Ponente
Descripción
The Michigan-Ontario Ozone Source Experiment (MOOSE) was designed to understand what contributes to ozone exceedance events in the southeastern Michigan and southwestern Ontario border region. Measurements were collected using advance remote sensing and mobile laboratories, which complement the existing hourly network measurements by both counties. High resolution, real-time meteorological and air quality forecasts were conducted by Environment and Climate Change Canada (ECCC) to guide the deployment of the mobile measurements during the field study. The air quality forecasts are based on ECCC’s Global Environmental Multiscale model - Modelling Air quality and Chemistry (GEM-MACH) at 2.5-km grid spacing with the Town Energy Balance (TEB) urban surface parameterization.
In this study, we assess the impact of a new initialization method for the meteorology for each model forecast cycle. A new assimilation at a true 2.5-km grid spacing is now used instead of the prior simple downscaling from the 10-km regional analysis. The model meteorology is nudged to the analysis gradually over a 6-hr window at the start of cycle to avoid introducing instability. The impact of this new analysis method on high-resolution air quality predictions will be illustrated for the MOOSE study period.
We will also show model results for several of the ozone case study periods. We will first evaluate the model performance and then illustrate diagnostic ratios (e.g. radical-loss-via-NOx/total-radical-loss, HCHO/NO2) which can be used to assess ozone production sensitivity to its precursors (VOC and NOx). This will be used to assess whether VOC and/or NOx reductions will be most efficient at reducing ozone for the exceedance periods.
