Investigating the Influence of Tropical Urban Climates on Vegetation Phenology

Investigating the Influence of Tropical Urban Climates on Vegetation Phenology A thesis submitted to The University of Manchester for the degree of Doctor of Philosophy in the Faculty of Humanities 2019 Peter Kabano School of Environment Education and Development ‘Blank page’ 2 Contents LIST OF TABLES .............................................................................................................................. 8 LIST OF FIGURES .......................................................................................................................... 10 LIST OF FIGURES IN APPENDIX .................................................................................................... 12 ABSTRACT .................................................................................................................................... 15 DECLARATION ............................................................................................................................. 17 COPYRIGHT STATEMENT ............................................................................................................. 18 ACKNOWLEDGEMENTS ............................................................................................................... 19 GLOSSARY OF ABBREVIATIONS ................................................................................................... 20 CHAPTER 1. RESEARCH IN CONTEXT ....................................................................................... 22 1.1 Landcover change and climate feedback .................................................................... 22 1.1.1 Urbanisation and urban climate ......................................................................... 23 1.2 Factors influencing tropical urban climate ................................................................. 25 1.2.1 Morphology of cities ........................................................................................... 25 1.2.2 Importance of vegetation in Tropical African cities ............................................ 25 1.2.3 Importance of water availability in tropical urban climate ................................ 25 1.3 Vegetation phenology in tropical urban environments .............................................. 26 1.3.1 Deciduous nature of trees in tropical cities ........................................................ 27 1.3.2 Landscape phenology in tropical cities ............................................................... 28 1.4 Thesis Aims and Contributions.................................................................................... 28 1.5 Research methodology ............................................................................................... 30 1.6 Thesis structure ........................................................................................................... 31 CHAPTER 2. LITERATURE REVIEW ........................................................................................... 33 2.1 Urban climate .............................................................................................................. 33 2.1.1 The Urban Heat Island (UHI) effect ..................................................................... 33 2.1.2 Quantifying UHI ................................................................................................... 37 2.1.3 Factors affecting Urban Heat islands .................................................................. 43 3 2.1.4 Urban Heat Islands in the tropics ........................................................................ 47 2.1.5 Urban dryness Island effect ................................................................................. 57 2.2 Vegetation Phenology ................................................................................................. 60 2.2.1 Quantifying vegetation phenology ...................................................................... 61 2.2.2 Remote sensing phenology ................................................................................. 62 2.2.3 Drivers of vegetation phenology ......................................................................... 65 2.3 Phenology in urban environments .............................................................................. 68 2.3.1 Phenology in tropical urban environments ......................................................... 69 2.3.2 Conclusion ........................................................................................................... 71 CHAPTER 3. METHODOLOGY ................................................................................................... 74 3.1 Study area .................................................................................................................... 74 3.1.1 Criteria for Choice of study area .......................................................................... 74 3.1.2 Description of study area .................................................................................... 75 3.2 Local scale climate and landscape phenological processes ........................................ 78 3.2.1 Urban form characterisation ............................................................................... 78 3.2.2 Landscape phenology characterisation ............................................................... 86 3.2.3 Land surface temperature ................................................................................... 90 3.3 Phenological processes of individual tree species ...................................................... 90 3.3.1 Select tree species ............................................................................................... 91 3.3.2 Phenology sampling sites .................................................................................... 92 3.3.3 Characterisation of surface cover and structure at each site ............................. 94 3.3.4 Phenology data collection ................................................................................... 95 3.3.5 Urban climate characterisation ........................................................................... 96 3.4 Data Processing and Analysis ...................................................................................... 98 3.4.1 Local scale climate and phenological processes .................................................. 98 3.4.2 Micro scale climate and phenological processes .............................................. 102 3.4.3 Analysis .............................................................................................................. 105 4 CHAPTER 4. EVIDENCE OF URBAN HEAT ISLAND IMPACTS ON LANDSCAPE PHENOLOGY IN A TROPICAL CITY 107 4.1 Abstract ..................................................................................................................... 107 4.2 Introduction .............................................................................................................. 108 4.3 Materials and methods ............................................................................................. 111 4.3.1 Study area ......................................................................................................... 111 4.3.2 Data ................................................................................................................... 112 4.3.3 Data analysis ..................................................................................................... 117 4.4 Results ....................................................................................................................... 118 4.4.1 Surface and structural differences between urban form (LCZ) types ............... 118 4.4.2 Phenology ......................................................................................................... 119 4.4.3 Land surface temperature ................................................................................ 120 4.4.4 Relationship between LST and Phenology ........................................................ 120 4.5 Discussion .................................................................................................................. 123 4.6 Conclusion ................................................................................................................. 125 CHAPTER 5. SPATIOTEMPORAL DYNAMICS OF URBAN CLIMATE DURING THE WET-DRY SEASON TRANSITION IN A TROPICAL AFRICAN CITY ................................................................. 127 5.1 Abstract ..................................................................................................................... 127 5.2 Introduction .............................................................................................................. 128 5.3 Methods .................................................................................................................... 131 5.3.1 Study area ......................................................................................................... 131 5.3.2 Data analysis ..................................................................................................... 135 5.4 Results ....................................................................................................................... 137 5.4.1 Temporal change in urban climate with relation to proportion of man-made surface 137 5.4.2 Influence of land cover on urban climate ......................................................... 140 5.5 Discussion .................................................................................................................

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