Global high-resolution simulations of tropospheric nitrogen dioxide using CHASER V4.0

Abstract

Abstract. We evaluate global tropospheric nitrogen dioxide (NO 2 ) simulations using the CHASER V4.0 global chemical transport model (CTM) at horizontal resolutions of 0.56, 1.1, and 2.8 • . Model evaluation was conducted using satellite tropospheric NO 2 retrievals from the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) and aircraft observations from the 2014 Front Range Air Pollution and Photochemistry Experiment (FRAPPÉ). Agreement against satellite retrievals improved greatly at 1.1 and 0.56 • resolutions (compared to 2.8 • resolution) over polluted and biomass burning regions. The 1.1 • simulation generally captured the regional distribution of the tropospheric NO 2 column well, whereas 0.56 • resolution was necessary to improve the model performance over areas with strong local sources, with mean bias reductions of 67 % over Beijing and 73 % over San Francisco in summer. Validation using aircraft observations indicated that high-resolution simulations reduced negative NO 2 biases below 700 hPa over the Denver metropolitan area. These improvements in high-resolution simulations were attributable to (1) closer spatial representativeness between simulations and observations and (2) better representation of large-scale concentration fields (i.e., at 2.8 • ) through the consideration of small-scale processes. Model evaluations conducted at 0.5 and 2.8 • bin grids indicated that the contributions of both these processes were comparable over most polluted regions, whereas the latter effect (2) made a larger contribution over eastern China and biomass burning areas. The evaluations presented in this paper demonstrate the potential of using a high-resolution global CTM for studying megacity-scale air pollutants across the entire globe, potentially also contributing to global satellite retrievals and chemical data assimilation.

An intercomparison of tropospheric ozone reanalysis products from CAMS, CAMS interim, TCR-1, and TCR-2

“…A high-resolution version of the MIROC-Chem model with a horizontal resolution of T106 (1.1 • × 1.1 • ) was used. Sekiya et al (2018) demonstrated the improved model performance on tropospheric ozone and its precursors by increasing the model resolution from 2.8…”

“…Anthropogenic emissions originate essentially from the MACCity inventory (Granier et al, 2011) with enhanced wintertime CO emissions over Europe and the US (Stein et al, 2014). Monthly specific biogenic emissions originate from MEGAN-MACC (Sindelarova et al, 2014) but using monthly climatological values from 2011 onwards. Daily biomass-burning emissions originate from GFASv1.2 (Kaiser et al, 2013).…”

An inter-comparison of tropospheric ozone reanalysis products from CAMS, CAMS-Interim, TCR-1 and TCR-2

“…A high-resolution version of the MIROC-Chem model with a horizontal resolution of T106 (1.1° x 1.1°) was used. Sekiya et al (2018) (Graedel et al, 1993) for NOx. Emission data for other compounds are taken from the HTAP version 2 and GFED version 4 inventories.…”

Transboundary ozone pollution across East Asia: daily evolution and photochemical production analysed by IASI + GOME2 multispectral satellite observations and models

“…The horizontal resolution corresponds to that of IASI, using for each pixel the UV measurements from the closest GOME-2 pixel (without averaging). Spectra and Jacobians in the IR and UV are respectively simulated by the KOPRA (Karlsruhe Optimized and Precise Radiative transfer Algorithm; Stiller et al, 2002) and VLIDORT (Vector Linearized Discrete Ordinate Radiative Transfer;Spurr, 2006) radiative transfer codes. The effects of clouds and aerosols are partially taken into account by iteratively adjusting offsets for each of the seven spectral microwindows (between 980 and 1070 cm −1 ) used in the IR and effective surface albedos and cloud fractions in the UV (two micro-windows between 290 and 345 nm).…”