An Study Of The Mechanism Of The Urban Heat Island Formation,evolution And Planning Strategies

With the rapid development of China’s urbanization, expanding built-up area,and single urban area continuing to expand, cities and towns are in the pursuit ofhigh-rise. High-rise buildings in the small town become the norm and big cities arebecoming forest reinforced concrete. Along with this is the growing urban heat island(UHI),2013summer, the major cities have burst continuous high temperature events:"roast fish on the road," died of heat stroke illness, and more often to break the hightemperature limit. Since Copenhagen climate conference, the carbon emissionreduction pressures is growing. China’s carbon emissions has been ranked second inthe world, and its main carbon emissions mainly from urban areas, some of whichcomes from the UHI effect. UHI effect is largely due to the irrational bring urbanspace, which includes urban form layout, develop strength, green water, hardenedground and other factors.Based on3S technology and ground-based observation platforms, and the use ofartificial intelligence theory, landscape ecology, meteorology, cellular automata, etc.,this dissertation researches on the UHI in the main city and center city of Tianjin.Research data used mainly as: multi-period landsatTM satellite remote sensing images,Pléiades0.5sub-meter satellite imagery, Tianjin map, Tianjin1:2000electronic map,master plan map of Tianjin, Tianjin topographical maps. Among them, the measureddata covering the main urban,6suburban meteorological stations,18downtownmonitoring points, a total of24monitoring points. The main considerations of thelayout of the monitoring points are time, weather conditions, floor area ratio, buildingdensity, water, green spaces, buildings and trees cover the impact of road vehicleexhaust, the number of sites layout, testing requirements and other internationalstandards.The dissertation made an inversion of surface temperature and measured temperature correction data based on IB, and analyzed the characteristics of UHIlandscape pattern of evolution and human thermal comfort affected spatial patterntransfer. Concluded as follows:①constructed grading standard surface UHI ofthermal comfort impacts, as the scientific division of the UHI intensity and analysis ofsurface UHI impact, providing a way of thinking and the standard basis, in order toreduce the summer UHI affect provides a space for grading partition adjust thereference standard;②the thermal comfort in Tianjin affected by surface UHIcontinues to expand, growing impact strength, high impact zones continue to gatherstrength to expand;③the second thermal comfort affected zones becomefragmentation gradually; the area of the largest patch decreases. The pattern of largecentralized been greatly weakened, large patch growth goes to the urban fringe with atotal area experienced a partial U-liter changes after the first drop, the overall trendof increasing the area occupied;④the third, fouth and fifth affected zones, thenumber and density of patches increasing, showing a scattered island-like, spatiallocation and frequent changes, in the migration to the northeast and the northernsuburbs of expansion, the total area and the largest patch area is also increasingrapidly;⑤landscape patch fragmentation, patch type mixture, patch area connectivityintense UHI reduction, the promotion of air flow and heat transfer surface high andlow range, reduced UHI, improve human thermal comfort plays an important role;⑥residential high-rise building, the thermal comfort deteriorate significantly increasethe area and make a serious local thermal comfort level increased, while theconstruction of multi-storey residential increase human comfort;⑦group of urbanspace expansion, heat islands can fragment each other forum type segmentation andfragmentation, thereby slowing the UHI effect.By weakening urban form layout parameters and analyzing responsemechanisms UHI, we have a clear understanding of UHI intensity and urban form ofthe area, dispersion, approaching degree, fractal dimension and shape indexmechanism. By studying it, the dissertation concludes the following conclusions:①proposed the concept of a dual-index algorithm UHI intensity, the highest UHIwarming and UHI warming gross; found the effective measure to solve the problem of UHI intensity, both expressed appreciation to bring the highest temperature UHIeffect, but also indicates how much UHI measurement problems caused increasedheat;②UHI intensity increases as the total area of urban form; the equation of thehighest form of UHI warming and the total area of the city is Y=0.008x+6.4, and theUHI warming gross equation is Y185.5x36050;③UHI warming gross andUHI form degree are of close linear relationship, with COHESION ’s equation is Y=241900x-24030000, with DIVISION ’s equation is Y=-1435000x+1455000, andMESH ’s equation is Y=6.897x+19570, and AI ’s equation is Y=28140x-2460000;④UHI intensity with patch area increases, the regression equation of patch areaswhich are more than50km2and maximum UHI warming gross is: Y=0.0103x+7.42;the equation of patch area and UHI warming gross is: Y=0.1969x2+53.94x+603.2.