However, the temperature rise was not significant. The British website Nature reports another advantage of this slight warming: it helps reduce frost near wind farms and prolongs the growth of crops in nearby areas.
A paper published on the Massachusetts Institute of Technology website in 2010 stated that through modeling, if wind power is used to supply 10% of global energy demand by 2100, the area where the wind turbine is installed will generate a temperature rise of 1 degree Celsius, and the temperature in other areas will increase. Rise less. This is because the rotation of the fan affects the atmospheric flow in the horizontal and vertical directions. The author Ron Poplin explained that there is no intention to oppose wind power construction: "We are not pessimistic about wind power, we have not thoroughly confirmed this impact, and hope that people will do more research in this area."
The impact of wind power on the environment outweighs its disadvantages
During the same period, experts and scholars also demonstrated that even if the wind farm weakened the surface wind to some extent, the impact was far less than its benefits. In 2004, the "Journal of the American Academy of Sciences" published the article "The Impact of Large Wind Farms on the Global Climate". The author used a model to study the impact of large wind farms, and believed that the impact of wind power on the global average surface temperature was minimal. In contrast, wind power reduces emissions of greenhouse gases and pollutants, which is a huge benefit.
In 2009, the American "Energy" magazine published an article entitled "Investigation on the Impact of Large Wind Farms on Atmospheric Energy" by two scholars, M. Maria and Marc Jacobs, of Stanford University. These two scholars estimated the losses caused by the construction of large-scale wind farms to global and regional atmospheric energy by establishing a momentum parameterization relationship between the wind turbine blades and the atmosphere. The results show that if wind power is used to supply global electricity ( Imagine the windmills), the global ground and low-level wind (atmospheric layer below 1 km) wind energy attenuation only 0.006% ~ 0.008%, the impact is minimal. On the other hand, the attenuation of ground wind energy caused by aerosol particle pollution caused by burning gasoline is much higher than 0.051% ~ 0.258%.
Finally, the impact of wind power and forests on climate is still being studied by the academic community. I believe that the conclusion will become clearer and clearer over time.