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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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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0303-2434 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 224
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Author Nordhaus, W.; Chen, X.
Title A sharper image? Estimates of the precision of nighttime lights as a proxy for economic statistics Type Journal Article
Year 2014 Publication Journal of Economic Geography Abbreviated Journal J of Econ Geog
Volume 15 Issue 1 Pages 217-246
Keywords Nighttime lights; luminosity; output measurement; national accounts; proxy measures; social science; economics; remote sensing
Abstract Much aggregate social-science analysis relies upon the standard national income and product accounts as a source of economic data. These are recognized to be defective in many poor countries, and are missing at the regional level for large parts of the world. Using updated luminosity (or nighttime lights) data, the present study examines whether such data contain useful information for estimating national and regional incomes and output. The bootstrap method is used for estimating the statistical precision of the estimates of the contribution of the lights proxy. We conclude that there may be substantial cross-sectional information in lights data for countries with low-quality statistical systems. However, lights data provide very little additional information for countries with high-quality data wherever standard data are available. The largest statistical concerns arise from uncertainties about the precision of standard national accounts data.
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Publisher Oxford University Press Place of Publication Editor
Language English Summary Language Original Title
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Notes Approved no
Call Number IDA @ john @ Serial 363
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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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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1878-0296 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 227
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Author Huang, B.J.; Wu, M.S.; Hsu, P.C.; Chen, J.W.; Chen, K.Y.
Title Development of high-performance solar LED lighting system Type Journal Article
Year 2010 Publication Energy Conversion and Management Abbreviated Journal Energy Conversion and Management
Volume 51 Issue 8 Pages 1669-1675
Keywords Stand-alone solar system; Off-grid solar system; Solar-powered lighting; LED lighting; Solar LED lighting; LED; outdoor lighting
Abstract The present study developed a high-performance charge/discharge controller for stand-alone solar LED lighting system by incorporating an nMPPO system design, a PWM battery charge control, and a PWM battery discharge control to directly drive the LED. The MPPT controller can then be removed from the stand-alone solar system and the charged capacity of the battery increases 9.7%. For LED driven by PWM current directly from battery, a reliability test for the light decay of LED lamps was performed continuously for 13,200 h. It has shown that the light decay of PWM-driven LED is the same as that of constant-current driven LED. The switching energy loss of the MOSFET in the PWM battery discharge control is less than 1%. Three solar-powered LED lighting systems (18 W, 100 W and 150 W LED) were designed and built. The long-term outdoor field test results have shown that the system performance is satisfactory with the control system developed in the present study. The loss of load probability for the 18 W solar LED system is 14.1% in winter and zero in summer. For the 100 W solar LED system, the loss of load probability is 3.6% in spring.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0196-8904 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 330
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Author Townsend, A.C.; Bruce, D.A.
Title The use of night-time lights satellite imagery as a measure of Australia's regional electricity consumption and population distribution Type Journal Article
Year 2010 Publication International Journal of Remote Sensing Abbreviated Journal International Journal of Remote Sensing
Volume 31 Issue 16 Pages 4459-4480
Keywords DMSP-OLS; light at night; remote sensing; satellite; skyglow
Abstract Satellite imagery of night-time lights provided by the US Air Force Defense Meteorological Satellite Program (DMSP), using the Operational Linescan System (OLS), has been used to estimate the spatial distribution of electricity consumption throughout Australia. For the period 1997 to 2002, there was very high correlation between state electricity consumption and night-time lights with an R 2 value of 0.9346 at the state and territory spatial resolution. To increase the accuracy at which electricity consumption can be estimated at greater spatial resolution, an Overglow Removal Model (ORM) was developed to overcome the overglow effect caused by the dispersion of light into surrounding areas. The ORM makes use of the relationship between light source strength and the overglow/dispersion distance from the light source. As electricity consumption statistics at a greater spatial resolution than the state or territory level are not publically available in Australia, population statistics at the statistical local area (SLA) were used to demonstrate the increased accuracy of the ORM at returning the overglow light to its source, and, in turn, the accuracy of measuring electricity consumption. The ORM enabled an estimation of the electricity consumption of SLAs, greater than 10 km2, with an R 2 value of 0.8732, which is a 25.4% increase in accuracy over untreated data before applying the ORM. The increase in accuracy of the location of the origin of night-time lights can enable better georeferencing of satellite imagery of night-time lights and greater accuracy in locating population centres and centres of economic development, and assist with electricity infrastructure planning in regions of the world where statistics are not readily available. The result of the ORM is a map of Australian electricity consumption, and an estimation of the regional electricity consumption for all SLAs greater than 10 km2 in size is included.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0143-1161 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 230
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