Remote Sensing Monitoring Of Urban High Temperature And Heat Wave Phenomenon Based On Multi-source Data

Under the background of global warming,with the accelerating urbanization process,the urban heat island effect is becoming more and more serious,and extreme high temperature events are frequent,which makes the urban climate problem increasingly prominent.It has a serious negative impact on the health of urban residents and the economic development.Therefore,the monitoring and research of heat wave phenomenon is particularly important to reduce the negative impact of extreme high temperature events on human health,improve human living environment,and promote the sustainable development of cities.Temperature is an important meteorological index for analyzing climate change and high temperature monitoring,while the number of weather stations in less,the multi-factor statistical analysis method based on remote sensing data is used to obtain near-surface temperature space with high time resolution and strong spatial continuity.The monitoring of high temperature heat wave phenomenon is of great significance.This paper will estimate the near-surface temperature based on the historical temperature data measured by weather stations and MODIS satellite remote sensing data.On this basis,combined with air relative humidity data,the torridity index and the heat wave index are selected as the comprehensive evaluation indicators for the high temperature heat wave phenomenon.Monitor the high-temperature heat wave phenomenon in Chongqing from July24,2013 to July 31,2013,and analyze the time,regularity,area,range,intensity and spatial distribution of the high-temperature heat wave during this period.Combined with the human body comfort index,extract the high temperature heat wave period,the area where the human body feels sultry and extremely sultry in the high temperature heat wave area.In order to analyze the impact of high temperature heat wave on human health and comfort.In the study,two methods are used to estimate near surface temperature.One is multi-factor statistical analysis based on remote sensing data and the other one is ordinary Kriging interpolation method.In the process of establishing near surface temperature estimation model,this paper introduces surface temperature(LST)and surface albedo(Albedo),Normalized Vegetation Index(NDVI),Digital Elevation Model(DEM)and latitude data.They are used as the basic parameters of the model.This article uses the estimation results of three time periods using multi-factor statistical analysis methods based on remote sensing data and ordinary Kriging interpolation method.The estimation results of the two methods are compared with the actual measured temperature.The average absolute error and the root mean square error are used to verify the overall estimation accuracy of the two methods,The inversion accuracy of the two methods is compared and analyzed.The comparison and analysis of the inversion accuracy of the two methods show that the inversion accuracy of the two methods is not significantly different,but in the presentation of the difference in near-surface temperature within the region and between urban and rural areas,the method of near-surface temperature estimation based on multi-factor statistical analysis of remote sensing data is obviously better than the ordinary Kriging interpolation method.The range of the average absolute error between the estimation result of the multi-factor statistical analysis method based on remote sensing data and the actual temperature measured at the station is between 1.13?-1.40?,and the root mean square error range is between 1.46?-1.80?;Finally,based on the near-surface temperature estimated by the multi-factor statistical analysis method of remote sensing data,the daily spatial distribution data of near-surface temperature in Chongqing and its change rule over time are obtained.The range,intensity,area and spatial and temporal distribution of heat wave in Chongqing are analyzed by using torridity index and heat wave index.The typical areas representing different land cover types are selected for analysis,and the spatial distribution of human comfort in heat wave area is analyzed in combination with the human comfort index,so as to extract the period of heat wave,the areas where people feel hot and extremely hot in heat wave area.The results show that the variation trend of near-surface maximum temperature,human comfort index,torridity index and heat wave index in Chongqing are roughly the same over time.The intensity of heat wave in the study area is mainly in the range of mild heat wave and moderate heat wave.The heat waves in the study area are mainly concentrated in mild heat waves and moderate heat waves.And the range of high-temperature heat waves expands first and then decreases over time.This paper analyzes the impact of heat wave on human comfort with the help of human comfort index,and concludes that the human comfort level of Chongqing high temperature heat wave area during this heat wave period is from 7 to 9.The degree of human comfort is respectively: hot,stuffy,extremely stuffy,that is,in the heat wave area,the human body is in an uncomfortable state.The human body will feel extremely stuffy and uncomfortable in these areas during heat waves.People should try not to go to these areas.If you go to these areas,you must be well protected,all physical activities should be avoided as much as possible to prevent heat stroke.Therefore,people should arrange outdoor activities reasonably during periods of heat wave.