Browsing by Author "Bousquet, P"

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    Atmospheric transport and chemistry of trace gases in LMDz5B
    (Copernicus Publications, 2015-02-03) Locatelli, R; Bousquet, P; Hourdin, F; Saunois, M; Cozic, A; Couvreux, F; Grandpeix, JY; Lefebvre, MP; Rio, C; Bergamaschi, P; Chambers, SD; Karstens, U; Kazan, V; van der Laan, S; Meijer, HAJ; Moncrieff, J; Ramonet, M; Scheeren, HA; Schlosser, C; Schmidt, M; Vermeulen, AT; Williams, AG
    Representation of atmospheric transport is a major source of error in the estimation of greenhouse gas sources and sinks by inverse modelling. Here we assess the impact on trace gas mole fractions of the new physical parameterizations recently implemented in the atmospheric global climate model LMDz to improve vertical diffusion, mesoscale mixing by thermal plumes in the planetary boundary layer (PBL), and deep convection in the troposphere. At the same time, the horizontal and vertical resolution of the model used in the inverse system has been increased. The aim of this paper is to evaluate the impact of these developments on the representation of trace gas transport and chemistry, and to anticipate the implications for inversions of greenhouse gas emissions using such an updated model. © Author(s, 2015.
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    Estimation of the molecular hydrogen soil uptake and traffic emissions at a suburban site near Paris through hydrogen, carbon monoxide, and radon-222 semicontinuous measurements.
    (American Geophysical Union, 2009-09-23) Yver, C; Schmidt, M; Bousquet, P; Zahorowski, W; Ramonet, M
    Since June 2006, simultaneous semicontinuous measurements of tropospheric molecular hydrogen (H2), carbon monoxide (CO), and radon-222 (222Rn) have been performed at Gif-sur-Yvette (Paris region), a suburban atmospheric measurement site in France. Molecular hydrogen mixing ratios range from 500 to 1000 ppb, CO mixing ratios vary from 100 to 1400 ppb, and 222Rn concentrations fluctuate from 0 to 20 Bq m−3. The H2 seasonal cycle shows the expected pattern for the Northern Hemisphere with a maximum in spring and a minimum in autumn. We inferred a mean baseline value of 533 ppb with a peak-to-peak amplitude of 30 ppb. Carbon monoxide exhibits a seasonal cycle with a maximum in winter and a minimum in summer. The mean baseline value reaches 132 ppb with a peak-to-peak amplitude of 40 ppb. Radon-222 presents weak seasonal variations with a maximum in autumn/winter and a minimum in spring/summer. The diurnal cycles of H2 and CO are dominated by emissions from nearby traffic with two peaks during morning and evening rush hours. The typical H2/CO emission ratio from traffic is found to be 0.47 ± 0.08 on a molar basis (ppb/ppb). The radon tracer method is applied to nighttime H2 observations to estimate the H2 soil uptake of the nocturnal catchment area of our sampling site. The influences from nocturnal local anthropogenic combustion sources are estimated by parallel measurements of CO at 0.14 × 10−5 g(H2) m−2 h−1. The mean inferred dry deposition velocity is 0.024 ± 0.013 cm s−1 with a seasonal amplitude of 40% at Gif-sur-Yvette. © 2009, American Geophysical Union