Satellite Monitoring of Urbanization in Megacities

Transcription

1 Satellite Monitoring of Urbanization in Megacities Yifang Ban Professor of Geoinformatics Department of Urban Planning & Environment KTH Royal Institute of Technology Stockholm, Sweden

2 Introduction In 2007, more than 50% of the world population live in cities Urbanization causes formation of megacities, population: > 10 million. 27 Megacities globally

3 Introduction World Urban Population 2025 Source: United Nations: World Urbanization Prospects, the 2011 Revision. New York 2012

4 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.

5 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

6 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:

7 Environmental Consequences Internal wind climate Long streets generate jet effects with high speed winds Skyscrapers act as magnets for lightning Source: pittsburghskyline.com

8 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

9 Study Areas LONDON MOSCOW LOS ANGELES NEW YORK BEIJING TOKYO MEXICO CITY DEHLI DHAKA SAN PAULO

10 Study Areas

11 Study Areas Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012)

12 Data Description Name Country Population Sattelite Sattelite (2011) imagery (old) imagery (new) Beijing China Delhi India Dhaka Bangladesh LA USA London UK 12, Mexico City Mexico Moscow Russia NYC USA Sao Paulo Brazil Shanghai China Tokyo Japan

13 Data Description Landsat MSS, TM and ETM images from 1970s to 2010 HJ-1B images from 2010

14 ESA Data ENVISAT ASAR archives ERS-1/2 archives

15 TPM Data TerraSAR-X/TanDEM-X data RADARSAR-2 Polarimetric SAR data

16 Methodology: Data Fusion FUSION SAR ENVISAT ASAR OPTICAL HJ-1B 16

17 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

18 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, 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.

19 Methodology: Image Classification Niu, X., and Y. Ban 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 Multitemporal RADARSAT-2 Ultra-Fine-Beam SAR Data for Urban Land Cover Classification. Canadian Journal of Remote Sensing, 38(01): 1-11, /m

20 Methodology: Change Detection Ban, Y. and O. A. Yousif, 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): Yousif, O. and Y. Ban, Improving Urban Change Detection from Multitemporal SAR Images Using PCA- NLM. IEEE Transaction on GeoScience and Remote Sensing.

21 Environmental Impact Assessment Maria Bobrinskaya, Remote Sensing for Analysis of Relationships between Land Cover and Land Surface Temperature in Ten Megacities. MSc thesis, Supervised by YifangBan, KTH Geoinformaitcs.

22 Environmental Impact Assessment Furberg, D. and Y. Ban, Satellite Monitoring of Urban Sprawl and Assessment of its Potential Environmental Impact in the GTA between 1985 and Environmental Management. Furberg, D. and Y. Ban, 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 Remote Sensing of Bidecadal Urbanization and Its Impact on Ecosystem Service in the Yangtze River Delta, Proceedings, Dragon 2 Final Symposium.

23 Results & Discussion

24 Results & Discussion Shanghai Zhang, Q.,Ban, Y., Hu, Y.; Liu, J The Trajectories of Urban Land and Industrial Land in Shanghai over the Past 30 Years. Joint Urban Remote Sensing Event, , Shanghai. London London Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012)

25 Results & Discussion Source: Taubenböck et al.,, Monitoring urbanization in mega cities from space. Remote Sensing of Environment 117 (2012)

26 LULC & LST HD built-up LD built-up Bare soil Agriculture Water Forest Beijing Change rate Area (sq.km) Area (sq.km) Urban High % Urban Low % Agriculture % Bare % Forest % Water %

27 1999 Beijing

28 Moscow 2010

29 Urbanization In China In China, urban areas increased from km2 in 1990s, to km2 in 2010s. Wang L et al, China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.

30 Urbanization In China Wang L et al, China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.

31 Urbanization on Air Temperature Shao, Q., C. Sun, J. Liu, Y. Ban, J. He and W. Kuang Impact of Urban Expansion on Meteorological Observation Data and Over-estimation to Regional Air Temperature in China. Acta Geographica Sinica (In Chinese).

32 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, China s urban expansion from 1990 to 2010 determined with satellite remote sensing. Chinese Bulletin of Sciences.

33 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

34 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