Status of global ozone and CO simulations�-or-�a cautionary tale.

Jennifer Logan, Bob Yantosca, Lee Murray, Rynda Hudman, Prasad Kasibhatla, and many others who contributed updates to emissions.

Thanks also to Inna Megretskaia

3^rd GEOS-Chem Meeting

Harvard, April 11-13, 2007

Recent updates to GEOS-Chem relevant to chemistry �calculations since V7-03-06 (last public release).��Current version at Harvard is V7-04-12�(details on the web page)

Frequent question: When can we get the newest version of the code?

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Simple answer: When it is fully tested (not yet).

Important updates (relevant to chemistry)

Emissions

• MEGAN – biogenic HCs, in V7-03-06 (Barkley, Curci, Millet, 11 am, Thurs.)
• Fossil fuel/industry – EDGAR + regional inventories (JAL, Aaron van Donkelaar, 2 pm, Wed.)
• Biomass burning – GFED2 (Prasad Kasibhatla, 10 am, Thurs)
• New dust emissions (Duncan Fairlie, 3:35 pm, Wed.)

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3. Lightning rescaling to LIS/OTD (Lee Murray, 3:30 pm, Thurs.)

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• Seasonally variable tropopause (Philippe LeSager, noon, Wed.)

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4. Ozone columns for 1979-2005 (Symeon Koumoutsaris, R. Stolarski, S. H. Frith)

Anthropogenic Emissions Update

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• GEOS-Chem emissions use 1985 as a base year
• These are projected forward using national inventories (U.S., Europe, Japan, etc) and national fossil fuel use from CDIAC
• The projection used the same spatial distribution within a country.
• 20 years is a long time to project forward!

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• See Aaron van Donkelaar, 2 pm, Wed. for updates to emissions and scaling.

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• EDGAR 2000 is based on the EDGAR 1995 inventory and updated energy statistics (not a “new improved” product)
• EDGAR 2000 has known flaws, which we try to fix using regional inventories.

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Options to overwrite EDGAR 2000

These options are essential for CO, for which EDGAR is known to be much too low in Asia.

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• EPA, NEI-99 for the U.S.
• EMEP for Europe
• Streets et al. [2006] for CO from China, 2001 (after TRACE-P)
• Streets et al. [2003], 2000, for the rest of Asia
• BRAVO for Mexico

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• We will include updates from Streets and colleagues for Asian emissions for 2000 onwards, when released.

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Default emissions (1995) vs. EDGAR

G-C Uncorrected Corrected

species Default EDGAR EDGAR

==================================

NOx 23.6 27.8 25.2 Tg N

CO 402.5 282.1 370.9 Tg CO

SO2 60.3 67.4 56.3 Tg S

SO4 2.0 1.5 1.4 Tg S

NH3 40.6 40.6 46.3 Tg NH3

GFED2 Inventory for Biomass Burning

• This is now an option in GEOS-Chem
• 1997-2005
• Area burned from MODIS, 2001-2005;

ATSR/VIRS, 1997-2000

• Fuel loads calculated from CASA model, driven by satellite data for NDVI
• Emission factors from Andreae and Merlet with updates

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Van der Werf et al., ACP 6, 3423-3441, 2006.

Giglio et al., ACP 6, 957-974, 2006

NH

SH

N. Africa

SE Asia

S. Africa

Climatological Emissions (black), GFED2 for 2004 (blue) and 2005 (red)

CO Emissions from Biomass Burning

Testing Strategy

• All updates to the code are tested with a one-month benchmark run for July, using meteorological data from GEOS-3.

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• One month is too short to assess changes to longer lived species, including CO, ozone.

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• Year-long benchmarks run for major code versions, from 2004 on, results posted on the web.

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• These were done in 2005 to assess GEOS-3 vs. GEOS-4 on

v7-02-04 (see Wu et al., 2007, Sauvage et al., 2007 for science)

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• New annual benchmarks started/planned in Nov. 2006 to evaluate major changes in lightning, emissions etc.

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• We are not as far along as we had hoped.

??

OH “trend”

We should have done

a longer benchmark

Benchmark plans

Last (successful) year long benchmarks were run in July 2005.

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Planned simulations in Nov. 2006:

• Base case with OLD emissions, lightning etc.
• Add in MEGAN
• Case 1: New lightning
• Case 2. Above + GFED2
• Case 3. Above + new fossil fuel emissions
• etc

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Lin Zhang’s work on INTEX-B revealed decreases in model CO (Lin Zhang, noon, Friday)

• Decreases in CO related to use of MEGAN, new lightning.

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Lightning code was being improved, so benchmarks delayed.

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Our goal was to have simulations completed and analyzed by this meeting.

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Simulations on v.7-04-12 have problems under investigation!

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The best laid schemes o’ mice an’ men gang aft agley �(from “To a Mouse”, by Robert Burns)

• Hindsight is wonderful.
• Everything takes longer than you think.
• What can go wrong will go wrong.
• Hardware fails at the worst possible time.
• Never use the latest version of the code
• Don’t ask for the latest version of the code
• ……..

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Mid-latitude ozone

Old news:

• There have been long standing deficiencies in the simulation of ozone at northern mid-latitudes.
• Ozone peaks too early and is too high in winter/spring.
• Ozone is too low in summer.

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Newer news:

• Increasing lightning at mid-latitudes to 500 moles/flash (x4) gave good agreement with NOx and ozone for INTEX-A (Hudman et al., 2007).

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What does this increase do extra-tropical ozone?

We use the rescaled lightning (Lee Murray)

OZONE and NO₂ for INTEX-NA in the SOUTHEAST U.S. �4 x lightning yield (to 500 mol/flash) matches NO₂ profile and increases ozone by ~10 ppb

Observed Simulated Improved Simulation

Hudman et al., 2007

O₃

NO₂

Ozone at 500 hPa

Red: New L-NOx

Blue: Old L-Nox

Increase in lightning at mid-latitudes improves ozone simulation

Effect of increased lightning NOx at mid-latitudes on mean ozone at 500 hPa

Old L-NOx

New L-NOx

Higher lightning gives improved agreement with mean ozone in summer, but model is too high over S.E. U.S.

Circles are mean ozone from sondes and MOZAIC

Effect of SYNOZ compared to a model with strat. and trop. chem

APRIL

APRIL

JULY

JULY

GMI COMBO model

GEOS-Chem, with SYNOZ

Old lightning

OZONE, 500 hPa

High ozone from SYNOZ

Final Comments

• Be careful what you ask for – you do not want untested code developed under time pressure (in or out of Harvard).

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• The one-month benchmark has its uses, but MUST be done on current met. fields. We should have moved to GEOS-4.

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• Year-long benchmarks must be done for major changes to code that impact longer lived species (e.g., MEGAN).

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• Users should look at the benchmark output (on the web-site).

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• We will post results of new benchmarks with debugged code!

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• Careful evaluation will be needed of GEOS-5 vs. GEOS-4 chemistry simulations (of course).

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