Abstract: Using nighttime observations from Visible Infrared Imager Radiometer Suite (VIIRS) Day/Night band (DNB), the characteristics of artificial light sources are evaluated as functions of observation conditions, and incremental improvements are documented on nighttime aerosol retrievals using VIIRS DNB data on a regional scale. We find that the standard deviation of instantaneous radiance for a given artificial light source is strongly dependent upon the satellite viewing angle but is weakly dependent on lunar fraction and lunar angle. Retrieval of nighttime aerosol optical thickness (AOT) based on the novel use of these artificial light sources is demonstrated for three selected regions (United States, Middle East and India) during 2015. Reasonable agreement is found between nighttime AOTs from the VIIRS DNB and temporally adjacent daytime AOTs from the AErosol RObotic NETwork (AERONET) as well as from coincident nighttime AOT retrievals from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), indicating the potential of this method to begin filling critical gaps in diurnal AOT information at both regional and global scales. Issues related to cloud, snow and ice contamination during the winter season, as well as data loss due to the misclassification of thick aerosol plumes as clouds, must be addressed to make the algorithm operationally robust.
Keywords: Remote Sensing
Abstract: Landfilling is the most common method for final treatment of municipal solid waste worldwide. Canadians generated 973 kg/cap of waste in 2016, and 73% of that was sent to landfills or incinerators. This study proposes a novel method which combines remote sensing and vector data to rank the suitability of current landfill sites and their area of influence for expansion in Saskatchewan, Canada; where there are currently more than 500 active landfills. This study found that using average normalized data, 55.3% of the land in the study area was suitable or moderately suitable for landfill expansion while 45% of the area was unsuitable for landfill expansion. Polygon 32, an area dominated by agriculture and pasture land, is the most suitable for landfill expansion based on the mean normalized rank and was ranked 9th (out of 39) in terms of standard deviation. Polygon 27 is the least suitable for landfill expansion, having the largest mean normalized rank, and was ranked 38th (out of 39) in terms of standard deviation. This method is advantageous compared to other decision-making tools which rely on expert opinion. This method relies solely on remote sensing and vector data; but is flexible enough that weighting of data sets can be applied by policy makers if so desired. Results show that using remote sensing data and vector data together are capable of capturing distinctly different aspects of the study area, and that vector data can be used as a proxy for imagery where cloud cover is present.
Keywords: Remote Sensing
Abstract: Sustainable Development Goals (SDG) require sustainable urban development and management for better human life quality. Small urban settlements—those with fewer than 500,000 people—are home to 26.5% of the world’s population. Yet, relatively little research attention has been paid to understanding the structure and dynamics of these smaller cities. In this paper, we propose a new concept, micro-urbanization, to fill this knowledge gap, and develop a methodology to characterize and map it using dense remote sensing time series data and landscape pattern metrics. We define micro-urbanization as a process of urban land change that has five primary characteristics: small, patchy, far from main urban areas, with limited geographic connection with existing urban areas and low urban intensity. We apply the method to two rapidly urbanizing countries in Africa, Nigeria and the Democratic Republic of the Congo. Results show that the methodology is capable of detecting micro-urbanization with relatively high spatial and temporal accuracy.
Keywords: Remote Sensing
Abstract: Remote sensing of night lights differs from other sources of remote sensing in its ability to directly observe human activity from space as well as in informing us on a new type of anthropogenic threat, that of light pollution. This special issue focuses on studies which used newer sensors than the Defense Meteorological Satellite Program – Operational Line-Scan System (DMSP/OLS). Most of the analyses focused on data from the Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime sensor (also called the Day/Night Band, or VIIRS/DNB in short), for which the first instrument in the series was launched in 2011. In this editorial, we provide an overview of the 12 papers published in this special issue, and offer suggestions for future research directions in this field, both with respect to the remote sensing platforms and algorithms, and with respect to the development of new applications.
Keywords: Remote Sensing; Commentary
Abstract: Bosscha Observatory is the largest and oldest observatory in Indonesia that has been actively doing astronomical research since 1928. Bosscha Observatory was originally very suitable for observing astronomical objects because of its ideal night sky conditions and covered most of the northern and southern sky areas. However, starting at the end of 1980, the quality of the night sky at Bosscha Observatory has decreased along with the development of cities around the observatory. Therefore, the construction of a new observatory in Indonesia is currently underway, i.e. the Timau National Observatory. One of the main causes of the decreasing quality of the night sky at Bosscha Observatory is light pollution. Light pollution is one form of pollution caused by excessive light outside the room released into the sky, causing an increase in brightness of the night sky. The brightness increasing of the night sky causes relatively faint astronomical object, e.g. Milky Way Galaxy that is difficult to observe. Based on the analysis of the dynamics of light pollution in a radius of 20 km from Bosscha Observatory and at a radius of 90 km from the Timau National Observatory in 2013-2017 using VIIRS-DNB satellite imagery, it is known that there is a wide change in light pollution for the very low, low, medium, high, and very high. The average area of light pollution at a radius of 20 km from Bosscha Observatory for the category of very low, low, medium, high, and very high categories experienced a rate of -41.3 ± 135.2 km2 / year, 5.9 ± 97.2 km2 / year, 15.1 ± 14.6 km2 / year, 18.0 ± 42.6 km2 / year, and 2.1 ± 10.2 km2 / year. The rate of increase in the extent of light pollution for the medium, high, and very high categories occurs south of the Bosscha Observatory, which is towards the city of Bandung. The average area of light pollution in a 90 km radius from the Timau National Observatory for the very low, low, medium, and high categories experienced a rate of 20.8 ± 43.4 km2 / year, -22.1 ± 40.9 km2 / year, 3.0 ± 7.3 km2 / year, and -1.7 ± 7.3 km2 / year. Therefore, the night sky in the 128-268 degrees azimuth direction at Bosscha Observatory is relatively not ideal as a location for observing astronomical objects, and the Timau National Observatory is still relatively ideal as a location for observing astronomical objects, but it is necessary to monitor the dynamics of light pollution in the direction of 207-215 degrees azimuth which leads to Kupang City.
Keywords: Remote Sensing