Satellite Monitoring of Urbanization in Megacities Yifang Ban Professor of Geoinformatics Department of Urban Planning & Environment KTH Royal Institute of Technology Stockholm, Sweden
Introduction In 2007, more than 50% of the world population live in cities Urbanization causes formation of megacities, population: > 10 million. 27 Megacities globally
Introduction World Urban Population 2025 Source: United Nations: World Urbanization Prospects, the 2011 Revision. New York 2012
Environmental Consequences Urban heat island (UHI) and heat waves UHI urban air temperatures higher than surrounding rural areas. The average air temperature in a city with 1 million inhabitants is 1-3 degrees warmer. Heat waves: In the afternoon, the difference can be 12 degrees warmer, no night time cooling. Death rate raise during heat waves.
Environmental Consequences High concentrations of aerosols, exhaust gases, pollution and dust Hazardous to health Increased smog, haze, fog, clouds Source: The Associated Press Source: Suicup via Wikimedia
Environmental Consequences Paved surfaces -> rainfall water -> flooding Water runs on the paved surface. Poor storm water systems, unable to prevent flooding from rains 79 people died in July 2012 Beijing flooding Source: rendezvous.blogs.nytimes.com Source: BBC News Source: www.theatlanticcities.com
Environmental Consequences Internal wind climate Long streets generate jet effects with high speed winds Skyscrapers act as magnets for lightning Source: pittsburghskyline.com
Research Objectives To map and monitor urbanization in Megacities To develop effective classification and change detection methods To assess the environmental impact of urbanization Land Cover & Land Surface Temprature Landscape fragmentation Ecosystem Services
Study Areas LONDON MOSCOW LOS ANGELES NEW YORK BEIJING TOKYO MEXICO CITY DEHLI DHAKA SAN PAULO
Study Areas
Study Areas Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012) 162 176
Data Description Name Country Population Sattelite Sattelite (2011) imagery (old) imagery (new) Beijing China 16.4 1999-10-21 2009-09-22 Delhi India 23.0 2000-02-19 2010-02-14 Dhaka Bangladesh 14.0 1999-11-24 2009-11-27 LA USA 17.6 2000-09-15 2010-09-19 London UK 12,6 2002-09-13 2011-09-30 Mexico City Mexico 23.2 2000-02-02 2010-02-05 Moscow Russia 16.2 2001-05-04 2010-06-22 NYC USA 21.5 2000-10-20 2010-10-08 Sao Paulo Brazil 21.1 2000-10-20 2010-10-08 Shanghai China 25.3 2000 2010 Tokyo Japan 34.5 2002-03-19 2011-04-05
Data Description Landsat MSS, TM and ETM images from 1970s to 2010 HJ-1B images from 2010
ESA Data ENVISAT ASAR archives ERS-1/2 archives
TPM Data TerraSAR-X/TanDEM-X data RADARSAR-2 Polarimetric SAR data
Methodology: Data Fusion FUSION SAR ENVISAT ASAR OPTICAL HJ-1B 16
Methodology: KTH-SEG Preprocessing Segmentation Optical data Coregistration Parameter selection Growing off edges Mutual merging Threshold merging SAR data Speckle filtering Edge detection Growing on edges Min size merging Classification Sample selection - > SVM - Training Land cover/use map Quality Assesment SVM- Prediction
Methodology: KTH-SEG (a) Grow off edges (b) Grow on edges (c) Mutual merging (d) Threshold merging (e) Min size merging Ban, Y. and A. Jacob, 2013. Object-based Fusion of Multitemporal Multi-angle ENVISAT ASAR and HJ-1 Multispectral Data for Urban Land-Cover Mapping. IEEE Transaction on GeoScience and Remote Sensing.
Methodology: Image Classification Niu, X., and Y. Ban. 2013. Multitemporal RADARSAT-2 Polarimetric SAR Data for Urban Land Cover Classification using Object-based Support Vector Machine and Rule-based Approach, International Journal of Remote Sensing, 34(1):1-26. Niu X. and Y. Ban, 2013, Multitemporal Polarimetric RADARSAT-2 SAR Data for Urban Land Cover Mapping Through a Dictionary-based and a Rule-based Model Selection in a Contextual SEM Algorithm. Canadian Journal of Remote Sensing. Hu, H. and Y. Ban. 2012. Multitemporal RADARSAT-2 Ultra-Fine-Beam SAR Data for Urban Land Cover Classification. Canadian Journal of Remote Sensing, 38(01): 1-11, 10.5589/m12-008.
