| With the development of economy and the improvement of urbanization level,the city as a special ecological system and landscape on the surface of the earth,its comfort degree of the ecological environment has gradually become the focus of human attention.The urban climate is an important part of urban ecological environment,and is also the most prominent manifestation of human activities that are increasingly commonplace and deepen the impact of climate,which has attracted widespread attention.It is of great significance to correctly understand the characteristics of urban climate and to layout the city rationally,save energy and reduce consumption,develop harmoniously and build an ecological and civilized city.Linhe city as an important and core city in Inner Mongolia Hetao oasis,the urbanization in recent years of rapid development,city expansion speed increases,the underlying surface changes caused by climate change,not only affect their own sustainable development,but also affect the healthy of ecological environment and economic development speed,the Linhe city how to solve the climate characteristics.In this paper,Linhe city as the research object,based on the meteorological data of Hangjinhou county,Wuyuan and Linhe from 1984 to 2015.The climatic tendency,Morlet wavelet analysis and M-K test were used to analyze the climate in the vicinity of 32a.The population characteristics and the demographic data of 1989,1995,2000,2006,2010,2015 were used to study of Linhe city population,urban expansion,land use/cover change and the impact of urbanization on its urban climate.The main conclusions are as follows:?1?In recent 32 years,the average temperature,average wind speed and sunshine duration of Linhe City were increasing,while the precipitation and relative humidity decreased,with the tendency rates of 0.30?/10a,0.09m·s-1/10a,36.93h/10a,-9.13mm/10a,-0.47%/10a,respectively.?2?In recent 32 years,the heat island and dry island effect is obvious and the wind speed is less than the two counties in Linhe city from 1984 to 2010,and the dark island effect is obvious from 1994 to 2007,which summer heat island and dry island effect are the strongest between Linhe and Hangjinhou county in 2000s,while the dark island of winter was strongest from 1984 to 1989;the heat island effect is the strongest in 1990s,the dry and dark island showed strongest in 2000s and the winter heat island and dry island are the strongest between Linhe and Wuyuan county,while the strongest dark island effect is in summer;there is no rain island effect in Linhe city.?3?M-K mutation analysis showed that in 1986 which was a sudden change of mean temperature rise in Linhe city;the precipitation did not change significantly;the relative humidity reduced in 1994 and the average wind speed reduced in 1989;the sunshine duration increased suddenly in 2011.?4?Morlet wavelet analysis shows that the average temperature,precipitation,relative humidity and average wind speed of the Linhe city are the short cycles of 2a,and the dominant cycles of 5a,6a,7a and 8a.It indicates that the meteorological elements are affected by atmospheric circulation and El Ni?o.In addition,the average temperature and precipitation were also have significant cycles of 10a and 12a,respectively,they may also be affected by solar activity.There was no obvious period of sunshine duration.?5?The rapid expansion of the built-up areas,the increase of urban expansion speed and intensity,the rapid increase of population and the rapid increase of construction land in Linhe city have obviously exacerbated the urban heat island and dry island effect from 1984 to 2009.But the increase of forest land and waters in Linhe city and the expansion of built-up areas,the increase of expansion speed and intensity and the increase of population in nearby two counties and so on have weakened the heat island and dry island effect in Linhe city. |
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