Operational GEM-MACH15 forecast for CalNex 2010 field campaign

GEM-MACH is Environment Canada's new multi-scale in-line air quality (AQ) forecast system. Its operational regional version, GEM-MACH15, is run twice daily at the Canadian Meteorological Centre to produce 48-hour forecasts over a continental-scale domain with 15-km horizontal grid spacing and 58 vertical levels extending from the surface to 0.1 hPa. During the spring 2010 CalNex field campaign in California, meteorological and air quality output from the GEM-MACH15 00Z runs were interpolated to a polar stereographic grid, encoded in GRIB2 format, and transferred to NOAA daily as part of a model intercomparison and ensemble effort led by NOAA/ESRL/CSD (Stuart.A.McKeen@noaa.gov). The EC forecasts, along with the forecasts from several other participating AQ forecast centres in the U.S., were displayed on a common domain in common formats tailored for the field study (http://www.esrl.noaa.gov/csd/2006/modeleval/).

At the same time, the global version (2x2 degree) of GEM-MACH was run experimentally to produce 5-day real-time global AQ forecasts to examine the impact of long-range transport of air pollutants on the CalNex study area (http://collaboration.cmc.ec.gc.ca/science/arqi/data/GEM-MACH-GLOBAL-FORECASTS/).

In this presentation, the GEM-MACH15 regional forecasts will be compared against available ozone and PM2.5 measurements over the CalNex domain and against GEM-MACH global forecasts.