Implementation of GEM-MACH10, A New Higher-Resolution Version of the Canadian Operational Air Quality Forecast Model

Mike Moran1, Sylvain Ménard2, Radenko Pavlovic2, Sylvie Gravel3, Samuel Gilbert2, Hugo Landry2, Wanmin Gong1, Craig Stroud1, Sunling Gong1, and Qiong Zheng1

1Air Quality Research Division, Environment Canada, Toronto, Ontario, Canada 2Air Quality Modelling Applications Section, Environment Canada, Montreal, Quebec, Canada3Air Quality Research Division, Environment Canada, Montreal, Quebec, Canada

11th CMAS Conference, 15-17 October 2012, Chapel Hill, North Carolina

• Canadian AQ Forecasting System

• Short GEM-MACH15 Overview

• Changes for GEM-MACH10

• Performance of New Model

Talk Outline

• Primary messaging tool is the Air Quality Health Index (AQHI)

• Main target is urban areas > 100,000 population

• GEM-MACH15 AQ / Wx on-line forecast model provides guidance on AQHI component values (NO2, O3, PM2.5) and meteorological fields out to 48 hours

Canadian AQ Forecasting System

• Follows example of Canadian national UV index

• Year-round, health-based, additive, no-threshold, hourly AQ index

• Developed from daily time-series analysis of air pollutant concentrations and mortality data (Stieb et al., 2008, J&AWMA)

• Weighted sum of NO2, O3, & PM2.5 concentrations

• Range from 0 to 10+

Canada’s National Air Quality Health Index (AQHI)

Elements of Cdn AQ Forecasting System

Forecasted future situation- Next 48hr -

Modelled forecast values of O3, PM2.5, NO2

Forecaster (1 desk/forecast region)

Schematic diagram of an AQHI forecast

AQHI = 10/10.4*100*[(exp(0.000871*NO2)-1)+(exp(0.000537*O3) -1)+(exp(0.000487*PM2.5) -1)]

AQHI = 10/10.4*100*[(exp(0.000871*NO2)-1)+(exp(0.000537*O3) -1)+(exp(0.000487*PM2.5) -1)]

Numerical forecast- Next 48 hr - GEM-MACH15

UMOS-AQ

Past & present situation - Last 48 hr -

Real-time observations of O3, PM2.5, NO2

Acronym “GEM-MACH” Stands For

modèle Global Environnemental Multi-échelle –Modélisation de la qualité de l'Air et de la CHimie

et / and

Global Environmental Multiscale model – Modelling Air quality and CHemistry

• GEM-MACH is a multi-scale chemical weather forecast model composed of dynamics and physics (GEM) and on-line chemistry modules

• GEM-MACH15 is a particular configuration of GEM-MACH chosen to meet EC’s operational AQ forecast needs; its key characteristics include:

– limited-area-model (LAM) grid configuration for North America

– 15-km horizontal grid spacing, 58 vertical levels to 0.1 hPa

– 2-bin sectional representation of PM size distribution (i.e., 0-2.5 and 2.5-10 μm) with 9 chemical components

– forecast species include O3, NO2, and PM2.5 needed for AQHI

GEM-MACH and GEM-MACH15

• GEM-LAM15 is EC’s limited-area regional weather forecast model

• GEM-MACH15’s grid points are co-located with GEM-LAM15 grid points

• GEM-LAM15 supplies meteorological initial conditions and lateral boundary conditions to GEM-MACH15

GEM-LAM15 and GEM-MACH15 Grids

GEM-LAM15 core grid (blue); GEM-MACH15 grid (red)

Motivation for GEM-MACH10

• New computers

– 2 new IBM Power7 clusters were delivered to Environment Canada in early 2012 (faster nodes, more nodes)

• “Follow the Leader” (need to stay current)

– GEM-LAM15 meteorological piloting model was to be replaced by GEM-LAM10 in 2012 (including reduction in horizontal grid spacing from 15 to 10 km)

GEM-MACH10 v1.5.0 Characteristics• New version of GEM NWP model source code

• New GEM-MACH grid configuration ( ~5X more Flops):– domain virtually unchanged,

– horizontal grid spacing reduced (15 km to 10 km),

– number of σ-p vertical levels increased (58 to 80),

– met time step reduced (450 s to 300 s),

– chemistry time step unchanged (900 s)

