Research On The Temporal And Spatial Laws And Control Methods Of Kunming's Urban Heat Island Effect

It has been a period of rapid economic development in Kunming for nearly 30 years.With the rapid expansion of urban scale and the increase of urban population,the urban ecological environment problem--urban heat island effect has also emerged.Studying the Spatiotemporal law and regulation method of urban heat island effect in Kunming has certain reference value and guiding function to the urban sustainable development planning and ecological civilization construction in the future Kunming.Based on the surface temperature inversion of 12-view Landsat series data from 1988 to 2018 in the 30 years of Kunming,this paper studies the interannual and monthly characteristics and changes of land surface temperature distribution in Kunming with spatial superposition analysis,transfer matrix and principal component analysis,and aims at the relationship between surface index and urban heat island intensity,The change of land use type,the relationship between surface temperature and land use type are analyzed and studied.The main conclusions are as follows:(1)Temporal and spatial law of urban heat island in Kunming,from 1988 to 2018,the urban heat island of Kunming was significantly enhanced and the urban expansion was obvious,gradually formed in the "northwest-southeast" and "Southwest-northeast" direction distribution of urban heat island areas.For the selected four months,the urban heat island effect was the strongest in February,with the proportion of the area of the high-temperature area being 7.59%,and the weakest in August,with the proportion of the high-temperature area being 4.40%.(2)The correlation between surface temperature and surface index,soil regulation vegetation index,soil moisture index and surface temperature showed a negative correlation;bare soil index,normalized building index and surface temperature showed positive correlation.(3)The relationship between surface temperature and land use type,in four kinds of land use types,the average geothermal temperature of bare land is the highest,followed by construction land and green space,the average geothermal temperature of water body is the lowest.In the influence of land use type change on surface temperature,urban construction land and bare land will increase the surface temperature rise,while vegetation and water body will inhibit the increase of surface temperature.(4)Analysis of the causes of urban heat island,through the principal component analysis of six indexes of humanities and nature,it is found that population density,building scale and bare soil index contribute to urban heat island,among which the contribution of population density is low,and the ground elevation,surface vegetation and water environment have inhibitory effect on urban heat island,Among them,the role of water environment is weaker.Finally,combining with the above conclusions,this paper puts forward the corresponding control methods for the current problems of urban green space,urban water body and urban construction land in Kunming,expecting to be helpful for the future development planning of kunming.