139
7
Developing a Composite
Indicator with Landsat
Thematic Mapper/
Enhanced Thematic
Mapper Plus Images for
Drought Assessment in
a Coastal Urban Region
Zhiqiang Gao, Wei Gao, and Ni-Bin Chang
CONTENTS
7.1 Introduction .................................................................................................. 140
7.1.1 Motivation of Study .......................................................................... 140
7.1.2 Background of the Single Drought Index ......................................... 141
7.1.3 Need to Develop a Composite Drought Indicator ............................ 142
7.2 Materials and Methods ................................................................................. 143
7.2.1 Study Area ........................................................................................ 143
7.2.2 Image Processing of Multisensor Data ............................................ 143
7.2.3 Retrieval of LULC Patterns ............................................................. 146
7.2.4 Retrieval of Land Surface Heat Fluxes ............................................ 146
7.2.5 Retrieval of LST ............................................................................... 147
7.2.6 Calculations of NDVI, ANDVI, MSAVI, and SAVI ............................ 148
7.2.7 Calculations of RWSI ........................................................................ 148
7.2.8 Calculations of TVDI ........................................................................ 149
7.3 Results of Spatial Analysis for Drought Assessment ................................... 150
7.3.1 Spatial Patterns of LULC, VIs, and LST ......................................... 150
7.3.2 Building a Relationship between TVDI and RWSI for Drought
Impact Assessment ........................................................................... 154
7.4 Discussion of the Urban Heat Island Effect ................................................. 158
7.4.1 Urban Heat Island Effect .................................................................. 158
7.4.2 ANDVI Effect on LST and UHI ....................................................... 159
7
Developing a Composite
Indicator with Landsat
Thematic Mapper/
Enhanced Thematic
Mapper Plus Images for
Drought Assessment in
a Coastal Urban Region
Zhiqiang Gao, Wei Gao, and Ni-Bin Chang
CONTENTS
7.1 Introduction .................................................................................................. 140
7.1.1 Motivation of Study .......................................................................... 140
7.1.2 Background of the Single Drought Index ......................................... 141
7.1.3 Need to Develop a Composite Drought Indicator ............................ 142
7.2 Materials and Methods ................................................................................. 143
7.2.1 Study Area ........................................................................................ 143
7.2.2 Image Processing of Multisensor Data ............................................ 143
7.2.3 Retrieval of LULC Patterns ............................................................. 146
7.2.4 Retrieval of Land Surface Heat Fluxes ............................................ 146
7.2.5 Retrieval of LST ............................................................................... 147
7.2.6 Calculations of NDVI, ANDVI, MSAVI, and SAVI ............................ 148
7.2.7 Calculations of RWSI ........................................................................ 148
7.2.8 Calculations of TVDI ........................................................................ 149
7.3 Results of Spatial Analysis for Drought Assessment ................................... 150
7.3.1 Spatial Patterns of LULC, VIs, and LST ......................................... 150
7.3.2 Building a Relationship between TVDI and RWSI for Drought
Impact Assessment ........................................................................... 154
7.4 Discussion of the Urban Heat Island Effect ................................................. 158
7.4.1 Urban Heat Island Effect .................................................................. 158
7.4.2 ANDVI Effect on LST and UHI ....................................................... 159