TEMIS user workshop, Frascati, 8-9 October 2007

Monitoring of TransatlanticLong Range Transport of Tropospheric NO2

– Observation and Simulation

Bas MijlingBart Dils

Ronald van der ARuud Dirksen

TEMIS user workshop, Frascati, 8-9 October 2007

Part 1Observation

TEMIS user workshop, Frascati, 8-9 October 2007

• Why tropospheric NO2?– Relatively easy to measure

– Relation with tropospheric O3

• Why OMI? – Daily global coverage; high resolution

• Why Atlantic region?– Predominant westerly winds transport air

pollutants from East US to West Europe

Observation LRT with satellites

TEMIS user workshop, Frascati, 8-9 October 2007

Basic mechanism of long range transport

1. Rapid uplift 2. Fast horizontal transport

East Asian outflowof tropospheric NO2

observed by OMI26 May 2007

TEMIS user workshop, Frascati, 8-9 October 2007

Shielding effects of clouds

NO2

ghost

column

NO2

above the

cloudstroposph.

NO2

column

)(4,

,1

TMtrop

ghoststratslsl

obs N

Nw

AMF

NNN

vghostvobs NwNNwN )1()(

AMF

NNN

stratslsl

v

,

Surf. albedo0.02

Cloud at 800 hPa

TEMIS user workshop, Frascati, 8-9 October 2007

Event I: Transatlantic NO2 transport

2-12-2005 3-12-2005

5-12-20054-12-2005

TEMIS user workshop, Frascati, 8-9 October 2007

22-12-2005 23-12-2005

25-12-200524-12-2005

Event II: Transatlantic NO2 transport

TEMIS user workshop, Frascati, 8-9 October 2007

6-2-2007 7-2-2007

9-2-20078-2-2007

Event III: Backflow from Europe

TEMIS user workshop, Frascati, 8-9 October 2007

29-7-2007 30-7-2007

1-8-200731-7-2007

Event IV: Forest fires on the Canaries

TEMIS user workshop, Frascati, 8-9 October 2007

Data quality: OMI collection 3

- Level 0-1: Improved dark current correction

- Level 1-2: Averaged solar irradiance spectrum

- Improved signal to noise ratio (noise floor now at ~0.2 1015 molec/cm2)

- No cross-track gradient (no artifacts at overlapping tracks)

- Still some striping problem (to be corrected for with filter)

Collection 2 Collection 3

TEMIS user workshop, Frascati, 8-9 October 2007

Part 2Observation & Simulation

TEMIS user workshop, Frascati, 8-9 October 2007

OMI observation / FLEXPART simulation

Flexpart, 14 Jan 2007 OMI, 14 Jan 2007

OMI less sensitive to NO2 in lower troposphere

TEMIS user workshop, Frascati, 8-9 October 2007

OMI observation / FLEXPART simulation

Flexpart, 6 Jan 2007 OMI, 6 Jan 2007

TEMIS user workshop, Frascati, 8-9 October 2007

http://www.temis.nl/lrt

- Height dependency- Frequency (seasonality)- Quantify transport

TEMIS user workshop, Frascati, 8-9 October 2007

Future activities

• Reprocessing OMI data using collection 3

• Implementation destriping filter

• New data-format (HDF5 instead of ASCII)

• Other areas (East Asia, South Africa, …)

• Other satellite instruments (GOME-2)

• Quantifying transport

• Correlation with background stations

TEMIS user workshop, Frascati, 8-9 October 2007

Thank you for your attention!

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