Adjoint modeling for atmospheric pollution process sensitivity at regional scale

Abstract

[1] During the summer 1998, a strong pollution event was documented over Paris as part of the Etude et Simulation de la Qualité de l'air en Ile-de-France (ESQUIF) project (second intensive observation period (IOP2)). From 7 to 9 August 1998 the pollution event changes from a well-marked ozone plume issued from Paris to a more general pollution over the whole Ile-de-France region. Using a three-dimensional chemistrytransport model and its adjoint part, the sensitivity of ozone, O x , and NO x peaks to model parameters is investigated. For two locations, Paris and a suburban site, the influence of both meteorological and chemical model parameters on the simulated field concentrations is hourly quantified for each day. Processes leading to a urban polluted event are compared. It is shown that the pollutant concentrations are mainly driven by traffic and solvent surface emissions and meteorological parameters such as temperature. Since the adjoint approach is limited to infinitesimal model perturbation, some scenario simulations are carried out to evaluate the linearity of the impact of the most sensitive parameters within the uncertainty range. It is shown that the sensitivities determined from the adjoint approach can be extrapolated until their uncertainty ranges except for the wind speed.

Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

“…The daily maximum concentration shows the highest sensitivity in the emission post-treatment among all the presented cases (| c| = 2.2 ppb). This is consistent with Menut et al (2003) who also found that the afternoon peak concentrations at a typical summertime episode in Paris are very sensitive to the NO emissions change. In the evening (after 15:00 LT) ANN deviates from the observations faster than POST because the afternoon peak in traffic emissions is more pronounced in the AIRPARIF diurnal profile compared to that used in the ECLIPSE processing which represents an average situation of anthropogenic sources hence a smoother variation.…”

“…A previous sensitivity analysis conducted with the same air-quality model showed only small changes in modeled ozone and PM 10 concentrations over the IdF region due to increase in the CTM's vertical resolution (Menut et al, 2013b). On the other hand, Menut et al (2003) showed that vertical diffusivity was one of the most influential parameters to the observed daily peak concentrations of ozone for a typical summertime episode in IdF. Here, we undertake a similar analysis but in a climate modeling framework, where enhanced meteorological bias is expected.…”

“…In Menut et al (2003) it was shown that the sensitivity of ozone concentrations in the afternoon peak hour due to surface emissions was the second largest after the sensitivity associated with meteorology. In Markakis et al (2014) we compared the two approaches as for their ability to correctly represent ozone photo-chemical production under typical anticyclonic summer conditions and also found important differences.…”

“…It is well established that ozone and certain particulate matter species are sensitive to temperature changes (Fiore et al, 2012;Im et al, 2011Im et al, , 2012Jacob and Winner, 2009;Megaritis et al, 2014). Menut et al (2003) using an adjoint model studied the sensitivity of ozone concentrations at the afternoon peak to numerous model processes and inputs for a typical summer episode in Paris and found that temperature and wind speed were the most influential parameters to the observed changes. For our test we utilize meteorological input that stems from a WRF run employing ERA40 reanalysis data over a 0.44 • resolution regional-scale grid (ERA05) and compare it with the REF simulation utilizing climate model meteorology.…”

Air quality assessment for Portugal

“…CHIMERE has been used for several research applications, including sensitivity to anthropogenic or biogenic emissions (e.g., Beekmann and Derognat, 2003;Menut, 2003;Derognat et al, 2003), emission diagnostics (Vautard et al, 2003), or photo-oxidant forecasting over several regions of Europe (namely Italy and Belgium), being the official model for air quality forecasting over France and Paris region (Vautard et al, 2000). Results showed a reasonable skill for daily maximum forecasts of ozone with an averaged root mean square (RMS) error of about 10 ppb and 0.8 of correlation, which is in agreement with the ozone forecast model intercomparison experiment described in Tilmes et al (2002).…”