Vegetation Diagnosis Using Remote Sensing In Capital Regions Of China And Pakistan

Consequent to the critical process of rapid urbanization,the contemporary structure and function of cities have been changing,through expansion of urban periphery,modification of ecological diversity,and energy flows.Among proximate determinants,urban expansion primarily depends on socio-economic factors,migration from rural to urban areas,urban planning,and land use policies.Although,urbanization supports social-economic growth;however,the natural resources of cities are being converted into urban land through the process of land-use and land-cover change.The transformation of natural vegetation of cities into developed land is leading to serious eco-environmental problems,such as urban heat islands,air pollution,and biodiversity loss.Vegetation plays a vital role in urban regions from different prospects,i.e.,maintaining ecological balance,protecting biodiversity and alleviating thermal impacts to improve the quality of living conditions.The prime objective of this doctoral research is to study the implications of vegetation dynamics in urban environments,and to investigate the effectiveness of current landscape greening initiatives.For this purpose,three specific questions were addressed include 1)how the cooling effect of vegetation varies in local climate zones and impact the eco-environment conditions? 2)how green space structure and composition influence the urban thermal environments? 3)what is the effectiveness of ongoing landscape greening plans? This research was carried out in two Asian capitals: Beijing,China and Islamabad,Pakistan for cross learning purpose.While one at the lateral stage rapid expansion and development and other at the early stage of expansion and has possibility to learn from earlier experiments.Earth observation supported data has encouraged large-scale research on the urban vegetation and across the continents for both large-and small-sized cities of the world.The work primarily capitalized on Earth Observation data as proxy to in situ observation which also enable the inter-comparison among two cities.In this research,a high-resolution satellite imagery of Gaofen-1 and a medium resolution imagery of Landsat was utilized for land-use / land-cover mapping and Land Surface Temperature retrieval.Whereas,socio-economic,climatic,geophysical,and proximity variables were applied for land-use / land-cover simulation and local climate zones classification.The first study,evaluates and compare the eco-environmental conditions of both cities by investigating cooling effect of vegetation in urban environments.The results indicate that comparatively,a higher cooling effect of vegetation presence was observed in rural and suburban zones of Beijing as compared to Islamabad,while the urban zone of Islamabad was found cooler than Beijing's urban zone.The worst eco-environmental conditions were found in urban zones of both cities where the vegetation fraction is very low,meanwhile,this condition is more serious in Beijing.The second study,explored the methodological aspects on association between structure of green space characteristics and urban thermal conditions of both cities.The association of green space structure and composition with thermal environments indicate that both vegetation composition and configuration influence surface temperature distributions;however,vegetation composition appeared to have a slightly greater effect.The cooling effect can be produced more effectively by increasing green space percentage,planting trees in big patches with equal distribution,and avoiding complex-shaped green spaces.The green space cool islands principle indicates that surface temperature can be decreased by increasing the green space area,increasing the water bodies,or by decreasing the fraction of impervious surfaces.The third major study,explores the current landscape greening policies-based land-use / land-over scenarios to investigate the future effectiveness of ongoing greening plans.The greening plans developed for Beijing indicate that “landscape and greening policy” is the most effective plan in increasing the green land of Beijing city and it can possibly be applied on Islamabad after basic amendments according to the local conditions and available resources to slowdown the high rate of vegetation degradation.“Business-As-Usual” scenario predicts an overall expansion in Beijing's greenery,while Islamabad will encounter a decline in green resources.Under “Urban Green-space Work Plan” scenario,urban green spaces and other vegetation area of Beijing will expand with a decent rate,while for Islamabad,green land loss rate will slow down to some extent.Islamabad at this early growing stage,need to learn from Beijing's environmental crisis in past to improve the eco-environmental conditions by controlling the associated factors in the future.The vegetation degradation rate of Islamabad is found to be higher than Beijing and there is no greening policy for city's landscape to compensate this loss.Beijing has enacted many greening policies,and it is inferred from the results that vegetation degradation in Islamabad could be lessened by implementing “landscape and greening policy” of Beijing;after basic amendments according to the local conditions and available resources.The innovations of this research are listed below1.Normalized Mutual Information(NMI)coupled with remote sensing,has rarely been applied to explore the amount of information shared between the of two variables.2.Cooling effect of vegetation has never been compared based on Local Climate Zones of two cities,different in geographical locations,scales,vegetation coverage,environmental conditions and socio-economic activities.3.The landscape greening policies of a city has hardly been tested on any other city to explore their effectiveness for poorly managed urban region.