Randall MartinAaron Van Donkelaar

Chris Sioris Kelly Chance

Evaluating NOx Emission Inventories in North America and Beyond

Yongtao HuArmistead Russell

Jack DibbTom Ryerson

Ron Cohen

UC Berkeley

Bill Brune

Cloud-filtered Tropospheric NOCloud-filtered Tropospheric NO22 Columns Observed from the Columns Observed from the

SCIAMACHY Satellite Instrument SCIAMACHY Satellite Instrument (Data (Data ICARTT) ICARTT)

May-Oct 2004

detectionlimit

Errorweightin

g

EMIS: Emissions Mapping Integration ScienceEMIS: Emissions Mapping Integration ScienceOptimize North American NOOptimize North American NOxx Emissions Emissions

A priori emissions (SMOKE/Russell)

A posteriori emissionsTop-Down Emissions

May-Oct 2004

1015 molecules cm-2

NOx Emissions (SMOKE/G.Tech)SCIAMACHY NO2 Columns

1011 molec N cm-2 s-1

GEOS-CHEM

Aug 2004

CMAQ

North American NOx Emissions (May – October)North American NOx Emissions (May – October)Largest Change in Northeastern US CoastLargest Change in Northeastern US Coast

1011 atoms N cm-2 s-1 1011 atoms N cm-2 s-1 1011 atoms N cm-2 s-1

GEOS-CHEM

(NAPAP Scaled to 1998) SCIAMACHY (2004) SCIAMACHY - NAPAP

7.6 Tg N 8.4 Tg N 0.8 Tg Nr2

= 0.85

Evaluate Top-Down and Bottom-Up NOx InventoriesEvaluate Top-Down and Bottom-Up NOx InventoriesConduct GEOS-CHEM Simulation For Each InventoryConduct GEOS-CHEM Simulation For Each Inventory

Sampled GEOS-CHEM Along Flight TracksSampled GEOS-CHEM Along Flight Tracks

NOx (ppbv)

Simulation with SCIAMACHY – Original NOx Emission Inventory

HNO3 (ppbv)

P-3 Measurements Support Top-Down InventoryP-3 Measurements Support Top-Down InventoryDC-8 Measurements InconclusiveDC-8 Measurements Inconclusive

In Situ

GEOS-CHEM (Bottom-up)

GEOS-CHEM (Top-Down)

New England New England + Gulf Remote

May-Oct 2004

48 Tg N

48 - 38 Tg N

Major Discrepancy in NOx Emissions from MegacitiesMajor Discrepancy in NOx Emissions from Megacities

GEIA 1998

SCIAMACHY Shows Elevated NOx Export from North AmericaSCIAMACHY Shows Elevated NOx Export from North America

May-Oct 2004

SC

IAM

AC

HY

NO

2 (1015

mo

lec cm-2

)G

EO

S-C

HE

M N

O2 (101

5 m

olec cm

-

2)

May-Oct 2004

Explained by Model Bias in Upper Tropospheric NOExplained by Model Bias in Upper Tropospheric NOxx

GEOS-CHEM NO2

Cohen NO2

Errorbars Show 17th and 83rd percentiles

West of -60 degrees lon, “land” East of -60 degrees lon, “ocean”

GEOS-CHEM NO

Brune NO

GEOS-CHEM low by 7.5% in column

GEOS-CHEM low by factor of 2 in column

Thoughts on Using GEOS-CHEM Outside HarvardThoughts on Using GEOS-CHEM Outside Harvard

Support for global and nested 1 degree by 1.25 degree simulation

Some way to enable more rapid release of model updates would help ensure that GEOS-CHEM remains nimble

Wish ListWish List

Thank you to those at Harvard (especially Bob) for being communicative! Would be impossible without this.