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Aubé, M., & Kocifaj, M. (2016). Editorial: Special issue on remote sensing of light pollution. Journal of Quantitative Spectroscopy and Radiative Transfer, 181, 1.
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Okuliarova, M., Molcan, L., & Zeman, M. (2016). Decreased emotional reactivity of rats exposed to repeated phase shifts of light-dark cycle. Physiology & Behavior, 156, 16–23.
Abstract: Disturbed light–dark (LD) cycles are associated with circadian disruption of physiological and behavioural rhythms and in turn with an increased risk of disease development. However, direct causal links and underlying mechanisms leading to negative health consequences still need to be revealed. In the present study, we exposed male Wistar rats to repeated phase shifts of LD cycle and analysed their ability to cope with mild emotional stressors. In experiment 1, rats were submitted to either a regular 12:12 LD cycle (CTRL rats) or 8-h phase delay shifts applied every 2 days for 5 weeks (SHIFT rats). Subsequently, the behaviour was examined in the open-field, black–white box and elevated plus maze tests. In experiment 2, changes in blood pressure (BP), heart rate (HR) as well as the activity of autonomic nervous system were measured in telemeterised rats in response to open-field and black–white box tests before and after 5-week exposure to shifted LD regime. Locomotor activity was consistently higher in SHIFT than CTRL rats in in the open-field and black–white box tests. Interestingly, in the elevated plus maze, SHIFT rats displayed increased risk assessment and decreased grooming compared to CTRL rats. Anxiety measures were affected only in the black–white box, where SHIFT rats displayed reduced anxiety-like behaviour compared to CTRL rats. Differences in behavioural reactivity between SHIFT and CTRL rats did not correspond with BP and HR changes. However, exposure to phase shifts increased the sympathovagal reactivity in the black–white box. Together, our results demonstrated that disturbed LD conditions decreased emotional reactivity of rats and affected their ability to cope with emotional stressors denoting an additional risk mechanism linking disrupted circadian organisation to adverse health effects.
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Kotarba, A. Z., & Aleksandrowicz, S. (2016). Impervious surface detection with nighttime photography from the International Space Station. Remote Sensing of Environment, 176, 295–307.
Abstract: For over two decades nighttime satellite imagery from the Operational Linescan System (OLS) has been used to detect impervious surfaces. However, OLS-based maps suffer from the sensor's coarse resolution (2.7 km/pixel), overglow, and saturation in urban areas, resulting in inaccurate estimates of the extent and degree of impervious surfaces. In order to provide more reliable estimates of impervious surface extent, we used high resolution (~ 10 m/pixel) nighttime photography from the International Space Station (ISS). Focusing on the city of Berlin in Germany, we produced a map of the extent of impervious surfaces. Our classification was 85% accurate for both user and producer measures. Impervious surfaces omitted by ISS photography were mainly transit roads and airport runways, while green areas and water bodies within the city were falsely identified. An analysis based on ISS imagery classified 55.7% of the study area as impervious, which is only 3.9% less than ground truth (while the OLS-based estimate was 40% higher than ground truth). ISS imagery failed to provide reliable information about the degree of imperviousness for individual pixels (± 20% errors); nevertheless it accurately estimated the spatially-averaged degree of imperviousness for the whole study area (30.2% vs. the reference value of 30.1%). These results show that ISS photography is an important source of nighttime imagery for mapping the extent of impervious surfaces, and represents a considerable improvement over OLS capabilities.
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Katz, Y., & Levin, N. (2016). Quantifying urban light pollution -- A comparison between field measurements and EROS-B imagery. Remote Sensing of Environment, 177, 65–77.
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Levin, N., & Phinn, S. (2016). Illuminating the capabilities of Landsat 8 for mapping night lights. Remote Sensing of Environment, 182, 27–38.
Abstract: Remote sensing of night-lights has been enhanced in recent years with the availability of the new VIIRS Day and Night band, the commercial EROS-B satellite and astronaut photographs from the International Space Station. However, dedicated space-borne multispectral sensors offering radiance calibrated night lights imagery are yet to be launched. Here we examined the capabilities of Landsat 8 to acquire night time light images of the Earth. Examining seven night-time Landsat 8 scenes, we found that brightly lit areas in both urban (Berlin, Las Vegas, Nagoya and Tel-Aviv) and gas flares (Basra, Kuwait) areas were detected in all eight bands of Landsat 8. The threshold for detection of lit areas was approximately 0.4 W/m2/μm/sr in bands 1–5 and 8 of Landsat 8. This threshold level was higher than Landsat dark noise levels, and slightly lower than post launch Landsat 8 OLI band dependent noise equivalent radiance difference levels. Drawing on this, we call on the USGS to plan an annual night-time acquisition of urban and gas flares areas globally, and to enable the performance of the future Landsat 10 to be established in a way that it will be sensitive enough to image the Earth at night, thus performing as Nightsat during the night.
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