A remote sensing study was conducted in year 2006 in four locations of the Metropolitan Area of Mexico City (MAMC). Two of the sites were the same studied back by us in year 2000 and by others in year 1994. A database was compiled containing 11,289 valid measurements for the carbon monoxide (CO), total hydrocarbons (THC), and nitric oxide (NO) exhaust vehicles emissions. Valid measurements were binned for each pollutant by the vehicle specific power (between -5 and 20 kW tonne(-1)) for the 2000 and 2006 databases. The mean average CO, THC, and NO emissions for year 2006 were determined to be 1.10 +/- 0.18 vol.%, 299 +/- 88.4 ppm, and 610 +/- 115.0 ppm, respectively. Matching the vehicle driving patterns of the fleet measured in year 2000 with the emissions factors obtained in this work, allows estimating the trends in the exhaust emissions of vehicles in the MAMC. The adjusted results of the remote sensing study performed in year 2006 shows that the fleet has decrease 22% in CO and 17% in NO emissions, with small change in total hydrocarbons emissions. The improvements could be related with the introduction in year 2001 of vehicles that met tighter emissions standards, particularly for nitrogen oxides.
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http://dx.doi.org/10.1007/s10661-007-9781-4 | DOI Listing |
Nature
January 2025
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
Evaporation or freezing of water-rich fluids with dilute concentrations of dissolved salts can produce brines, as observed in closed basins on Earth and detected by remote sensing on icy bodies in the outer Solar System. The mineralogical evolution of these brines is well understood in regard to terrestrial environments, but poorly constrained for extraterrestrial systems owing to a lack of direct sampling. Here we report the occurrence of salt minerals in samples of the asteroid (101955) Bennu returned by the OSIRIS-REx mission.
View Article and Find Full Text PDFNature
January 2025
Department of Geography and Environmental Science, University of Reading, Reading, UK.
The Casarabe culture (500-1400 CE), spreading over roughly 4,500 km of the monumental mounds region of the Llanos de Moxos, Bolivia, is one of the clearest examples of urbanism in pre-Columbian (pre-1492 CE) Amazonia. It exhibits a four-tier hierarchical settlement pattern, with hundreds of monumental mounds interconnected by canals and causeways. Despite archaeological evidence indicating that maize was cultivated by this society, it is unknown whether it was the staple crop and which type of agricultural farming system was used to support this urban-scale society.
View Article and Find Full Text PDFSci Rep
January 2025
College of Electrical and Information Engineering, Beihua University, Jilin, 132013, China.
Remote sensing images often suffer from the degradation effects of atmospheric haze, which can significantly impair the quality and utility of the acquired data. A novel dehazing method leveraging generative adversarial networks is proposed to address this challenge. It integrates a generator network, designed to enhance the clarity and detail of hazy images, with a discriminator network that distinguishes between dehazed and real clear images.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, Helsinki, FI-00014, Finland; State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, China.
The reliability of land surface phenology (LSP) derived from satellite remote sensing is crucial for obtaining accurate estimates of the phenological response of vegetation to future climate change in urban ecosystems. Differences in phenological definition and extraction methodology using remote sensing can generate systemic errors in estimating the phenological temperature sensitivity to predict the biological response of vegetation. Here, we evaluated the start of the season (SOS), the end of the season (EOS), and the growing season length (GSL) between the Terra and Aqua combined Moderate Resolution Imaging Spectroradiometer (MODIS) Land Cover Dynamics (MCD12Q2) and the Suomi National Polar-Orbiting Partnership NASA Visible Infrared Imaging Radiometer Suite (VIIRS) Land Cover Dynamics (VNP22Q2) over 1470 urban clusters worldwide.
View Article and Find Full Text PDFSci Adv
January 2025
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Torun, Poland.
Measuring low light absorption with combined uncertainty <1 per mil (‰) is crucial for many applications. Popular cavity ring-down spectroscopy can provide ultrahigh precision, below 0.01‰, but its accuracy is often worse than 5‰ due to inaccuracies in light intensity measurements.
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