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Lightning NOx Source Emissions in GEOS-Chem. Lee T. Murray April 12, 2007 3rd GEOS-Chem Users’ Meeting Thanks to: Rynda Hudman, Bob Yantosca, Daniel Jacob, Jennifer Logan, Eric Leibensperger, Folkert Boersma, and others. NOxO 3. Current Annual NO x Source. Tg N/yr. Fossil Fuel Burning. - PowerPoint PPT Presentation
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Lightning NOxLightning NOx Source Source Emissions in GEOS-ChemEmissions in GEOS-Chem
Lee T. MurrayLee T. MurrayApril 12, 2007April 12, 20073rd GEOS-Chem Users’ Meeting3rd GEOS-Chem Users’ MeetingThanks to: Rynda Hudman, Bob Yantosca, Daniel Jacob, Thanks to: Rynda Hudman, Bob Yantosca, Daniel Jacob, Jennifer Logan, Eric Leibensperger, Folkert Boersma, Jennifer Logan, Eric Leibensperger, Folkert Boersma, and othersand others
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Lightning:An Important Source of NOx
[Hudman et al 2007a]
NOx O3
0.0 0.2 0.4 0.6ppbv
0 20 40 60 80 100ppbv
ModelObs
~50Total
0.1-1 (0.4)N2O Degradation
0.7-1 (0.7)Aviation
1-16 (5.5)Soil Emissions
1-20 (5-7)Lightning
4-24 (10)Biomass Burning
28-32 (28)Fossil Fuel Burning
Tg N/yrCurrent Annual NOx Source
[Schumann and Huntrieser 2007]
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Global Lightning DistributionOptical Transient Detector (May 1995 -- Mar
2000)Lightning Imaging Sensor (Dec 1997 --
present)Combined HR Monthly Climatology
flashes / sec / box
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Original Scheme(pre-v7.02.04)
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
LNOx Parameterization
[Pickering 1998]
6 Tg N / yr[Martin et al 2002]
[Price and Rind 1992]
Scaled to CTH
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Flashrate Parameterization
Z_IC
Z_CG
CTH
CC
Flashrate parameterization of Price and Rind [1992]
Fcontinental CTH4.9
Fmarine CTH1.73
IC/CG Ratio parameterization of Price and Rind [1993]
IC-CG Ratio CC4.0
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Alternative Schemes CTH MFLUX PRECON
Ju
ly O
TD
-LIS
J
uly
2004
flashes/sec/box flashes/sec/box flashes/sec/box
flashes/sec/box
• MFLUX and PRECON params [Allen and Pickering 2002] recreate global distribution poorly with GEOS4 fields
• CTH [Price and Rind 1992] (including near-land) fits overall distribution but fails to capture relative flash rates
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Regional Redistribution
• Scaling done at regional level allows model to drive interannual flashrate variability
• “v1” & “v2” redistribution product: 15 monthly regions with
⎟⎟⎠
⎞⎜⎜⎝
⎛
⎟⎟⎠
⎞⎜⎜⎝
⎛
=
Flashes GEOS Global
Flashes GEOSRegion
Flashes OTD Global
Flashes OTDRegion
torScalingFac
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Improvements from RedistNO SCALING REG SCALING
July 2004
OTD-LIS July
Increased Obs-to-Model correlations in lightning flash rate, particularly during summer months
But rectilinear regions create discontinuities and
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Improved Regional Redistributionk-means clustering: Comp. efficient algorithm to allow data-driven regional selection by iteratively minimizing distances between all data and k cluster centroids in an n-dimensional space
k = 20
20 total regions in space and time based on proximity in month, OTD-LIS (1995-2005 avg.) obs, GEOS-Chem output (1995-2005 avg.), and latitude.
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Improved Regional Redistributionk-means clustering: Comp. efficient algorithm to allow data-driven regional selection by iteratively minimizing distances between all data and k centroids in an n-dimensional space
k = 20
20 total regions in space and time based on proximity in month, OTD-LIS (1995-2005 avg.) obs, GEOS-Chem output (1995-2005 avg.), and latitude.
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
Improved Regional Redistributionk-means clustering: Comp. efficient algorithm to allow data-driven regional selection by iteratively minimizing distances between all data and k centroids in an n-dimensional space
k = 20
20 total regions in space and time based on proximity in month, OTD-LIS (1995-2005 avg.) obs, GEOS-Chem output (1995-2005 avg.), and latitude.
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
k-means Clustering
v2 v3
Significant improvement in overall distribution and preventing discontinuities, while drastically reducing annual number of regions from 12 x 15 = 180 (v2) to 20 (v3).
OTD-LIS
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
“Clustered” Redistribution
* 500 mol/fl in the N Midlats [Hudman et al 2007a]* 280 mol/fl in the tropics to match 4.4Tg tropics [Martin et al 2007]
Flashes/km2/6hr
Averaged model to climatology R = 0.92 Avg GC Monthly LNOx 1995-2006
[TgN/yr]
Jan 0.4261
Feb 0.3790
Mar 0.4456
April 0.4479
May 0.5584
June 0.6831
July 0.7654
Aug 0.7262
Sept 0.5587
Oct 0.5524
Nov 0.4916
Dec 0.4349
Total 6.4693
Lee T. MurrayHarvard Atmospheric Chemistry Modeling Group
April 12, 20073rd GEOS-Chem Users’ Meeting
lightning_nox_nl_mod.fIndividual NOx sources : ---=> Use aircraft NOx? : F=> Use lightning NOx? : T => OTD reg redist? : T => OTD local redist?: F => Use CTH param? : T => Use MFLUX param? : F => Use PRECON param?: F
%%% DIAGNOSTIC MENU %%% :ND56: Lightning flashes : 1 all
Category: LFLASH-$Tracer Names: L-RATE, IC-RATE, CG-RATETracer Numbers: 42001, 42002, 42003
Category: NOX-LI-$Tracer Names: NOxTracer Numbers: 1001
input.geos Options Diagnostic Options
