Browsing by Autor "Rene Gutierrez"

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    Eight years of continuous measurements of atmospheric methane at a high-altitude South American GAW station
    (2023) Marcos Andrade; Michel Ramonet; Laura Ticona; Olivier Lauremt; Paolo Laj; Fernando Velarde; Isabel Moreno; Rene Gutierrez; Ricardo Forno; Luis Blacutt
    <p>Measurements of methane concentrations were made at the Chacaltaya GAW station (16.3ºS, 68.1ºW, 5240m a.s.l.) in the Andean Cordillera from 2015 to date. During this period two high-precision Picarro-CRDS analyzers were used at the station, regularly calibrated with internationally certified gases (WMO X2004A) via the LSCE primary scale. The site has a privileged location not only due to its altitude but also because air masses arriving from the near Altiplano (3 800 m a.s.l.), the Amazon (so-called low-lands), the Pacific Ocean, and the nearby metropolitan area of La Paz/El Alto (~2 million of inhabitants) can be sampled there.  The complex topography of the region represents a challenge for deconvoluting the origin of the air masses and therefore to understanding the sources and/or processes associated with the measurements made at Chacaltaya. Here we show some results based on re-analysis data as well as on high and medium - resolution back trajectories in order to identify the influence of different regions on the station. In addition, satellite products and satellite-derived databases, from TROPOMI and GFED4.1s and WAD2M are used to characterize and interpret daily, seasonal and interannual behavior of the methane concentrations observed in Chacaltaya. The influence of the local atmospheric planetary boundary layer is clearly seen in the measurements, especially in the late morning, but collocated measurements of other atmospheric components such as carbon monoxide or equivalent black carbon have proven that identifying free-tropospheric air masses is not an easy task.  The contributions of the largest human conglomerate of the region are also discussed in this context.</p>
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    Intense transport of smoke to the Central Andes: Insights from a unique set of instruments located in the Bolivian Andean Cordillera
    (2025) Marcos Andrade; Laura Ticona; Fernando Velarde; Decker Guzman; Luis Blacutt; Ricardo Forno; Rene Gutierrez; Isabel Moreno; Fernand Avila; Gaëlle Uzu
    In 2024, Bolivia experienced the worst year of fires since 2002, when Aqua MODIS began collecting data. According to estimates, more than 15 million hectares were burned this year. A sunphotometer sitting in the Bolivian lowlands recorded AOD values higher than two for several continuous days indicating the degradation of the air quality in the region. A unique set of instruments located in the Bolivian Andes recorded the transport of smoke produced by this biomass burning. Very high values of atmospheric tracers like carbon monoxide, equivalent black carbon, and others have been measured as high as 5240 m asl  at the Chacaltaya GAW station (CHC, 16.35ºS, 68.13ºW, 5240 m asl) and other sites around it both in the Altiplano and adjacent high altitude valleys. Although transport to these sites was observed previously, usually the events lasted one or two days. However, in 2024 longer periods of consecutive days with smoke arriving from the lowlands were observed for a second year in a row. Similar high values were observed in CHC in October of 2023, a year with less than half of fires in the country. The conditions that led to the transport of smoke to the mountains in the Andean Cordillera will be discussed, as well as the possible effects of the associated deforestation in terms of water availability for the central Andes.