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Author Zhang, G.; Li, L.; Jiang, Y.; Shen, X.; Li, D. url  doi
openurl 
  Title On-Orbit Relative Radiometric Calibration of the Night-Time Sensor of the LuoJia1-01 Satellite Type Journal Article
  Year 2018 Publication Sensors (Basel, Switzerland) Abbreviated Journal (down) Sensors (Basel)  
  Volume 18 Issue 12 Pages  
  Keywords Instrumentation; Remote Sensing  
  Abstract The LuoJia1-01 satellite can acquire high-resolution, high-sensitivity nighttime light data for night remote sensing applications. LuoJia1-01 is equipped with a 4-megapixel CMOS sensor composed of 2048 x 2048 unique detectors that record weak nighttime light on Earth. Owing to minute variations in manufacturing and temporal degradation, each detector's behavior varies when exposed to uniform radiance, resulting in noticeable detector-level errors in the acquired imagery. Radiometric calibration helps to eliminate these detector-level errors. For the nighttime sensor of LuoJia1-01, it is difficult to directly use the nighttime light data to calibrate the detector-level errors, because at night there is no large-area uniform light source. This paper reports an on-orbit radiometric calibration method that uses daytime data to estimate the relative calibration coefficients for each detector in the LuoJia1-01 nighttime sensor, and uses the calibrated data to correct nighttime data. The image sensor has a high dynamic range (HDR) mode, which is optimized for day/night imaging applications. An HDR image can be constructed using low- and high-gain HDR images captured in HDR mode. Hence, a day-to-night radiometric reference transfer model, which uses daytime uniform calibration to calibrate the detector non-uniformity of the nighttime sensor, is herein built for LuoJia1-01. Owing to the lack of calibration equipment on-board LuoJia1-01, the dark current of the nighttime sensor is calibrated by collecting no-light desert images at new moon. The results show that in HDR mode (1) the root mean square of mean for each detector in low-gain (high-gain) images is better than 0.04 (0.07) in digital number (DN) after dark current correction; (2) the DN relationship between low- and high-gain images conforms to the quadratic polynomial mode; (3) streaking metrics are better than 0.2% after relative calibration; and (4) the nighttime sensor has the same relative correction parameters at different exposure times for the same gain parameters.  
  Address State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China. drli@whu.edu.cn  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1424-8220 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30513817 Approved no  
  Call Number GFZ @ kyba @ Serial 2125  
Permanent link to this record
 

 
Author Jiang, W.; He, G.; Long, T.; Guo, H.; Yin, R.; Leng, W.; Liu, H.; Wang, G. url  doi
openurl 
  Title Potentiality of Using Luojia 1-01 Nighttime Light Imagery to Investigate Artificial Light Pollution Type Journal Article
  Year 2018 Publication Sensors Abbreviated Journal (down) Sensors  
  Volume 18 Issue 9 Pages 2900  
  Keywords Remote Sensing; Instrumentation  
  Abstract The successful launch of Luojia 1-01 complements the existing nighttime light data with a high spatial resolution of 130 m. This paper is the first study to assess the potential of using Luojia 1-01 nighttime light imagery for investigating artificial light pollution. Eight Luojia 1-01 images were selected to conduct geometric correction. Then, the ability of Luojia 1-01 to detect artificial light pollution was assessed from three aspects, including the comparison between Luojia 1-01 and the Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite (NPP-VIIRS), the source of artificial light pollution and the patterns of urban light pollution. Moreover, the advantages and limitations of Luojia 1-01 were discussed. The results showed the following: (1) Luojia 1-01 can detect a higher dynamic range and capture the finer spatial details of artificial nighttime light. (2) The averages of the artificial light brightness were different between various land use types. The brightness of the artificial light pollution of airports, streets, and commercial services is high, while dark areas include farmland and rivers. (3) The light pollution patterns of four cities decreased away from the urban core and the total light pollution is highly related to the economic development. Our findings confirm that Luojia 1-01 can be effectively used to investigate artificial light pollution. Some limitations of Luojia 1-01, including its spectral range, radiometric calibration and the effects of clouds and moonlight, should be researched in future studies.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1424-8220 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 1997  
Permanent link to this record
 

