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Urban growth and its impact on urban heat sink and island formation in the desert city of Dubai Ahmed Khalaf Nassar M.Sc., B.Sc., A thesis submitted to Lancaster University in fulfilment of the requirements for the degree of Doctor of Philosophy September, 2015 UNIVERSITY LIBRARY 05 JUL 2016 LANCASTER Lancaster E 3 University * * ProQuest Number: 11003592 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 11003592 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Urban growth and its impact on urban heat sink and heat island formation in the desert city of Dubai Ahmed Khalaf Nassar A thesis submitted to Lancaster University in fulfilment of the requirements for the degree of Doctor of Philosophy Lancaster Environment Centre, Faculty of Science and Technology Lancaster University, United Kingdom September, 2015 Supervised by: Dr. G. Alan Blackburn and Dr. J. Duncan Whyatt Lancaster C3 University * * Urban growth and its impact on urban heat sink and island formation in the desert city of Dubai Ahmed Khalaf Nassar M.Sc., B.Sc. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy. September 2015 Abstract The rapid pace of urban growth in Dubai has attracted the attention of economists, environmentalists and urban planners. This thesis quantifies the extent of urbanisation within the Emirate since the discovery of oil and investigates the impacts of such growth on urban temperatures. The study used remotely-sensed imagery in the absence of publicly available data on city growth and microclimate. The study used a hybrid classification method and landscape metrics to capture historical urban forms, rates and engines of growth in the Emirate. Stepwise multiple regression analysis techniques were subsequently used to investigate the relationship between the rate and form of urbanisation and the intensity of the urban heat sink between 1990 and 2011. Local Climate Zones were then developed to specifically investigate the impacts of urban geometry variables and proximity to water on both urban heat sinks during the day-time and urban heat islands during the night. The study revealed a significant increase in urban area over time (1972-2011) with accelerated phases of growth, linked to local and global economic conditions, occurring during specific periods. Physical urban growth has now outpaced population growth, indicating urban sprawl. This growth has occurred at the expense of sand and has included a significant increase in vegetation and water bodies unlike other desert cities in the Gulf region. The results demonstrated that urban growth has promoted a heat sink effect during daytime and that all urban land use types contributed to this effect. Urban albedo was not responsible for the daytime urban heat sink; other factors including the specific heat capacity of urban materials, urban geometry and proximity to the Gulf were mainly responsible. Furthermore, increases in vegetation cover and impervious surface cover over time have contributed to the daytime (morning) urban heat sink. At night-time, urban geometry and proximity to the Gulf were the major influences upon the formation of urban heat islands. This research contributes to better understanding of urbanisation in desert cities as demonstrated through Dubai, revealing previously unknown spatiotemporal variations in urban areas across the city through the use of a time-series of satellite images. The findings provide new insights into the impacts of land cover, land use, proximity to water and urban geometry on the formation of urban heat sinks and urban heat islands in the desert environment. Table of Contents List of abbreviations...................................................................................................................... x Acknowledgement........................................................................................................................ xi Declaration................................................................................................................................... xii Chapter 1 Introduction...............................................................................................................13 1.1 Rationale ................................................................................................................................ 13 1.2 Study area...............................................................................................................................15 1.2.1 Location and siz e .................................................................................................. 15 1.2.2 Physical properties and climate ......................................................................... 16 1.2.3 Socio-economic properties ..................................................................................17 1.3 Aim and objectives .............................................................................................................. 18 1.3.1 O bjectives................................................................................................................18 1.4 Thesis structure..................................................................................................................... 19 Chapter 2 Remote sensing in urban growth studies............................................................ 22 2.1 B ackground ...........................................................................................................................22 2.2 Location and extent of urban growth studies.................................................................23 2.3 Time span of urban growth studies ................................................................................. 24 2.4 Data used in urban growth studies ....................................................................................25 2.5 Data preparation and methods ...........................................................................................31 2.6 Classification Systems (schema) in urban growth studies ..........................................33 2.7 Image classification methods and accuracy assessment ............................................. 34 2.8 Spatial metrics used in urban studies ...............................................................................40 2.9 Urban studies in sandy desert cities ................................................................................. 42 2.10 Causes and implications of urban growth ....................................................................45 2.11 Conclusions .........................................................................................................................47 2.12 Summary............................................................................................................................. 49 Chapter 3 Urban heat islands....................................................................................................50 3.1 Background ...........................................................................................................................50 3.2 Urban heat island (UHI)......................................................................................................51 3.3 Factors affecting UHI intensity ........................................................................................ 54 3.3.1 Reduced vegetation in urban environment ......................................................54 3.3.2 Urban thermal properties .....................................................................................56 3.3.3 Low solar reflectivity ...........................................................................................57 3.3.4 Urban Geometry ................................................................................................... 58 3.3.5 Other factors .......................................................................................................... 60 3.4 UHI in sandy desert environment .....................................................................................60 3.5 Satellite thermal data used in urban thermal studies ................................................... 62 3.6 Satellite thermal Infrared (TIR) remote sensing ...........................................................66 3.7 UHI intensity mitigation .................................................................................................... 70 3.8 Conclusions ...........................................................................................................................72 3.9 Summary ................................................................................................................................73 Chapter 4 Developing the desert: The pace and process of urban growth in Dubai 74 Context ...........................................................................................................................................76 4.1. Introduction ..........................................................................................................................77