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Author Zhao, N.; Samson, E.L.
Title Estimation of virtual water contained in international trade products using nighttime imagery Type Journal Article
Year 2012 Publication International Journal of Applied Earth Observation and Geoinformation Abbreviated Journal International Journal of Applied Earth Observation and Geoinformation
Volume 18 Issue Pages 243-250
Keywords Virtual water; Nighttime imagery; Lit area; Urban population; International trade product; DMSP-OLS; remote sensing; satellite; light at night
Abstract Freshwater that is consumed in the process of producing a commodity is called virtual water – it represents all water use contained in that commodity. In social systems, water resources can flow when commodities are traded from one region to another. Quantitative monitoring and assessing virtual water flow related to international trade products is an important issue to comprehensively understand the balance of global water resources. In this study we tested the potential of the Defense Meteorological Satellite Program's Operational Linescan System (DMSP-OLS) nighttime images in conjunction with the LandScan population dataset for estimation of virtual water contained in international trade products. Lit area (areal extent of night lights) and urban population were selected as proxies to estimate export virtual water (EVW), import virtual water (IVW), and traded virtual water (TVW) (summed EVW and IVW), respectively, on the national level. The results showed that IVW can be more accurately estimated than EVW regardless of lit area or urban population. Lit area is normally more appropriate for estimation of the virtual water of developed countries than those of developing countries, but urban population is more appropriate for estimation of the virtual water of developing countries than those of developed countries. Urban population is a better proxy than total population for estimations of virtual water. This study makes a negative finding in that there are relatively large underestimations for developed countries. Another negative finding is that neither lit area nor urban population can be used to estimate net import virtual water (NIVW).
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ISSN 0303-2434 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number IDA @ john @ Serial 224
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Author Roy Chowdhury, P.K.; Maithani, S.; Dadhwal, V.K.
Title Estimation of urban population in Indo-Gangetic Plains using night-time OLS data Type Journal Article
Year 2012 Publication International Journal of Remote Sensing Abbreviated Journal International Journal of Remote Sensing
Volume 33 Issue 8 Pages 2498-2515
Keywords DMSP-OLS; satellite; remote sensing; Indo-Gangetic Plains; Urban Population; Urban environment
Abstract In this study the applicability of a night-time Operational Linescan System (OLS) sensor in urban population estimation has been examined. The study area consisted of the Indian portion of the Indo-Gangetic Plains. Using night-time OLS data, urban areas situated in the study area were mapped and their areal extent was determined. A linear relationship between the natural log of the urban area and the natural log of the corresponding population was established. The model was calibrated for the year 2001 and then validated for the year 1995. Subsequently, the model was modified using ancillary factors such as electricity consumption to reduce the error in population estimation. Thus, this study attempted to explore the applicability of nighttime OLS data in urban population estimation.
Address Indian Institute of Remote Sensing , Dehradun, 248 001, India
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ISSN 0143-1161 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number IDA @ john @ Serial 226
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Author Small, C.; Elvidge, C.D.
Title Mapping Decadal Change in Anthropogenic Night Light Type Journal Article
Year 2011 Publication Procedia Environmental Sciences Abbreviated Journal Procedia Environmental Sciences
Volume 7 Issue Pages 353-358
Keywords night light; urban; development; EOF analysis; PCA; Zipf; spatial network; fractal; percolation; DMSP-OLS; remote sensing; satellite; light at night
Abstract The Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) sensors have imaged emitted light from Earth's surface since the 1970's. Temporal overlap in the missions of 5 OLS sensors allows for intercalibration of the annual composites over the past 19 years [1]. The resulting image time series captures a spatiotemporal signature of human settlement growth and evolution. We use temporal Empirical Orthogonal Function (EOF) analysis to characterize and quantify patterns of temporal change in stable night light brightness and spatial extent since 1992. Temporal EOF analysis provides a statistical basis for representing spatially abundant temporal patterns in the image time series as uncorrelated vectors of brightness as a function of time from 1992 to 2009. The variance partition of the eigenvalue spectrum combined with temporal structure of the EOFs provides a basis for distinguishing between deterministic temporal trends and stochastic year to year variance. The low order EOFs and Principal Components (PC) space together discriminate both earlier (1990s) and later (2000s) increases and decreases in brightness. Inverse transformation of these low order dimensions reduces stochastic variance sufficiently so that tri-temporal composites depict deterministic decadal trends. The most pronounced changes occur in Asia. Throughout Asia a variety of different patterns of brightness increase are visible in tri-temporal brightness composites – as well as some conspicuous areas of apparently decreasing background luminance and, in many places, intermittent light suggesting development of infrastructure rather than persistently lighted development. Vicarious validation using higher resolution imagery reveals multiple phases of urban growth in several cities, numerous instances of highway construction, extensive terracing networks and hydroelectric dam construction [3]. Lights also allow us to quantify the size distribution and connectedness of different intensities of development. Over a wide range of brightnesses, size distributions of spatially contiguous lighted area are well-fit by power laws with exponents near -1 as predicted by Zipf's Law. However, the larger lighted segments are much larger than individual cities; they correspond to vast spatial networks of contiguous development.
