Cross-evaluating WRF-Chem v4.1.2, TROPOMI, APEX, and in situ NO 2 measurements over Antwerp, Belgium

Geoscientific Model Development

article

Jean-François Müller¹  Trissevgeni Stavrakou¹  Dominique Fonteyn¹  Frederik Tack¹  Felix Deutsch²  Quentin Laffineur³  Roeland Van Malderen³  Nele Veldeman²  Catalina Poraicu¹ 

[1] Atmospheric Composition Department, Royal Belgian Institute for Space Aeronomy;Environmental Modelling Unit, Flemish Institute for Technological Research;Scientific Division Observations, Royal Meteorological Institute of Belgium

DOI  :  10.5194/gmd-16-479-2023

学科分类：土木及结构工程学

来源: Copernicus Publications

【 摘 要 】

The Weather Research and Forecasting model coupled withChemistry (WRF-Chem) is employed as an intercomparison tool for validatingTROPOspheric Monitoring Instrument (TROPOMI) satellite NO 2 retrievalsagainst high-resolution Airborne Prism EXperiment (APEX) remote sensingobservations performed in June 2019 in the region of Antwerp, a majorhotspot of NO 2 pollution in Europe. The model is first evaluated usingmeteorological and chemical observations in this area. Sensitivitysimulations varying the model planetary layer boundary (PBL)parameterization were conducted for a 3 d period in June 2019, indicatinga generally good performance of most parameterizations againstmeteorological data (namely ceilometer, surface meteorology, and balloonmeasurements), except for a moderate overestimation ( ∼  1 m s −1 ) of near-surface wind speed. On average, all but one of the PBL schemes reproduce the surface NO 2 measurements at stations of the Belgian Interregional Environmental Agency fairly well, although surface NO 2 is generally underestimated during the day (between −4.3  % and −25.1  % on average) and overestimated at night (8.2 %–77.3 %). This discrepancy in the diurnal evolution arises despite (1) implementing a detailed representation of the diurnal cycle of emissions (Crippa et al., 2020) and (2) correcting the modeled concentrations to account for measurement interferences due to NO y reservoir species, which increases NO 2 concentrations by about 20 % during the day. The model is further evaluated by comparing a 15 d simulation with surface NO 2 , NO, CO, and O 3 data in the Antwerp region. The modeled daytime NO 2 concentrations are more negatively biased during weekdays than during weekends, indicating a misrepresentation of the weekly temporal profile applied to the emissions obtained from Crippa et al. (2020). Using a mass balance approach, we determined a new weekly profile of NO x emissions, leading to a homogenization of the relative bias among the different weekdays. The ratio of weekend to weekday emissions is significantly lower in this updated profile (0.6) than in the profile based on Crippa et al. (2020; 0.84). Comparisons with remote sensing observations generally show a good reproduction of the spatial patterns of NO 2 columns by the model. Themodel underestimated both APEX (by ca.  −37  %) and TROPOMI columns (ca.  −25  %) on 27 June, whereas no significant bias is found on 29 June. Thetwo datasets are intercompared by using the model as an intermediateplatform to account for differences in vertical sensitivity through theapplication of averaging kernels. The derived bias of TROPOMI v1.3.1NO 2 with respect to APEX is about −10  % for columns between(6–12)  ×  10 15  molec. cm −2 . The obtained bias for TROPOMI v1.3.1 increases with the NO 2 column, following C APEX = 1.217 C v 1.3 - 0.783   ×  10 15  molec. cm −2 , in line with previous validation campaigns. The bias is slightly lower for the reprocessed TROPOMI v2.3.1, with C APEX = 1.055 C PAL - 0.437   ×  10 15  molec. cm −2 (PAL). Finally, a mass balance approach was used to perform a crude inversion ofNO x emissions based on 15 d averaged TROPOMI columns. The emissioncorrection is conducted only in regions with high columns and highsensitivity to emission changes in order to minimize the errors due to windtransport. The results suggest that emissions increase over Brussels–Antwerp ( +20  %), the Ruhr Valley (13 %), and especially Paris ( +39  %), and emissions decrease above a cluster of power plants in western Germany.

【 授权许可】

CC BY