cmaq sensitivity testing for the eastern united states jeffrey w. stehr department of meteorology...
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CMAQ Sensitivity Testing for the Eastern United States
Jeffrey W. Stehr
Department of Meteorology
University of Maryland
October 22, 2002
Durham, NC, Models-3 Users’ Workshop
Meteorology
THE SIMULATION:Meteorology:
• MM5 using Gayno-Seaman planetary boundary layer scheme
• 24 vertical levels, 12 km (202 x 199) nest inside a 36 km domain
• Analysis nudging to NCEP (Eta) reanalysis
• There are problems with MM5!!!
Meteorology: Modifying MM5
• University of Maryland (Zhang & Zheng) has modified the Blackadar boundary layer scheme to achieve better surface winds and temperatures
• Other PBL schemes do a very poor job of it• These are thunderstorm, hurricane, and
frontal models—who cares about a still, stagnant day?
Meteorology: Winds
• Observations • Modified Blackadar• Winds from other
PBL schemes have essentially nothing to do with reality
• Comparisons by NYDEC
Meteorology: Temperature(modified Blackadar)
0 10 20 30 40 50 60 70 80 90285
290
295
300
0 10 20 30 40 50 60 70 80 901
2
3
4
5
070897 12Z - 071297 00Z
Temperature (K)
Wind Speed (m/s)
Data comparisons By NYDEC
Photochemistry
Emissions:• MEPPS with 1995 National Emissions Trends
Inventory• NOT extrapolated to 1997
CMAQ:• 23 vertical levels, 110 x 80 (East-West x North-South)
12 km horizontal resolution• 72 hours of spinup before July 13• CB4 chemical mechanism, MEBI solver
Measurements
THE AIRCRAFT: Instrumented Cessna-172*Chemistry:
• Ozone, Carbon MonoxideMeteorology:
• Relative humidity, Temperature, Pressure altitude
*Currently, we fly a twin-engine Aztec with CO, O3, SO2, PSAP, T, RH, Palt, nephelometer, Met One counter, streaker—B. Doddridge, L. Marufu, B. Taubman
The domain
Measurement sites
W29
W42
GAIHOL
WAY W05
Measurements
• Examine: July 13-14, 1997
• Four measurement flights
• Ozone data only (CO malfunctioned)
• First show everything, then go back
• Used the old MM5 data!
Gaithersburg, MD07/13/97 06:41 - 06:56 EDT
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KEY:CMAQAircraft
Gettysburg, PA07/13/97 07:29 - 07:42 EDT
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Holbrook, Southwestern PA07/13/97 09:50 - 10:01 EDT
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Waynesburg, Southwestern PA07/13/97 13:21 - 13:32 EDT
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Gettysburg, PA07/13/97 14:53 - 15:33 EDT
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Fallston, MD (NE of Baltimore)07/13/97 16:08 - 16:20 EDT
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Bay Bridge Airport Eastern Shore, July 14
7/14/97 11:48 - 12:07 EDT
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Waynesburg, Southwestern PA7/14/97 13:48 - 13:58 EDT, WAY
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Waynesburg, Southwestern PA07/14/97 16:43 - 16:56 EDT, WAY
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Gettysburg, PA07/14/97 17:33 - 17:48 EDT
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Fallston, MD (NE of Baltimore)07/14/97 19:55 - 20:07 EDT
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Measurements
• July 13, Gettysburg PA—structure in both AM and PM flights, but not quite enough ozone.
• July 13, Fallston MD—may be just outside the Baltimore plume.
• July 14, Bay Bridge Airport—obviously, 12 km resolution just isn’t enough to get the Bay Breeze effects right. Our Met modelers suggest that maybe 2 km resolution will do it, probably 1 km resolution.
AM
PM
Future
• Compare CMAQ simulation results for this run and for a run with the new-and-improved MM5 PBL scheme.
• This should help identify the role played by the boundary layer scheme in these simulations.
Acknowledgements
• Da-Lin Zhang & Weizhong Zheng, UMD MM5 modeling
• Bruce Doddridge, Lackson Marufu, Brett Taubman, UMD aircraft measurements
• Gopal Sistla, NYDEC, comparisons between MM5 and measurements
• Fiscal Support: Maryland Department of the Environment