Research On Urban Thermal Field Remote Sensing Based On Somatosensory Comfort

In recent decades,with the rapid development of global urbanization,behind the prosperity of urban construction,human destruction of the natural environment has intensified.One is to blindly expand urban areas,occupy forest land,cultivated land and other land resources.The construction of various construction sites such as business circles,housing and transportation has caused a certain negative impact on the city 's ecological environment.The second is that the population growth rate is accelerated and the distribution is dense,the traffic volume is increased,and a large amount of exhaust gas is generated.These human factors increase the city 's heat island effect;the third is to supply the normal operation of urban life,which requires a large amount of non-renewable energy consumption.And in the process of burning fossil energy,a lot of heat will also be emitted.A large number of domestic and foreign researches on the heat island effect indicate that the coastal heat island is affected by factors such as sea and land winds,and the formation mechanism of urban heat islands is more complicated than that in the inland regions.The downtown area of Dalian is mainly carried by the functions of "Northeast Asia International Shipping Center" and "Northeast Central City",which has developed particularly rapidly in recent years.This article takes the main urban area(in the Zhong,Xi,Sha and Gan)of Dalian as the research area.Using GIS and RS technology,based on Landsat8 data with a total of 20 scenes in the five years from 2015 to 2019,combined with meteorological data,DEM data and land use data,using a single-window algorithm to retrieve the surface temperature,combining the human body comfort level with the urban heat island level From a perspective,the change law and spatial distribution characteristics of urban heat islands in the main urban area of Dalian in seasonal and inter-annual time scales are analyzed.The results are as follows:(1)At present,the concentration of thermal field in Dalian is significant.The surface temperature is increasing year by year,mainly in the middle temperature zone during the four seasons,and the human body feels comfortable in spring and autumn.In summer and winter,the human body will feel hot and cold and extremely uncomfortable.The area of the strong heat island area and the heat island area of the four seasons have increased slightly,and the area of the corresponding comfortable feeling area has also increased,replacing the original medium-temperature area with the largest proportion.The area of the cold island and the strong cold island area does not change much than in the four seasons,but the human body feels cold in the winter,which is extremely uncomfortable.The high temperature phenomena in the spring,summer and autumn thermal fields in Dalian are obvious.(2)In the horizontal space,take the remote sensing image center of the main urban area of Dalian as the quadrant center,divide Dalian into 8 quadrants,and analyze it;in the vertical space,take the Xi'an Road commercial district as the center,aiming at the thermal field and somatosensory level Analyze the relationship with the underlying surface by profile lines;the closer to the center and not near the sea,the area of the heat island area becomes larger and larger,and the more uncomfortable the human body feels;the farther away from the center and near the sea,the distribution of the low temperature zone and the sub-medium temperature zone The wider it is,the more comfortable the human body is;the heat island area of the study area is large and concentratedly distributed in the VII-IV area,and the human thermal sensation is also concentrated in this area,indicating that the urban development is too concentrated,and it should be appropriately transferred and rationally greened to reduce the heat island phenomenon.(3)In the urban internal structure,the temperature of the impervious underwater surface of the building land such as asphalt and cement is generally high,and the temperature of the thermal field of the underlying surface formed by natural factors,such as vegetation and water,is generally low.Therefore,it is recommended to build green parks,artificial lakes and other areas in the city that can regulate local high-temperature thermal fields,increase urban greening area,and appropriately reduce urban impervious surface expansion construction.High temperatures have a positive effect.