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Satellite nocturnal images of the earth are a useful way to identify urbanisation. Nighttime lights have been used in a variety of scientific contributions, including studies on the identification of metropolitan areas as well as landscapes impacted by urbanization. However, the study of urban systems by nighttime light imagery has had a fundamental limitation to date: the low spatial resolution of satellite sensors. Although the DMSP Operational Linescan System (OLS) has been gathering global low-light imaging data for over 40 years, its 2.7 km/pixel footprint has limited its use for in-depth studies of urban development. The 2011 launch by NASA and the NOAA of the Suomi National Polar Partnership (SNPP) satellite, with the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on board, has led to a significant improvement. This instrument has better spatial resolution (742 m/pixel), on-board calibration, a greater radiometric range, and fewer saturation and blooming problems than DMSP-OLS data. However, it still has considerable limitations for the in-depth study of the area and internal structure of urban systems.The launch of Luojia 1-01 in June 2018 has increased expectations. LJ1-01 is a nano satellite that can obtain high-resolution nocturnal images (130 metres/pixel). The aim of this paper is to analyse, and compare with previous satellites, the new instrument's capacity to delimit the urbanised area and its efficiency in identifying types of urban landscape (compact, dispersed and rurban). The study cases are Barcelona Metropolitan Region (Spain) and Shenzhen City (China). [ABSTRACT FROM AUTHOR]

Today's cities face simultaneous challenges due to rapidly growing populations, urban sprawl, climate change, and environmental pollution which pose a pressure on our traditional urban drinking water supplies. In this context, stormwater could augment our over-drafted urban groundwater resources. However, urban stormwater runoff carries a myriad of dissolved contaminants (e.g., organics, metals, nutrients), which pose a serious risk to the environmental and public health. Moreover, dissolved contaminants of urban origin – such as trace metals and organic compounds of emerging concern – may not be adequately removed by conventional stormwater treatments. Therefore, it is of the utmost importance to fully understand stormwater contaminant presence, transport, and fate in the built environment to design novel or improve conventional treatment systems. To address this knowledge gap, we have conducted 7 field sampling campaigns during storm events at different Barcelona locations (within 3 districts) to investigate contaminant presence in different urban compartments (e.g., roofs, conventional streets with automobile traffic, pedestrian streets, and green infrastructure outlets). Preliminary results have confirmed presence of toxic metals in Barcelona urban rain and stormwater runoff along with significant differences depending on the catchment areas. After a storm event, trace metal concentrations followed the order: roof rain < pedestrian street runoff < conventional street runoff. Additionally, blue-green infrastructures (bioretention systems) had lower mean metal concentrations at the effluent (outlet) than the influents (inlet). Our initial results on metal occurrence in stormwater collected in the city of Barcelona will provide stormwater quality foundation for water agencies, municipalities, and companies in other water-stressed regions with Mediterranean climate. [ABSTRACT FROM AUTHOR]