Transport of ²²²radon to the remote troposphere using the Model of Atmospheric Transport and Chemistry and assimilated winds from ECMWF and the National Center for Environmental Prediction/NCAR

Abstract

Abstract. The Model of Atmospheric Transport and Chemistry (MATCH) is used tosimulate the transport of 222Rn using both European Centre for Medium-Range Weather Forecasts (ECMWF) winds and National Center for Environmental Prediction/National Center for Atmospheric Research (hereafter referred to as NCEP) reanalysis winds. These winds have the advantage of being based on observed winds but have the disadvantage that the subgrid-scale transport processes are not routinely archived. MATCH derives subgrid-scale mixing rates for the boundary layer using a nonlocal scheme and for moist convective mixing using one of two parameterizations (Tiedtke [1989] or Pan and Wu [1997]). This paper describes the ability of the model to recreate mixing rates of 222Rn MATCH increases Rn concentrations in the upper troposphere by 50% compared to not having moist convective mixing, while surface concentrations do not appear to be very sensitive to moist convection. In addition, differences between the upper tropospheric concentrations of radon predicted using the ECMWF and NCEP winds can be 30% for large areas of the globe, due to either differences in the forecast center winds themselves or the moist convective mixing schemes used in conjunction with them. This has implications for model simulations of radiatively and chemically important trace species in the atmosphere.

Optimal estimation of the surface fluxes of methyl chloride using a 3-D global chemical transport model

“…The Model of Atmospheric Transport and Chemistry (MATCH) is an off-line transport model developed at NCAR (Rasch et al, 1997;Mahowald, 1996;Mahowald et al, 1997a, b). In this work, MATCH is driven by NCEP reanalysis meteorology.…”

Australian carbon tetrachloride emissions in a global context

“…Global emissions derived from AGAGE and NOAA global CCl 4 data, by the NOAA 1-box model, [1] the AGAGE 12-box 2-D model [21] and the 3-D MATCH model-Kalman filter [6,20] are shown in Fig. 6.…”

“…7). The 2006 emissions are now estimated to have been ,800 Gg, with [21] NOAA 1-box models [1] and MATCH 3-D model [6,20] ; all model annual emissions are 3-year running means; potential emissions derived from UNEP production data are annual means -see text. [1] (AGAGE, Advanced Global Atmospheric Gases Experiment; NOAA, National Atmospheric and Oceanic Administration; MATCH, Model for Atmospheric Chemistry and Transport; UNEP, United Nations Environment Programme).…”

“…These Australian emissions are lower, although uncertainties overlap, than CCl 4 emissions (320 AE 160 Mg, 1996Mg, -2004 [6] ) estimated for Australia (assuming Australian emissions are 80 % of emissions from Australia plus New Zealand) from AGAGE data by inverse methods using MATCH (Model for Atmospheric Chemistry and Transport), a 3-D Eulerian transport model, (2.8 Â 2.88, 28 levels) and a Kalman filter. [6,20] They are significantly lower than a preliminary version of the AGAGE-MATCH inversion for Australia (2500 AE 1000 Mg) published by United Nations Environment Programme (UNEP) in 2009. [4] This latter inversion was initiated with an unrealistically large prior estimate of Australian CCl 4 emissions based on an economic activity (gross domestic product)-based fraction of global emissions.…”

Evaluation of archived and off-line diagnosed vertical diffusion coefficients from ERA-40 with <sup>222</sup>Rn simulations

“…222 Rn is an excellent tracer to study the transport characteristics on short time scales (hours to weeks) because it has an almost uniform emission rate over land and is only lost through radioactive decay with an e-folding lifetime of about 5.5 days (Dentener et al, 1999;Balkanski and Jacob, 1990;Kritz et al, 1990;Brost and Chatfield, 1989;Polian et al, 1986). Therefore 222 Rn has been used extensively to evaluate parameterisations of convective transport (Mahowald et al, 1997;Allen et al, 1996;Feichter and Crutzen, 1990;Jacob and Prather, 1990) and ABL diffusion (Stockwell and Chipperfield, 1999;Stockwell et al, 1998;Jacob et al, 1997;Lee and Larsen, 1997;Mahowald et al, 1997) in atmospheric models.…”