⑤UHI intensity ratio of the circumference of the area, perimeter area ratio and thehighest UHI warming equation isY e(0.7740.0256/x), when the perimeter to arearatio is [0.005,0.04], its total UHI warming equation is: Y=2.4821011x4-2.7151010x3+1.074109x2-1.82107x+1.116105;⑥UHI intensity increaseswith increasing fractal dimension, fractal dimension and the highest UHI warmingregression equation, fractal dimension and the total UHI warming equation is:Y=1.139107x3-3.988107x2+4.632107x-1.785107.Based on the measured data and high image resolution data, the dissertationfocuses on the plot rate, spatial scale sensitivity building density, green rate, water,and other factors hardened ground, and the key parameters of the formation of spatialand temporal characteristics and layout of the UHI and so on. By studying, weconclude the following conclusions:①proposed core plot rate, the concept ofideological core building density, core green rate, core water rate, the rate of corehard surface and made a sensitive issue search method using moving window andscales;②the most sensitive scale radius of core plot rate is230m, floor area ratioand core daytime UHI intensity is positively related to the conversion from negativecorrelation to positive correlation between the main afternoon.10:30,11:00,14:30-16:30correlation coefficients, exceeding0.05confidence level test. Regression curve showed that: the average core plot rate for each additional one morning UHIintensity decreased0.76℃; the afternoon UHI intensity increased by0.97℃.③most sensitive core building density scale radius is130m. The relationship of daytimebuilding density and UHI intensity is from the negative correlation to positivecorrelation.9:00-11:00correlation coefficients were more than0.04confidence leveltesting, regression equation showed that: the average increase of0.1per buildingdensity, UHI intensity decreased0.46℃.④most sensitive core green rate scale radiusis15m. Effects of green space on the UHI, mainly played a very important role instabilizing the daytime high temperature UHI peak morning faint enhanced UHI, astrong reduction of the UHI afternoon. Correlation between14:00-16:00core greenrate and UHI intensity than the confidence level of0.05. Regression equation showedthat: the average rate per core green10%increase in UHI intensity decreased0.18℃.⑤distance to the surface from an average increases100m, the temperature rises0.78℃. Gradient cooling efficiency classification of water bodies of different widthsof68.5m,146m,311m,670m and1430m.⑥most sensitive core scale water ratescale radius is200m.11:30-15:30, water rates associated with core UHI intensity, theconfidence level of0.05over the test. Regression analysis found that: the averagecore10%increase in water rates, UHI intensity decreased2.3℃. core water rate andthe average daytime UHI intensity regression equation is;⑦hardened ground mostsensitive scale is15m. Daytime core hardface rate and UHI intensity is alwayspositive correlation between enhanced strongest influence in the afternoon. Amongthem, the correlation coefficient12:00,13:00,14:00of more than0.05confidencelevel test. Regression analysis found that: the average rate per core hardface10%increase in UHI intensity decreased0.22℃. Core hardface rate and the averagedaytime UHI intensity fitting equation is: y=1.54x+2.45.In order to achieve the UHI data management, UHI intensity simulations predictthat the UHI univariate warning function, this study uses the C#language based onMicrosoft Visual Studio2010.NET development environment, the development ofUHI simulation forecast and early warning information system. The system is able tocomplete the UHI intensity space simulation predicts that the rate of volume, surface hardening UHI warning, guiding spatial layout green, water optimization. Systemdeveloped in this study also implements an independent library: OPERBASE class,TXTOPER class.By principal component analysis, the scale is half the force factors influencingfactors, that is to say, if the layout of factors affecting UHI is not proper, it willmake a negative impact on the UHI increased by50%.Using the author developed CA panel UHI simulation software and the UHIsimulation forecast and early warning information systems, simulation and predictionof spatial distribution pattern of the UHI, as well as single factors affecting UHIspatial pattern. The results showed that:①plot rate of UHI warning center city atotal of two grades of yellow and orange, yellow warning zone accounted for28%,accounting for16.5%of the orange alert, showing "two cores, two belts " patterncharacteristic space;②status of green areas severe patch fragmentation, coolingbetter patch presented island in