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Title: A global map of urban extent from nightlights

Urbanization, one of the major human induced land-cover and land-use changes, has a profound impact on the Earth system including biodiversity, the cycling of water and carbon and exchange of energy and water between Earth’s surface and atmosphere, all affecting weather and climate. Accurate information on urban areas and their spatial distribution at the regional and global scales is important for scientific understanding of their contribution to the changing Earth system, and for practical management and policy decisions. We developed a method to map the urban extent from the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime stable-light data at the global level and derived a new global map of 1-km urban extent for year 2000. Based on this map, we found that globally, urban land area is about 0.5% of total land area but ranges widely at regional level from 0.1% in Oceania to 2.3% in Europe. At the country level, urban land area varies from lower than 0.01% to higher than 10%, but is lower than 1% for most (70%) countries. Urbanization follows land mass distribution, as anticipated, with the highest concentration found between 30°N to 45°N latitude and the largest longitudinal peak around 80°W. Based on amore » sensitivity analysis and comparison with other global urban area products, we found that our global product of urban area provides a reliable estimate of global urban areas and offer the potential of capturing more accurately their spatial and temporal dynamics.« less
Authors:
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Publication Date:
OSTI Identifier:
1182943
Report Number(s):
PNNL-SA-107842
Journal ID: ISSN 1748-9326; 400409900
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Environmental Research Letters
Additional Journal Information:
Journal Volume: 10; Journal Issue: 5; Journal ID: ISSN 1748-9326
Publisher:
IOP Publishing
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES nightlights, global, urban, threshold, DMSP/OLS