| In recent years,many studies on the phenomenon of urban heat island showed that the characteristics of urban heat island(UHI)in coastal areas are different from those of inland areas due to the influence of sea breeze,and the formation mechanism of UHI is more complicated than that of inland areas.However,the climate conditions of coastal areas are superior than inland cities,its attention of UHI is low.This paper chooses Qingdao city which is a coastal city in the north of China as the object of study to analyse the temporal and spatial characteristics of its UHI.Qingdao city is an important economic center and port city in China,and the level of urbanization is high.Especially after the 1990 s,the scale of the city has expanded dramatically,Qingdao entered a new stage of development,which has led to a series of ecological responses,one of them is UHI.UHI has a direct impact on city’s housing,transportation,construction and people’s daily life,and even threaten the sustainable development of mankind as a whole,which aroused widespread concern.In this paper,we according to 416 roll of MOD11A2 remote sensing image of2001-2012 years,which is MODIS 8 days synthetic surface temperature product,taking UHIER index as the criteria and by using density segmentation method for the classification of land surface temperature,using the method of correlation analysis and spatial overlay analysis to analyze the spatial and temporal characteristics of UHI in Qingdao city.In addition,we discussed the influence factors of UHI combined with Landsat TM data,DEM data,statistical data and meteorological data.The main results were reached as follows:(1)The average annual temperature,the extreme minimum temperature and the extreme maximum temperature of Qingdao have been on the rise since the 1980 s,and the linear trend rate of change was respectively 0.289/10a、0.304/10a、0.407/10 a,and a sudden temperature change occurred at the end of the 1980 s.(2)The characteristic of UHI exhibits that it was stronger at night than daytime;The seasonal variation of UHI was strongest in winter and weakest in summer,the proportion of high-temperature area was respectively 8.66% and5.07%;On the annual scale,the phenomenon of UHI showing an increasing trend year by year,and the high-temperature area was increasing at the rate of 15% a year.(3)UHI mainly concentrate in urban area of Qingdao,south of Jimo,central of Jiaozhou and eastern of Huangdao,and the heart of UHI located at inland area in daytime,while it removed to the coastal area at night,and it appears northward trend year by year.In addition,by the analysis of landscape pattern of urban heat island,we find the surface temperature of Qingdao wasdeveloping to high temperature and centralized trend.(4)There was a negative correlation between NDVI and UHI,the land use types and topographic distribution were in good agreement with urban heat island distribution;The influence of human factors on urban heat island was shown as follows: Area GDP > Number of motor vehicles > Urban built-up area > Proportion of urban population;In terms of the meteorological conditions,wind direction and wind speed can affect the distribution and intensity of urban heat island respectively,while the relative humidity can weaken the urban heat island effect.This study can provide some basis and direction for UHI in Qingdao city.At the same time,it can enrich the theory of the UHI of coastal cities. |
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