the central city, there is no space corridor and coolingsystems;③water cooling mainly concentrated in the south, the biggest impact is theconvergence of the Haihe River in the central city, but the two sides formed a veryobviously cold corridor; and the high temperature on both sides of the river Wei JinRiver, four modernizations River, Yueya River; Haihe River, Xinkai River, ZiyaRiver and North Canal constitute four radiation cooling corridor;④Status hardenedground warming pattern, the overall decentralized, local concentration, all of theseshow "one belt, six-core" pattern space.Comprehensive analysis of spectra by the status quo UHI effects of factors, andaccording to the Tianjin summer temperatures characteristic body temperaturephysiological response, the relevant state regulations, etc., the dissertation presentedthe main city mitigation planning UHI, that is the status quo greenery and waterbodies basis. It is recommended to create "one ring, multi-wedge, multi-gallery,multi-point "—the multi-stage cooling system spatial layout planning. The planningfor the city center will be divided into high, medium and low. High solution is idealfor cooling the target scene, having a high cooling cost characteristics; in solution, theprinciple of the building not to change as much as possible to increase the water cooling effect is centered; low program, using a large amount of green area, withpart of the body of water for cooling, the cooling effect is poor.This dissertation presents five planning countermeasures to control UHI.①using third warning control UHI for plot rate, the corresponding volume ratio valueswere:1.0yellow, orange3.2, red4.15.②UHI enhancement of hardened groundcontrol can be divided into three warnings, the corresponding rates were hardenedground: yellow46%and59%orange,92%red.③water to cool the planning anddesign of reference: the average water rate increases10%UHI intensity decreased2.3℃;④to the surface from the average for each additional meter rise0.8℃, theaverage impact of water from375m, the best effective impact water distance200m;surface width cooling efficiency ladder of five control:70,145,310,670,1430m.⑤green plan for the reduction of UHI design reference: Average core green every10%increase in the rate of UHI intensity decreased0.18℃; UHI reduction of1.5℃greenrate required to achieve more than83%; UHI reduction of1-1.5℃, green rateshould reach56-83%, UHI reduction of0.5-1℃green rate should reach28-56%.The main innovation of this dissertation are the following:First, according to human body temperature thermal comfort and physiologicalresponses, based on the local average summer temperatures, this dissertationproposed the UHI intensity proposed classification and thermal comfort level of theaffected division method.UHI spatial distribution pattern studies to reduce the impactof the summer UHIs provide a space for people to adjust the reference standardzoning classification. Meanwhile, the classification method can be used with standardUHI green building echoes form a reference standard macroscopic UHI control.Second, this dissertation gave the concept of the algorithm proposed dual UHIintensity indicators—the highest UHI warming and UHI warming gross. Effectivesolution to the UHI intensity form measure brought problems, both expressedappreciation to bring the highest temperature UHI effect, but also indicates howmuch UHI measurement problems caused increased heat. To UHI studies and urbanplanning provides a quantifiable, refer to the layout parameters and mechanismanalysis. Third, this dissertation proposed the core plot rate, core building density, corehardface rate, the rate of the core surface and the concept of core green rate ofthinking. Clarified through further research, core green rate, scale sensitive corevolume ratio, core building density, core hardface rate, the rate of the core surface,and the intensity of the UHI effect of spatial and temporal characteristics of keyparameters such as layout, also proposed control plot rate of UHIs, hardened groundearly warning parameters. The concept of floor area ratio, building density, surfacehardening rate, green rate, is calculated in units of blocks, the whole plot is actuallyhomogenization, ignoring the differences in the spatial location of each point on. Theauthor proposed the concept of thinking is: the value of a point in space, is the pointof the core, the space within a certain distance of the results, which is more in linewith the actual situation.Fourth, this dissertation mentioned the development of the UHI simulationforecast and early warning information system. To achieve the UHI data management,UHI intensity simulations predict that the UHI univariate warning functions. Thesystem is not only able to conduct UHI intensity space simulation and prediction ofplot rate, hardened ground can be UHI warning. Systems implemented independentlydeveloped libraries: OPERBASE class, TXTOPER class.