Interannual variability in CO and ozone as seen

Interannual variability in CO and ozone as seen by TES and MLS and the GMI Combo model. Jennifer A. Logan, Inna Megretskaia, Lin Zhang, and the GMI, TES, and MLS teams Harvard University NASA/Goddard JPL TES meeting, Feb. 24, 2009.

The Global Modeling Initiative (GMI) ‘Combo’ Model § § § Combo = tropospheric + stratospheric chemical mechanism GEOS-4 meteorological fields 2° x 2. 5° resolution Aura 4 simulation, 2004 -2007 Model output is available to the community for Aura science Output saved along satellite track at overpass times § GFED 2 biomass burning emissions for 2004 -2007 § MEGAN inventory for biogenics § Lightning NOx – regional scaling to average OTD/LIS lightning spatial patterns (Allen and Pickering). § GEOS-Chem similar, without stratospheric chemistry.

Satellite data § TES V 003 § Validated with ozonesondes by Lin Zhang, similar high bias to V 002, 3 -10 ppb. § Filters applied to remove “C-shaped” ozone profiles (Lin Zhang) § Omit data with cloud optical depth >2 for pressure <750 h. Pa § TES AKs and prior applied to model output § Uniform prior used for 30°N-30°S § MLS data V 2. 2 § MLS AKs applied to model (makes very little difference)

Outline § Use TES CO to evaluate model performance in lower troposphere to gain insight into reasons for discrepancies with MLS in the upper troposphere § Can the model match the interannual variability in tropical CO and ozone, and if not, why not?

GMI model compared to CO at NOAA/GMD surface sites in the tropics, 2005 -2006 Data Model

GMI model and MOZAIC aircraft data for CO in the tropics Cairo Abidjan Delhi Caracas Data Model – 2005 Model - 2006 Locations with enough aircraft data for model evaluation

CO in the tropics at ~700 h. Pa, July-Nov. 2005 SH biomass burning season. TES Jul Aug. model-TES Too much export in easterlies in lower trop. , convection N. of equator – similar problems with MOPITT comparisons (Junhua Liu, GEOS-Chem runs) Sep Oct. Nov. Fire emissions too low over Africa

CO in the tropics at ~150 h. Pa, July-Nov. 2005 MLS Jul Aug. Sep Oct. Nov. model-MLS Observed max. over India is missing in model. Model is biased low everywhere, except where is it too high in equatorial band – same problem in LT Model maximum from convection is one month late, implying not enough convection in October.

Time series over region of Asian maximum in UT CO 2005 2006 2007 The UT maximum at 150 h. Pa in June. August is too late in the model. Same problem at 215 h. Pa. Papers on high CO seen by MLS over the Himalayas, and effect of Asian monsoon: Li et al. , 2005, Fu et al. , Randel et al. , Park et al. 2008, 2009

CO in the tropics at ~700 h. Pa, July-Nov. 2006 TES model-TES Similar features to 2005: Jul too much export in equatorial easterlies Aug. too low BB emissions over Africa Sep too high CO near Andes (this appeared with switch to MEGAN biogenic emissions) Oct. Nov. Huge difference in BB emissions from Indonesia (Logan et al. 2008, Nassar et al. 2009)

CO over South America in LT (TES) and UT (MLS) 2005 2006 2007 Bench warm-up GFED CO emissions Model lower than MLS in UT, peaks one month late in 2005 and 2006. Suggest a problem with timing of convection, since LT looks good. Good match with TES in LT in 2005 -2006, GFED too high in 2007 Model w/AK suggests lower CO in Aug. and Sept. 2005 – caused by lack of sensitivity. TES Model w. AK Model w/out AK

S. America - CO from MOPITT and TES in the lower trop. 2005 2006 2007 MOPITT data also show 2006 had lowest CO over S. America in BB season.

CO over Southern Africa in LT and UT 2005 2006 2007 GFED emissions too low over S. Africa, but timing looks OK. UT max. is a month too late over S. Africa also. GFED CO emissions GFED emissions similar each year

CO in the tropics at ~700 h. Pa, Dec. 2005 -April 2006 NH biomass burning season. TES model-TES Dec. Jan Feb. Mar. Apr. High CO near the Andes Largest differences related to BB emissions in N. Africa in March – April.