• Change in meteorological piloting model from GEM-LAM15/3D-Var to GEM-LAM10/4D-Var

• Mostly same emissions inventories but improved emissions processing, especially for Canadian emissions

Niveaux GEM-MACH

GEM-MACH15(58 levels)

GEM-MACH10(80 levels)

Lowest 47 levels are identical

Number of CPUs vs. Execution Time

Target time: ~ 30 min

Choice: 960 CPUs = 10 x 12 x 8

Changes to Emissions Processing (1)

• Emissions inventories used:

▪ Canada: new version (2006 base year)

▪ USA: no change (projection to 2012)

▪ Mexico: no change (1999 base year)

▪ Biogenics: no change

• but …

Sommaire des changements apportés au RAQDPS (4)

▪ Corrected and optimized boundary shapefiles

▪ Corrections and improvements to some spatial surrogate fields, including new surrogates for Canadian on-road mobile emissions

▪ Updates to some Canadian temporal profiles

▪ New library of PM speciation profiles and addition of some VOC speciation profiles

▪ Land-use-dependent transportable fraction used to scale fugitive dust emissions

▪ Removal of emissions from shut-down facilities (e.g., Flin Flon, MB)

Changes to Emissions Processing (2)

Example: Changes To Spatial Distribution Of Canadian On-road Mobile Emissions– Improved Representation Of Road Type, One Spatial Surrogate Replaced By Set Of 6 Surrogates

Old New

▪ Emissions fields were prepared on GEM-MACH15 grid with SMOKE, then mass-conserving interpolation was used to transfer them to GEM-MACH10 grid; this approach gave better results than preparation directly on 10-km grid (which suggests that scale dependence of some spatial surrogates is not represented properly)

Changes to Emissions Processing (3)

Difference Between Old and New Emissions (GEM-MACH15 Grid, July, Kt/month)

NO2

SO2

CO

NH3

PM2.5 PMC

GEM-MACH10 Chronology

• June 2009: GEM-MACH15 parallel run begins (2006 Cdn and 2005 U.S. emissions)

• Oct. 2011: New operational version of GEM-MACH15 with new emissions

(2006 Cdn and projected 2012 U.S. emissions)

• June 2012: Start of GEM-MACH10 parallel run with GEM-MACH15

• 3 Oct. 2012: GEM-MACH10 v1.5.0 implementation

Objective Scores – Hourly Values Winters, 2011 and 2012

2012

2011

Objective Scores – Hourly Values Summers, 2011 and 2012

2012

2011

Categorical Scores: O3 Contingency Table GEM-MACH10 vs. GEM-MACH15 – Summer 2012

Canada

U.S.

Hourly Values,80 ppb Threshold

10km | OPS

10km | OPS

Categorical Scores: PM2.5 Contingency Table GEM-MACH10 vs. GEM-MACH15 – Summer 2012

Canada

U.S.

Hourly Values,35 ug m-3 Threshold

10km | OPS

10km | OPS

• GEM-MACH10 v1.5.0, a new, higher-resolution version of Environment Canada’s operational AQ forecast model, was implemented on 3 October 2012

• Horizontal grid spacing on the North American forecast domain has been reduced from 15 to 10 km

• Some improvements in model performance are due to improved emissions processing, but meteorological forecasts have also changed

• The changes in this new version are evolutionary, not revolutionary, and were required in part to keep up with changes to EC’s operational Wx forecast models

Conclusions

Thank you for your attention

2011 Summertime Forecast Avg PMPM2.52.5 (ug/m3)

GM10GM15 OPS

Diff: GM10 - GM15

2011 Summertime Forecast Avg NONO22 (ppb)

GM10GM15 OPS

Diff: GM10 - GM15

2011 Summertime Forecast Avg OO33 (ppb)

Diff: GM10 - GM15

GM15 OPS GM10

2011 Wintertime Forecast Avg PMPM2.52.5 (ug/m3)

Diff: GM10 - GM15

GM15 OPS GM10

2011 Wintertime Forecast Avg NONO22 (ppb)

GM15 OPS GM10

Diff: GM10 - GM15

2011 Wintertime Forecast Avg OO33 (ppb)

GM10GM15 OPS

Diff: GM10 - GM15