a multi-platform analysis of the north american reactive

Overview:

1) National Emissions Inventory 1999 (EPA NEI99) A new anthropogenic emissions inventory over the U.S.

2) Export of reactive nitrogen during the ICARTT summer intensive.

GEOS-CHEM MeetingApril 4, 2005

A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive

R. C. Hudman, D. J. Jacob, S. Turquety, ITCT-2K4 science team, INTEX-NA science team

National Emissions Inventory 1999 (NEI99):New GEOS-CHEM anthropogenic emissions over the United States

Currently in GEOS-CHEM:

Emitted anthropogenic species include: CO, NOx, SO2, NH3, C2H6, C3H8, Acetone, ALK4 (C4+ Alkanes), PRPE (C3+ Alkenes), MEK (C4+ ketones)

GEOS CHEM now uses a 1985 inventory which is scaled by trend data.

Source Types*: biogenic, biomass burning, cow, fertilizer, fowl, hogs, household solvents, industrial solvents, other anthropogenic, plane, biofuel, residential fossil fuel, transportation

* red = anthropogenic no biofuels blue = biofuel

EPA releases new emission inventories for the US every three years - .25X.25 gridded product for 1999- Monthly, weekday/weekend (keep diurnal cycle as is in current inventory)- New geographical distributions!


NEI99 BlackGEOS-CHEM Red

Yearly Totals------------------Tracer (Tg) NEI99 GEOS-CHEM-------------------------------------------------NOx 6.15 5.72CO 84.6 73.0SO2 7.95 8.09


Propane, Ethane, Acetone are scaled up to GEOS-CHEM values.Ketones, and Alkenes reduced...but small anyway.

JAN JUN DEC JAN JUN DEC JAN JUN DEC

National Emissions Inventory 1999 (NEI99):CO Comparison

NEI99 CO Emissions for January 1998 CO Emissions for January

1998 - NEI99

66 00

3-3

- Decrease over Western US- Increase over East Coast- Similar trend in NOx!- Important implications for ICARTT

January

25N

30N

35N

40N

45N

50N

55N

The

2) Near-field Production from NOx

1) Continental Boundary Layer (CBL)

3) PAN Decomposition(Far-field production)

0

2

4

6

8

10+Deep Convection (very efficient scavenging f~5%)

Convection Associated with Cyclonic Systems (very efficient scavenging f~15%)

Boundary Layer Venting (f > 20%)

Boundary Layer (strong ozone production in summer)

NARE

The North American influence on global ozone can be separated into 3 components:

The fraction of NOx emitted that is exported as some form of NOy varies with uplift mechanism

A multiplatform analysis of the NA NOy budget during ICARTT:Importance of NOy partitioning, NOy export mechanisms

[Horowitz et al., 1998; Jaeglé et al., 1998; Liang et al., 1998; Stohl et al., 2002; Li et al., 2004; Parrish et al., 2004]

Large number of studies...ICARTT can provide a synthesis

%

ICARTT 0-2 km NOy partitioning: Rapid oxidation of NOx downwind of continent

Hudman, R. C., Jacob, D. J., Turquety, S., and INTEX-NA science team,ITCT2k4 science team

12

10

8

6

4

2

050 100 150 2000100 200 300 500 10001500100 200 300400 400

NOAA ITCT2k4100 200 300 400 50 100 150 2000 100 200 300 400 500 1000 1500

12

10

8

6

4

2

0

NASA INTEX-NA

500

5000

0

0

0

0

0

GEOS-CHEM vs. INTEX-NA and ITCT2k4: Comparison along the flight tracks*

PAN:Newunderestimatein the free trop.

HNO3:Previous overestimatecorrected?

Overestimate of CO and NOx in boundary layerAnthro. sourcebias?

NOx: underestimate above 10 km lightning?

* local, strat, BB filtered

NOy export efficiency, f:Regional differences in export efficiency

NARE region has the lowest f . Is this a result of uplift over water after NOy has been removed in MBL?

Is lower export efficiency from southern U.S. a result of stagnation?

Lower export efficiencies seen than Fall studies...~15%

[NOy] - [NOy]bkd[CO] - [CO]bkd

f =

R= anth. emission ratio ofCO/NOx = 6.15 (NEI - all US avg)

[CO]bkd = 75 ppbv, [NOy]bkd=300 ppt

Reg

ions

xR NARE

OffShoreSOUTH

NE and MidWest

PLUMES DEFINEDAS CObkd + 30 ppbv

Convective NOx issue

boundary layer venting

WCB

GEOS-CHEMcaptures theseexport differences

Proposed Future Work

1) A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive.

2) Impact of North American pollution on global ozone and transatlantic transport

- The complete ICARTT data set is an outstanding data set to provide a synthesis of differences in regional distribution of NOy export and partitioning

- What are the implications of this export of NOy and ozone precursors to global ozone and transatlantic transport?

a multi-platform analysis of the north american reactive

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