Long-range transport of NOy and O

3

Thomas WalkerDalhousie UniversityDepartment of Physics & Atmospheric Science

December 6, 2006

What effect do increasing Asian NO

x emissions have on air

quality in the Pacific?

DC8:● TD-LIF (NO

2, PN's, HNO

3)

● SAGA (HNO3)

● O3

C130:● NO

x/NO

y/O

3

● PAN-CIGARette

DC8 Campaign Average Vertical Profiles: Ozone

DC8 Campaign Average Vertical NOy Composition Profile

C130 Campaign Average Vertical Profiles: Ozone

C130 Campaign Average Vertical NOy Composition Profile

“Streets”replace “standard” emissions with Streets inventory over Asia [~7.50 Tg N/yr]

Δ Emissions [Tg N/yr]

“Standard”use latest scaling for lightning and biomass burning [~7.64 Tg N/yr]

Emissions [Tg N/yr]

“No Asia”turn off Asian fossil fuel emissions entirely

Emissions [Tg N/yr]

Fractional Change in Model Due to Change in Asian Emissions

Fractional Change in Model Due to Turning Off Asian Emissions

Lightning's Contribution

Comparison to Ozone Monitoring Instrument (OMI)

OMI compared to model

● Summary

●O3 in model biased 5-10 ppb low relative to aircraft

●O3 columns in model low relative to OMI

●Significant contributions from lightning and Asian transport

●HNO3 in model biased high relative to aircraft

●HNO3 profile in model sensitive to changes in Asian emissions

● Future Work

●Further decomposition of O3 columns: biomass burning, local srcs

●Comparison of model NO2 to OMI

●Examine potential HNO3 sinks: uptake on dust

Special thanks to:Atmospheric Chemistry Analysis Group

Randall MartinBastien SauvageRong-Ming Hu

Lok LamsalBetty Croft

Aaron van DonkelaarNeil Moore

Gray O'ByrneBalagopal Pillai

Thank You for listening!

References● Jacob, D. Introduction to Atmospheric Chemistry. Princeton University Press, 1999.

● Martin, R.V. et al. Space-based constraints on the production of nitric oxide by lightning. Submitted to JGR, 2006.

● Hudman, R.C. et al. Surface and lightning sources of nitrogen oxides over the United States: magnitudes, chemical evolution, and outflow. Submitted to JGR, 2006.

DC8 Vertical Profiles: NOx

DC8 Vertical Profiles: HNO3

DC8 Vertical Profiles: PNs

C130 Vertical Profiles: NOx

C130 Vertical Profiles: HNO3

C130 Vertical Profiles: PNs

Standard features:● Assimilated meteorology (GEOS-4)● NOx-Ox-HC tropospheric chemistry● 4x5 resolution (for expediency)● 30 vertical levels, parametrized strat● Planeflight diagnostic

Model version v7-04-10Recent updates include:● Near-land lightning parametrization● High-latitude lightning rescaling● Rescaling of biomass burning emissions● Use of Streets inventory

Ref: Richter et al. 2005.

Increase in Asian NO2 columns observed from GOME/SCIAMACHY

Long-range transport

Deposition

Rate-limiting step is rxn ofNO w. HO2 radical

P(O3)

NOx-limited: P(O3) goes as [NO]HC-limited: P(O3) goes as [RH]/[NO2]

P(O3)

N2O NO NO2

N2O5

HNO3

PAN

NOx

NOy

OMI compared to “standard” model

● Motivation

● Modelling

●Introduction to GEOS-CHEM

●Comparison of measurements to standard model

●Description of model experiments

●Results from model experiments

● Satellite

●Comparison of model to OMI Ozone

● Summary and future directions