Technical note: AQMEII4 Activity 1: evaluation of wet and dry deposition schemes as an integral part of regional-scale air quality models

Dry deposition is an important sink of many air pollutants and their precursors. The regional-to-global chemical transport models used to predict and understand air pollution can differ substantially in their simulated dry deposition rates yet understanding of the processes and parameters driving the inter-model spread is poor. Here we introduce an effort from the Air Quality Model Evaluation International Initiative Phase 4 (AQMEII4) aimed at process-oriented evaluation of the dry deposition schemes used in regional chemical transport models. In this effort, dry deposition schemes are configured as standalone single-point models at a diverse set of northern hemisphere locations with observed ozone fluxes. In this paper, we identify the features in the observed ozone deposition velocities that enable a unique testbed. Site-level meteorological and biophysical observations that drive the standalone models are also described. In general, our desire to isolate uncertainties related to the representation of depositional processes and parameters, together with the high computational cost of the regional AQMEII4 air quality models, motivated our use of standalone models. Our design allows for quantifying differences between models across identical conditions at a variety of sites, minimizing input uncertainty in model evaluation, and identifying the responses of different schemes to changing meteorology, biophysics, and ecosystem characteristics. Half of the sites examined have 3-12 years of data, limiting the influence of strong observed interannual variability in ozone deposition velocities on model evaluation. Together with the AQMEII4 effort examining simulations from regional air quality models (Galmarini et al., 2021), the effort described here will advance our understanding of current predictive ability of dry deposition and thus the lifetimes and concentrations of air pollutants.

GALMARINI Stefano;  MAKAR Paul;  CLIFTON Olivia;  HOGREFE Christian;  BASH Jesse O.;  BELLASIO R.;  BIANCONI Roberto;  BIESER J.;  BUTLER Tim;  DUCKER Jason;  FLEMMING Johannes;  HODZIC Alma;  HOLMES Christofer;  KIOUTSIOUKIS Ioannis;  KRANENBURG Richard;  LUPASCU Aurelia;  PEREZ-CAMANYO Juan Luis;  PLEIM Jonathan;  RYU Young-Hee;  SAN JOSE Roberto;  SCHWEDE Donna;  SILVA Sam;  WOLKE Ralf; 

2022-11-25

COPERNICUS GESELLSCHAFT MBH

JRC124091

1680-7316 (online),   

https://acp.copernicus.org/articles/21/15663/2021/,    https://publications.jrc.ec.europa.eu/repository/handle/JRC124091,   

10.5194/acp-21-15663-2021 (online),