Experimental Study On Low-altitude Infrared Remote Sensing Used In Urban Thermal Environment In Hot And Humid Zone

Surface temperature of land is an effective indicator in research of urban outdoor thermal environment.To research urban micro-scale outdoor thermal environment ,it is important significance for application of low-level infrared remote sensing systems to obtain urban outdoor surface temperature of land. In this thesis,the experimental research is the main technical. Research focus of this thesis is the feasibility of the low-altitude infrared remote sensing system to obtain accurate surface temperature of outside land in the city, and the calibration and analysis of the low-level infrared remote sensing image also is the study contents of the thesis . This thesis mainly undertook the following work:(1) The low-level infrared remote sensing system consist of unmanned airship,thermal infrared imager and common digital camera. Experiment show that ,on the condition of 250m high, average speed 9m/ s, the largest offset distance of the route from the side is 40m, the average offset distance of the route is 4.7m,the biggest changes of the actual flight height is10m, compared to the default route height , the average changes of the route height above the aircraft is 5.1m,.(2) Carried out continuous observations of the water,shale brick floor,concrete floor,white tile floor,asphalt pavement. Experimental results show that:the average surface temperature of each measuring point respectively is, the water 30℃, shale brick floor 43.5℃, concrete floor 47℃, white tile floor 38.5℃,asphalt pavement 49.5℃.The average surface temperature fluctuation of the measuring point are less than 1℃, in which water surface temperature fluctuation is less than 0.5℃(3) In the test area,carried out simultaneously low altitude remote sensing experiment and ground-based observations experiment, the results obtained are as follows: completed 10 flight routes, get 370 infrared remote sensing,390 visible light remote sensing. During flight, the biggest changes of the actual flight height is145m, compared to the default route height , the average changes of the route height above the aircraft is 49.7m, the largest offset distance of the route from the side is 64m, the average offset distance of the route is 10.1m.(4) Carried out the processing of geometric correction and mosaic treatment obout infrared remote sensing obtained in the experiment, get the whole infrared remote sensing image of the test region, the image spatial resolution is still 0.6 mrad, with temperature information preserved well;In the test area,Carried out simultaneously low altitude remote sensing experiment and ground-based observations experiment,and carried out the calibration processing of low altitude remote sensing image.(5) According to low-level infrared remote sensing image after calibration, study outdoor thermal environment of test area. The study includes plane distribution of the surface thermal field,surface temperature distribution of typical underlying surface,the temperature profile distribution of thermal field.The results show that: Hard impervious land surface for urban outdoor thermal environment has apparent warming effect, green space, water and other surface for urban outdoor thermal environment has apparent cooling effect.This thesis introduce low-level infrared remote sensing system used to study urban micro-scale outdoor thermal environment.This thesis provided a reference for the intensive study on the multi-scale thermal environment of city in hot and humidity zone.