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Results from a study on expanding AQHI forecast program to rural areas without air quality monitoring data. Evaluation of model performance and forecaster skill in the absence of observed data. Study conducted in northern New Brunswick.
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Predicting the AQHI without aid of observations: results from the northern New Brunswick study National Air Quality Conference Durham, NC Daniel Jubainville Environment Canada Meteorological Service of Canada Feb 11th, 2014
Objectives of this study • Goal is to expand AQHI forecast program to rural areas without air quality monitoring data • Evaluate model performance for AQHI forecasting in rural areas • Determine forecaster skill in the absence of observed data • Observation data was collected starting in September 2012 and is expected to continue until June 2014
Companion Studies • Spatial AQHI Study – Dalhousie University, using passive and active sampling. (Interim Report available) • PM2.5 and O3 had high temporal and spatial correlation • NO2 had poor correlation across the network • St Valentin, QC – Rural AQHI site Campbellton Montreal Bathurst Edmundston Miramichi St Valentin Grand Falls
Air Quality Health Index: Concept Decouple air quality regulation from provision of health advice Develop an “impact” product, statistically-derived from: Canadian multi-city mortality/morbidity studies of short term health effects Air quality data from historical quality assured/controlled database of the National Air Pollution Surveillance Network (NAPS) Additive risk based on the association of acute health effects and the air pollution mixture (O3, PM and NO2) 3 hour rolling pollutant concentrations averages
Current AQHI Coverage Reaches 65% of Canadians -> 88 forecast locations New Brunswick
Site Overview • Baie des Chaleurs oriented ENE-WSW • Terrain rises 200-250 metres within a few kilometres of shoreline on either side of the bay.
Local Meteorology • Topography strongly influences local meteorological conditions • Air quality and weather data collected from September 14th, 2012 to December 31st, 2013 • Most common wind directions along river valley
Wind Stats, Seasonal14 Sep 2012 to 31 Dec 20135-Minute Average Wind Direction
GEM-MACH Air Quality Model - AQHI Model percent correct within +/-1 AQHI = 98 Positive bias September-October mostly due to over-prediction of O3 Negative bias in colder months due to under-prediction of PM2.5 and NO2, and to a lesser extent O3 The negative bias is due to under-represented local emissions and the limited resolution of the boundary layer i.e. thermal inversions develop overnight during periods of light winds -> pollutants build up Bias in O3 due to seasonal variation not captured by model
Seasonal Performance (=, +/-1): 99% (=, +/-1): 98% (=, +/-1): 98% (=, +/-1): 95%
Forecast – Pilot Project • Atlantic Storm Prediction Centre (ASPC) forecasters asked to generate forecasts starting in January 2013. • Two forecasts per day, issued at 6AM & 5PM AST/ADT. • Forecasts are for maximum expected AQHI per period (Today, Tonight, Tomorrow). • Only issued if operational requirements allow. • Expect forecast availability to be biased towards fair weather situations when operations workload is lower. • Forecasters were not given access to observed data (blind test). • Forecasts ended in November 2013.
Forecasts issued 6:00 AM AST/ADTToday (January 17th – November 4th, 2013) Forecast Model
Forecasts issued 6:00 AM AST/ADTTonight (January 17th – November 4th, 2013) Forecast Model
Forecasts issued 6:00 AM AST/ADTTomorrow (January 17th – November 4th, 2013) Forecast Model
Forecasts issued 5:00 PM AST/ADTTonight (January 17th – November 4th, 2013) Forecast Model
Forecasts issued 5:00 PM AST/ADTTomorrow (January 17th – November 4th, 2013) Forecast Model
Air Quality Events 06Z Feb 26 2013 • Study captured a few events (Long Range Transport, local emissions buildup) • LRT was over-predicted by GEM-MACH, but timing was good. Short time-scale variability not captured. • Trapping of local pollutants under inversions not captured well by GEM-MACH. • Forecasters generally nudged forecast in right direction falling short of removing error. • E.g. 25-26 Feb 2013 GEM-MACH forecast 2/2/2 SPC forecast 3/3/3 Actual AQHI 4/4/3 • Missed smoke events/false alarms
Summary • Campbellton site is representative of a semi-rural centre with the measured AQHI generally in the Low Risk category • GEM-MACH showed skill predicting the maximum AQHI to within ± 1 of observed AQHI ~95% of the time • GEM-MACH positive AQHI bias (due to O3) in the fall became a negative bias in the winter and early spring (due to NO2, PM2.5 and to a lesser degree O3). • Cold season biases are due to under-represented local emissions, stronger inversions and inhibited mixing not fully parameterized in the model boundary layer. • ASPC forecasters generally added value to the GEM-MACH forecast predicting to within ± 1 observed AQHI ~98% of the time • ASPC forecasters generally added value by compensating for model’s cold season bias • ASPC forecasters and model both struggle with extreme events related to forest fire smoke
Acknowledgements Co-authors: Environment Canada – David Waugh, Alan Wilson, Steve Beauchamp, Doug Steeves Dalhousie University – Mark Gibson, Gavin King, James Kuchta Partners: Environment Canada – Craig Stroud, David Anselmo Collège Communautaire du Nouveau-Brunswick Campbellton Campus – Réjean Savoie New Brunswick Environment & Local Government – Darrell Welles, Eric Blanchard Health Canada – Kamila Tomcik, Christina Daly