Year-end Sale % OFF 
Abstract
We present 2 yr (October 2008 to September 2010) of in situ measurements of molecular hydrogen (H2) and carbon monoxide (CO) sampled at the tall tower of Trainou, France (47.96°N, 02.11°E, 131 masl, sampling height: 50, 100 and 180 m). Radon-222 (222Rn) measurements were added in May 2009. Background seasonal cycles, based on afternoon values, exhibit an amplitude of 45 and 60 ppb for H2 and CO, respectively, for the three different heights (50, 100 and 180 m above ground). The vertical gradient also shows seasonal variations with a maximum (during the night) of 20 and 45 ppb for H2 and CO, respectively.We also observe diurnal cycles for H2 and CO for the three different heights. In the afternoon, the mixing ratios at the three different heights are similar and are comparable with maritime background stations, such as Mace Head (Ireland). The diurnal cycle of 222Rn follows the boundary layer height variations, with maximum values in the morning. Throughout the year but especially in summer and autumn, the H2 mixing ratio shows nighttime depletion, with the lowest values at 06:00 UTC, due to soil uptake and the low boundary layer height. Using a simple box approach and the Radon-Tracer-Method, the H2 deposition velocity is calculated for the catchment area of Trainou.We find a mean value for the H2 deposition velocity of 2.6 ± 0.9 10-2 cm-2 s-1. During wintertime, H2 and CO are sometimes strongly correlated leading to a H2/CO ratio around 0.25. This ratio is lower than the ratio from traffic emissions, thus highlighting the mixing of sources in this area.
Highlights
Since 1958, which saw the first long-term measurements of CO2 at Mauna Loa (Keeling et al, 1976), the global network of stations monitoring atmospheric trace gases has greatly expanded
The 2 weeks shown in Fig. 1 are typical of specific events: in winter, episodes of strong pollution with a high correlation of H2 and carbon monoxide (CO) during a few hours to a few days are observed; 222Rn is correlated with the two other gases sampled at 180 m but to a lesser extent as its variations are solely due to the transport of polluted air masses and is not influenced by local pollution sources
Measurements of H2 and CO have been performed semicontinuously at the tall tower of Trainou since October 2008 and measurements of 222Rn have been conducted since May 2009
Summary
Since 1958, which saw the first long-term measurements of CO2 at Mauna Loa (Keeling et al, 1976), the global network of stations monitoring atmospheric trace gases has greatly expanded. North America and Western Europe are covered by numerous stations; the rest of the globe is covered more sparsely. The objective of these sites is to describe the large-scale exchange of trace gases. Due to the influence of topography on air mass transport and mixing, which results in large representation errors, measurements at mountain sites are difficult to reproduce using large-scale models. Throughout the European project CHIOTTO, a new station called Trainou
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