Methodology: Change Detection Ban, Y. and O. A. Yousif, 2012. Multitemporal Spaceborne SAR Data for Urban Change Detection in China. IEEE Journal on of Selected Topics in Applied Earth Observations and Remote Sensing, 5(4): 1087-1094. Yousif, O. and Y. Ban, 2013. Improving Urban Change Detection from Multitemporal SAR Images Using PCA- NLM. IEEE Transaction on GeoScience and Remote Sensing.
Environmental Impact Assessment Maria Bobrinskaya, 2012. Remote Sensing for Analysis of Relationships between Land Cover and Land Surface Temperature in Ten Megacities. MSc thesis, Supervised by YifangBan, KTH Geoinformaitcs.
Environmental Impact Assessment Furberg, D. and Y. Ban, 2012. Satellite Monitoring of Urban Sprawl and Assessment of its Potential Environmental Impact in the GTA between 1985 and 2005. Environmental Management. Furberg, D. and Y. Ban, 2012. Satellite Monitoring of Urban Land Cover Change in Stockholm between 1986 and 2006 and Environmental Impact Assessment through the Use of Indicators. Earth Observation for Global Change 2011, Springer Book. Haas, J. and Y. Ban. 2012. Remote Sensing of Bidecadal Urbanization and Its Impact on Ecosystem Service in the Yangtze River Delta, Proceedings, Dragon 2 Final Symposium.
Results & Discussion
Results & Discussion Shanghai Zhang, Q.,Ban, Y., Hu, Y.; Liu, J. 2009. The Trajectories of Urban Land and Industrial Land in Shanghai over the Past 30 Years. Joint Urban Remote Sensing Event, 1022-1028, Shanghai. London London Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012) 162 176
Results & Discussion Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012) 162 176
1999 2009 LULC & LST HD built-up LD built-up Bare soil Agriculture Water Forest Beijing 1999 2010 Change rate Area (sq.km) Area (sq.km) Urban High 348.7086 685.4760 97% Urban Low 975.2940 1552.0374 59% Agriculture 1239.0210 568.2888-54% Bare 679.7268 149.6529-78% Forest 336.8700 660.6441 96% Water 56.3796 19.9008-65%
1999 Beijing
Moscow 2010
Urbanization In China In China, urban areas increased from 12252.9 km2 in 1990s, to 40533.8 km2 in 2010s. Wang L et al, 2012. China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.
Urbanization In China Wang L et al, 2012. China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.
Urbanization on Air Temperature Shao, Q., C. Sun, J. Liu, Y. Ban, J. He and W. Kuang. 2009. Impact of Urban Expansion on Meteorological Observation Data and Over-estimation to Regional Air Temperature in China. Acta Geographica Sinica (In Chinese).
Future Research GEO Global urban mapping and monitoring Very high resolution SAR &/or optical data fusion for urban analysis Novel methods for urban land cover mapping & change detection Quantitative representation of LULC-LST relationship Converting LULC change to pressure on biodiversity Wang L et al, 2012. China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.
Acknowledgement This research is part of the Urbanization and Climate Project within the ESA-MOST Dragon 3 Program. Prof. Yifang Ban, KTH Royal Institute of Technology, Geoinformatics, European Lead PI Prof. Peng Gong, Tsinghua University & University of California, Berkeley, Chinese Lead PI Prof. Paolo Gamba, University of Pavia, Department of Electronics, Remote Sensing Group Prof. Peijun Du, Nanjing University, China Dr. Hannes Taubenböck, DLR Earth Observation Center German Remote Sensing Data Center Prof. Jing Li, Beijing Normal University
Acknowledgement This research is funded through research grants from the Swedish National Space Board, Formas and VR. Contributing researchers from KTH: Maria Bobrinskaya, MSc student Dr. Juan Deng, Visiting researcher Dorothy Furberg, PhD student Jan Haas, PhD student Hongtao Hu, PhD student Alexander Jacob, PhD student Dr. Xin Niu, Postdoctoral researcher Osama Yousif, PhD student