染雾Hard state of the urban canopy layer 篇一
Urbanization has brought about significant changes to the environment, particularly in terms of the urban canopy layer. The urban canopy layer refers to the layer of vegetation that exists within cities and towns, including trees, shrubs, and other forms of greenery. However, the state of the urban canopy layer is currently facing numerous challenges, leading to a hard state that needs to be addressed.
One of the main factors contributing to the hard state of the urban canopy layer is the rapid expansion of urban areas. As cities grow and develop, more land is needed for buildings, infrastructure, and housing. This often results in the removal of existing vegetation, leading to a loss of green space and a reduction in the urban canopy layer. The lack of space for trees and other plants to grow and thrive in urban areas further exacerbates the hard state of the urban canopy layer.
Another significant challenge facing the urban canopy layer is pollution. Urban areas are known for their high levels of air and water pollution, which can have detrimental effects on the health and growth of vegetation. Air pollution from vehicles and industrial activities can lead to the accumulation of harmful chemicals on leaves, inhibiting photosynthesis and reducing the overall health of trees and plants. Similarly, water pollution from runoff and contaminated irrigation can negatively impact the urban canopy layer, making it difficult for vegetation to survive and flourish.
Furthermore, climate change poses a significant threat to the urban canopy layer. Rising temperatures and changing weather patterns can affect the growth and survival of trees and plants in urban areas. Heatwaves and droughts, which are becoming more frequent and intense due to climate change, can cause stress and even death in vegetation. Additionally, extreme weather events such as storms and hurricanes can cause physical damage to trees and disrupt the overall balance of the urban canopy layer.
To address the hard state of the urban canopy layer, various measures can be taken. Firstly, urban planning should prioritize the preservation and expansion of green spaces within cities. This can include the creation of parks, gardens, and green roofs, as well as the implementation of green building standards. Additionally, efforts should be made to reduce pollution levels in urban areas, including stricter regulations on emissions and improved waste management practices. Lastly, adapting to and mitigating the impacts of climate change is crucial for the survival of the urban canopy layer. This can involve planting climate-resilient tree species, implementing irrigation systems, and developing urban heat island mitigation strategies.
In conclusion, the urban canopy layer is currently in a hard state due to factors such as urban expansion, pollution, and climate change. However, by prioritizing green spaces, reducing pollution, and adapting to climate change, it is possible to improve the state of the urban canopy layer and create healthier and more sustainable cities.
Hard state of the urban canopy layer 篇三
Hard state of
It is found by experiment that under the thermal convection condition, the temperature fluctuation in the urban canopy layer turbulence has the hard state character, and the temperature difference between two points has the exponential probability density function distribution. At the same time, the turbulent energy dissipation rate fits the log-normal distribution, and is in accord with the hypothesis proposed by Kolmogorov in 1962 and lots of reported experimental results. In this paper, the scaling law of hard state temperature n order structure function is educed by the self-similar multiplicative cascade models. The theory formula is Sn = n/3μ{n(n+6)/72+[2lnn!-nln2]/2ln6}, and μ Is intermittent exponent. The formula can fit the experimental results up to order 8 exponents, is superior to the predictions by the Kolmogorov theory, the β And log-normal model.
作 者： HU Fei CHENG Xueling ZHAO Songnian QUAN Lihong 作者单位： LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China 刊 名：中国科学D辑（英文版） SCI 英文刊名： SCIENCE IN CHINA SERIES D(EARTH SCIENCES) 年，卷(期)： 200548(z2) 分类号： P4 关键词： atmospheric boundary layer urban canopy layer atmospheric turbulence turbulence cascade