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ISSN 1878-0296 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number IDA @ john @ Serial 227
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Author Sutton, P.C.
Title A scale-adjusted measure of “Urban sprawl” using nighttime satellite imagery Type Journal Article
Year 2003 Publication Remote Sensing of Environment Abbreviated Journal Remote Sensing of Environment
Volume 86 Issue 3 Pages 353-369
Keywords Urban sprawl; Sprawl Line; Nighttime satellite imagery; DMSP-OLS; remote sensing; satellite; llight at night
Abstract “Urban Sprawl” is a growing concern of citizens, environmental organizations, and governments. Negative impacts often attributed to urban sprawl are traffic congestion, loss of open space, and increased pollutant runoff into natural waterways. Definitions of “Urban Sprawl” range from local patterns of land use and development to aggregate measures of per capita land consumption for given contiguous urban areas (UA). This research creates a measure of per capita land use consumption as an aggregate index for the spatially contiguous urban areas of the conterminous United States with population of 50,000 or greater. Nighttime satellite imagery obtained by the Defense Meteorological Satellite Program's Operational Linescan System (DMSP OLS) is used as a proxy measure of urban extent. The corresponding population of these urban areas is derived from a grid of the block group level data from the 1990 U.S. Census. These numbers are used to develop a regression equation between Ln(Urban Area) and Ln(Urban Population). The ‘scale-adjustment’ mentioned in the title characterizes the “Urban Sprawl” of each of the urban areas by how far above or below they are on the “Sprawl Line” determined by this regression. This “Sprawl Line” allows for a more fair comparison of “Urban Sprawl” between larger and smaller metropolitan areas because a simple measure of per capita land consumption or population density does not account for the natural increase in aggregate population density that occurs as cities grow in population. Cities that have more “Urban Sprawl” by this measure tended to be inland and Midwestern cities such as Minneapolis–St. Paul, Atlanta, Dallas–Ft. Worth, St. Louis, and Kansas City. Surprisingly, west coast cities including Los Angeles had some of the lowest levels of “Urban Sprawl” by this measure. There were many low light levels seen in the nighttime imagery around these major urban areas that were not included in either of the two definitions of urban extent used in this study. These areas may represent a growing commuter-shed of urban workers who do not live in the urban core but nonetheless contribute to many of the impacts typically attributed to “Urban Sprawl”. “Urban Sprawl” is difficult to define precisely partly because public perception of sprawl is likely derived from local land use planning decisions, spatio-demographic change in growing urban areas, and changing values and social mores resulting from differential rates of international migration to the urban areas of the United States. Nonetheless, the aggregate measures derived here are somewhat different than similar previously used measures in that they are ‘scale-adjusted’; also, the spatial patterns of “Urban Sprawl” shown here shed some insight and raise interesting questions about how the dynamics of “Urban Sprawl” are changing.
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ISSN 0034-4257 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number IDA @ john @ Serial 233
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Author Johansson, M.; Pedersen, E.; Maleetipwan-Mattsson, P.; Kuhn, L.; Laike, T.
Title Perceived outdoor lighting quality (POLQ): A lighting assessment tool Type Journal Article
Year 2013 Publication Journal of Environmental Psychology Abbreviated Journal Journal of Environmental Psychology
Volume 39 Issue Pages 14-21
Keywords Perception; Street lighting; Observation-based environmental assessment; Urban space
Abstract A shift towards more energy-efficient light sources for outdoor lighting such as light-emitting diodes (LEDs) is underway. Photometric measures are not sufficient to capture how users experience the light, so complementary tools are required. This study aimed to develop an observer-based environmental assessment tool, based on bipolar semantic differentials, for outdoor lighting in urban spaces. Exploratory (N = 130) and confirmatory (N = 117) factor analyses of observations of lighting installations made by laypersons on-site along pedestrian paths, resulted in two dimensions of high reliability: the Perceived Strength Quality (PSQ, Cronbach's alpha = 0.82–0.85) and the Perceived Comfort Quality (PCQ, Cronbach's alpha = 0.77–0.81). PSQ and PCQ differentiated between light sources of different illuminance level, colour temperature and colour rendering. Regression analyses showed that the perceived lighting qualities helped to explain the variance in visual accessibility, whereas PCQ helped to explain perceived danger in the environment. The perceived lighting qualities can add to the understanding of pedestrians' perception of outdoor lighting, and is proposed as a complementary tool for development of sustainable light designs in the urban environment.
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ISSN 0272-4944 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number IDA @ john @ Serial 279
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