Person: Zamorano Calvo, Jaime
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First Name
Jaime
Last Name
Zamorano Calvo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Astronomía y Astrofísica
Identifiers
4 results
Search Results
Now showing 1 - 4 of 4
Item Colour remote sensing of the impact of artificial light at night (II): calibration of DSLR-based images from the International Space Station(Remote sensing of environment, 2021) Sánchez de Miguel, Alejandro; Zamorano Calvo, Jaime; Aubé, Martin; Bennie, Jonathan; Gallego Maestro, Jesús; Ocaña González, Francisco; Pettit, Donald R.; Stefanov, William L.; Gaston, Kevin J.Nighttime images taken with DSLR cameras from the International Space Station (ISS) can provide valuable information on the spatial and temporal variation of artificial nighttime lighting on Earth. In particular, this is the only source of historical and current visible multispectral data across the world (DMSP/OLS and SNPP/VIIRS- DNB data are panchromatic and multispectral in the infrared but not at visible wavelengths). The ISS images require substantial processing and proper calibration to exploit intensities and ratios from the RGB channels. Here we describe the different calibration steps, addressing in turn Decodification, Linearity correction (ISO dependent), Flat field/Vignetting, Spectral characterization of the channels, Astrometric calibration/georeferencing, Photometric calibration (stars)/Radiometric correction (settings correction - by exposure time, ISO, lens transmittance, etc) and Transmittance correction (window transmittance, atmospheric correction). We provide an example of the application of this processing method to an image of Spain.Item Effects of the COVID-19 lockdown on urban light emissions: ground and satellite comparison(Remote Sensing, 2021) Bustamante-Calabria, Máximo; Sánchez de Miguel, Alejandro; Martín-Ruiz, Susana; Ortiz, Jose-Luis; Vílchez, José M.; Pelegrina, Alicia; García, Antonio; Zamorano Calvo, Jaime; Bennie, Jonathan; Gaston, Kevin J.'Lockdown' periods in response to COVID-19 have provided a unique opportunity to study the impacts of economic activity on environmental pollution (e.g., NO2, aerosols, noise, light). The effects on NO2 and aerosols have been very noticeable and readily demonstrated, but that on light pollution has proven challenging to determine. The main reason for this difficulty is that the primary source of nighttime satellite imagery of the earth is the SNPP-VIIRS/DNB instrument, which acquires data late at night after most human nocturnal activity has already occurred and much associated lighting has been turned off. Here, to analyze the effect of lockdown on urban light emissions, we use ground and satellite data for Granada, Spain, during the COVID-19 induced confinement of the city's population from 14 March until 31 May 2020. We find a clear decrease in light pollution due both to a decrease in light emissions from the city and to a decrease in anthropogenic aerosol content in the atmosphere which resulted in less light being scattered. A clear correlation between the abundance of PM10 particles and sky brightness is observed, such that the more polluted the atmosphere the brighter the urban night sky. An empirical expression is determined that relates PM10 particle abundance and sky brightness at three different wavelength bands.Item The nature of the diffuse light near cities detected in nighttime satellite imagery(Scientific reports, 2020) Sánchez de Miguel, Alejandro; Kyba, Christopher C. M.; Zamorano Calvo, Jaime; Gallego Maestro, Jesús; Gaston, Kevin J.Difuse glow has been observed around brightly lit cities in nighttime satellite imagery since at least the frst publication of large scale maps in the late 1990s. In the literature, this has often been assumed to be an error related to the sensor, and referred to as “blooming”, presumably in relation to the efect that can occur when using a CCD to photograph a bright light source. Here we show that the efect seen on the DMSP/OLS, SNPP/VIIRS-DNB and ISS is not only instrumental, but in fact represents a real detection of light scattered by the atmosphere. Data from the Universidad Complutense Madrid sky brightness survey are compared to nighttime imagery from multiple sensors with difering spatial resolutions, and found to be strongly correlated. These results suggest that it should be possible for a future space-based imaging radiometer to monitor changes in the difuse artifcial skyglow of cities.Item Evolution of brightness and color of the night sky in Madrid(Remote Sensing, 2021) Robles, José; Zamorano Calvo, Jaime; Pascual Ramírez, Sergio; Sánchez de Miguel, Alejandro; Gallego Maestro, Jesús; Gaston, Kevin J.Major schemes to replace other streetlight technologies with Light-Emitting Diode (LED) lamps are being undertaken across much of the world. This is predicted to have important consequences for nighttime sky brightness and color. Here, we report the results of a long-term study of these characteristics focused on the skies above Madrid. The sky brightness and color monitoring station at Universidad Complutense de Madrid (inside the city) collected Johnson B, V, and R sky brightness data, Sky Quality Meter (SQM), and Telescope Encoder Sky Sensor-WiFi (TESS-W) broadband photometry throughout the night, every night between 2010–2020. Our analysis includes a data filtering process that can be used with other similar sky brightness monitoring data. Major changes in sky brightness and color took place during 2015–2016, when a sizable fraction of the streetlamps in Madrid changed from High-Pressure Sodium (HPS) to LEDs. The sky brightness detected in the Johnson B band darkened by 14% from 2011 to 2015 and brightened by 32% from 2015 to 2019.