 
Author Gaynor, K.M.; Hojnowski, C.E.; Carter, N.H.; Brashares, J.S. url  doi
openurl 
  Title The influence of human disturbance on wildlife nocturnality Type Journal Article
  Year 2018 Publication Science (New York, N.Y.) Abbreviated Journal (down) Science  
  Volume 360 Issue 6394 Pages 1232-1235  
  Keywords  
  Abstract Rapid expansion of human activity has driven well-documented shifts in the spatial distribution of wildlife, but the cumulative effect of human disturbance on the temporal dynamics of animals has not been quantified. We examined anthropogenic effects on mammal diel activity patterns, conducting a meta-analysis of 76 studies of 62 species from six continents. Our global study revealed a strong effect of humans on daily patterns of wildlife activity. Animals increased their nocturnality by an average factor of 1.36 in response to human disturbance. This finding was consistent across continents, habitats, taxa, and human activities. As the global human footprint expands, temporal avoidance of humans may facilitate human-wildlife coexistence. However, such responses can result in marked shifts away from natural patterns of activity, with consequences for fitness, population persistence, community interactions, and evolution.  
  Address Department of Environmental Science, Policy, and Management, University of California-Berkeley, Berkeley, CA 94720, USA  
  Corporate Author Thesis  
  Publisher AAAS Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29903973 Approved no  
  Call Number IDA @ john @ Serial 1988  
Permanent link to this record
 

 
Author Gaston, K.J. url  doi
openurl 
  Title Lighting up the nighttime Type Journal Article
  Year 2018 Publication Science (New York, N.Y.) Abbreviated Journal (down) Science  
  Volume 362 Issue 6416 Pages 744-746  
  Keywords Commentary  
  Abstract Among the most visually compelling images of the whole Earth have been those created using data obtained at night by astronauts or from satellites. The proliferation in use of electric lighting—including from industrial, commercial, municipal, and domestic sources—is striking. It sketches the spatial distribution of much of the human population, outlining a substantial proportion of the world's coastline, highlighting a multitude of towns and cities, and drawing the major highways that connect them. The data embodied in these nighttime images have been used to estimate and map levels of energy use, urbanization, and economic activity. They have also been key in focusing attention on the environmental impacts of the artificial light at night itself. Explicit steps need to be taken to limit these impacts, which vary according to the intensity, spectrum, spatial extent, and temporal dynamics of this lighting.  
  Address Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, UK. k.j.gaston@exeter.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30442788 Approved no  
  Call Number GFZ @ kyba @ Serial 2058  
Permanent link to this record
 

 
Author Dunster, G.P.; de la Iglesia, L.; Ben-Hamo, M.; Nave, C.; Fleischer, J.G.; Panda, S.; de la Iglesia, H.O. url  doi
openurl 
  Title Sleepmore in Seattle: Later school start times are associated with more sleep and better performance in high school students Type Journal Article
  Year 2018 Publication Science Advances Abbreviated Journal (down) Sci. Adv.  
  Volume 4 Issue 12 Pages eaau6200  
  Keywords Human Health  
  Abstract Most teenagers are chronically sleep deprived. One strategy proposed to lengthen adolescent sleep is to delay secondary school start times. This would allow students to wake up later without shifting their bedtime, which is biologically determined by the circadian clock, resulting in a net increase in sleep. So far, there is no objective quantitative data showing that a single intervention such as delaying the school start time significantly increases daily sleep. The Seattle School District delayed the secondary school start time by nearly an hour. We carried out a pre-/post-research study and show that there was an increase in the daily median sleep duration of 34 min, associated with a 4.5% increase in the median grades of the students and an improvement in attendance.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2375-2548 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2131  
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