Upper-Air Inter-Comparison Experiment

Update

Presented By Philippe Peylin

on behalf of

Christopher Pickett – Heaps &

Peter Rayner

Purpose of the experiment…

An inter-comparison of forward transport using a common CO2 flux field

Use of non-surface CO2 data in the cross-validation of atmospheric CO2 inversion models

• Focus on differences in forward simulations

Methodology…

Single (common) CO2 flux field generated from the

Baker et al. 2006 inter-comparison study

inserted in the ATMs

Model CO2 concentration field sampled appropriately

to compare to available CO2 measurements

Available CO2 measurements…

Non-Surface CO2 Airborne Data Archive : Consists of measurements from 39 aircraft campaigns

• 27 short, intensive campaignsE.G. COBRA 2000, 2003, 2004 (Gerbig et al. 2003, Lin et al. 2006 and others),

PEM-WEST A/B (Anderson et al. 1996, Hoell et al. 1997), PEM-TROPICS A/B (Hoell et al. 1999, Raper et al. 2001), BIBLE A (Machida et al. 2003) ), CRYSTAL (Xueref et al. 2004) and others

• 12 long-term, regular campaignsE.G. Matsueda et al. (1999), NOAA/GMA profile data (Stephens et al. in press),

Cape Grim profile data (Pak 2000, Langenfelds et al. 1996, 1999), CARIBIC (Brenninkmeijer et al. 2005) and others

Available CO2 measurements…

Non-Surface CO2 Airborne Data Archive

• Temporal Coverage: 1987 – 2004• Surface Lower Stratosphere

– Majority of data within the free troposphere

• Reasonable Global Coverage– Data concentrated over the Pacific Ocean and North

America

Altitude Variation (surf - ~21km)

Surf 21,6 km

Inter-comparison project: Current Status…

All participating models required to:

Re-grid flux fields onto respective model grids

Run a forward simulation with analysed meteorology from 1988 – 2003 (or part thereof)• Use of ‘real winds’

Sample the model CO2 conc. field at specified spatio-temporal locations

Inter-comparison project: Current Status…

Currently there are 4 participating ATMs

• LSCE: LMDz (P. Bousquet)

• CSIRO: CCAM (C. Pickett – Heaps & R. Law)

• NIES: CCSR (P. Patra) (Not used yet !)

• JMA: CTDM (T. Maki)

• Colorado State Univ. will hopefully become a future participant

Current results are very preliminary (further analysis planed for this year)

Inter-comparison results to date…

Analysis to date based on profile data:

Cape Grim Profile Data– Monthly vertical profiles over Cape Grim from 1991 – 2000,

surface - ~7000m CAR Profile Data

– Weekly vertical profiles flown over CAR from 1992 – 2002, surface - ~7000m

For each profile…• RMS error and mean model bias (average

residual) are calculated

ANNUAL MEAN (TRANSCOM mean flux)RMS ERROR (ppm) RESIDUALS (ppm)Mean SD Mean SD

CCAM 1.34 0.82 -0.06 1.07LMDz 1.28 0.76 -0.69 0.81CTDM-JMA 1.92 0.98 1.46 1.41

DJF MEAN CCAM 1.03 0.51 -0.05 0.83LMDz 1.11 0.53 -0.76 0.64CTDM-JMA 1.55 0.65 1.22 0.85

MAM MEAN CCAM 1.19 0.71 0.45 0.87LMDz 1.09 0.54 -0.59 0.67CTDM-JMA 2.29 1.01 1.97 1.10

JJA MEAN CCAM 1.76 0.96 0.12 1.34LMDz 1.74 0.9 -0.74 1.18CTDM-JMA 2.39 1.2 1.77 1.45

SON MEAN CCAM 1.32 0.79 -0.68 0.77LMDz 1.11 0.74 -0.65 0.58CTDM-JMA 1.45 0.50 0.94 0.69

CCAMLMDzCTDM

CCAMLMDzCTDM

Inter-comparison Results: RMS error/Model Bias average statistics & time-seriesCAR

Inter-comparison Results: RMS error/Resid seasonality CAR

NOTE: Strong seasonality in RMS error in all forward simulations

RMS vs. Mt

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CCAMLMDzCTDM

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Inter-comparison Results: Seasonal Mean Residual Profiles CAR

CI: Confidence Interval of mean model bias for different levels of the atmosphere

NOTE: Seasonal errors in the vertical gradient during summer (June – August)

CCAMCI

LMDzCI

CTDMCI

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Jun-Jul-AugDec-Jan-Feb

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ANNUAL MEAN (TRANSCOM mean flux)RMS ERROR (ppm) RESIDUALS (ppm)Mean SD Mean SD

CCAM 0.63 0.27 -0.06 0.46LMDz 0.38 0.18 -0.13 0.23CTDM-JMA 0.84 0.54 -0.50 0.78

DJF MEAN CCAM 0.55 0.18 -0.13 0.25LMDz 0.38 0.12 -0.08 0.25CTDM-JMA 0.76 0.45 -0.57 0.55

MAM MEAN CCAM 0.76 0.27 -0.49 0.32LMDz 0.26 0.09 -0.04 0.12CTDM-JMA 1.03 0.47 -0.91 0.52

JJA MEAN CCAM 0.63 0.33 -0.01 0.49LMDz 0.47 0.25 -0.19 0.28CTDM-JMA 1.01 0.77 -0.66 0.95

SON MEAN CCAM 0.62 0.28 0.26 0.44LMDz 0.38 0.19 -0.19 0.20CTDM-JMA 0.67 0.39 -0.04 0.70

Inter-comparison Results: RMS error/Model Bias average statistics & time-seriesCAPE GRIM

CCAMLMDzCTDM

CCAMLMDzCTDM

Inter-comparison Results: RMS error/Resid seasonality Cape Grim

NOTE: Strong seasonality in model bias within CCAM/CTDM fwd simul. but reduced seasonality in the LMDz fwd simul.

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CCAMLMDzCTDM

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Inter-comparison Results: Seasonal Mean Residual Profiles Cape Grim

CCAMCI

LMDzCI

CTDMCI

Jun-Jul-Aug

Dec-Jan-Feb Mar-Apr-Mai

Sep-Oct-Nov

Inter-comparison Results: Variation across four modelsNon-Surface CO2 Airborne Data Archive (VERY PRELIMINARY(VERY PRELIMINARY!)

RANGE: 0.05ppm – >1.7ppm (9,000m – 12,000m)

RANGE: 0.04ppm – >2ppm (6000m – 9000m)

Future Plans…

Solve current problems in sampling conc. field with certain ATMs• Inclusion of results from more models

Extend inter-comparison to the entire upper-air archive

Perform extensive analysis of the Non-Surface CO2 Airborne Data Archive

• Statistical/Climatological analysis

THANKS TO:

The LSCE & CMAR• Dr Peter Rayner, Dr Rachel Law, Dr

Philippe Ciais, Dr Philippe Bousquet & Dr Philippe Peylin

All inter-comparison participants All measurement campaign PIs who have

contributed to the data archive

AND… sincere apologies that I am not able to attend the TRANSCOM meeting this year