CO in the tropics at ~700 h. Pa, Dec. 2005 -April 2006 MLS Dec. Jan Feb. Mar. Apr. model-MLS

CO in the tropics at ~700 h. Pa, Dec. 2006 -April 2007 Dec. Jan Feb. Mar. Apr. BB emissions from N. Africa appear to be too high, or transport out of source region too strong. BB CO is transported south and west

CO time series over Equatorial Africa 2005 2006 2007 Model CO decreases a month too soon in LT, implying emissions in February are too low. x GFED CO emissions (N. Africa) Model UT maximum in Feb. -April similar to timing in MLS data. But since CO decreases too soon in the LT, caution is needed in interpreting the MLS comparison.

CO time series over Indonesia 2005 2006 2007 See Nassar et al. (2009) for detailed discussion of Indonesia in late 2005 and 2006 (El Nino).

CO tape recorder, 10ºN- 10ºS MLS Means for 2005 subtracted from time series GMI Combo CO from Indonesian fires The GMI Combo model looks pretty good. Interannual variability driven by CO fire emissions, especially from Indonesia. Interannual variability in emissions in NH fire season apparent (Jan. -April). Update of Schoeberl et al. (GRL, 2006), see also Combo model study of Duncan et al. (JGR, 2007), with GCM met. fields.

Issues with V 003 ozone data (and V 002) Some retrievals had “C-shaped” profiles, identified in V 002 by Helen Worden, in validation with IONS data over N. America. Test devised to remove them. The original C-test removed some valid looking profiles in the tropics over e. g. , North Africa. Lin Zhang devised a better test, based on validation of V 003 data. See example to left.

Ozone in the tropics, July-November, 2005 TES Jul Aug. model Model - TES The worst model agreement globally is in the S. Atlantic in Sept. -Nov. (sonde data shows the same) Sep The problem is confined to Atlantic sector. Oct. Outflow to Indian Ocean is OK Nov.

Ozone in the tropics, July-November, 2006 TES model Model - TES Jul Aug. Sep Oct. Nov. Discrepancies are much smaller in 2006. TES is lower in 2006, and model is higher.

July-November, interannual variability in TES data 2005 2006 2007 Jul Aug. Sep Oct. Nov.

Ozone in Oct 2006, 6º-14ºS TES vertical resolution ~6 km! GMI S. Amer. Africa GMI Ascension Island sondes, 8°S Problem is in LT not UT. Ozone too low over Africa, so outflow from Africa does not supply S. Atlantic with enough ozone in easterlies

Ozone over South America, Nov. 2004 -Dec. 2008 200 h. Pa In the model, ozone is related to lightning NOx (but not so simple) LIS data show more lightning in 2006 than 2005. 500 h. Pa Lightning NOx TES data and OMI/MLS data show higher ozone in the South Atlantic region in 2005 and 2007. Independent data from OMI/MLS confirms the IAV in the TES ozone data. Sept. in red Sauvage et al. , Martin et al. – lightning NOx is main source of ozone in the tropics

Ozone over Southern Africa, Nov. 2004 -Dec. 2008 Lightning NOx Oct.

Ozone in the tropics, Dec. 2005 -April 2006 Dec. Jan Feb. Mar. Apr. Discrepancies smaller than in Sept. – Nov.

North Africa

Indonesia For a detailed analysis of this region using GEOS-Chem, and the effects of the El Nino in late 2006 (and the huge fires in Borneo), see Nassar et al. (2009).

Tropospheric ozone column from TES and OMI/MLS products: OMI total O 3 column - MLS strat. ozone OMI scans, so has better global cover than MLS. Variability in TES and OMI/MLS products is essentially the same. TES column (integrated profile) Schoeberl product (uses trajectories to fill in MLS) Ziemke/Chandra product

Conclusions § Interpretation of MLS CO in upper trop. requires careful analysis of CO data in the lower trop. , as errors in LT propagate to the UT. § Over S. America, S. Africa GEOS-4 max. convection appears to be a month too late, but hard to tell for N. Africa as errors in LT CO. • Need to look at convective mass fluxes in model § TES reveals interannual variability in tropical ozone, but model has problems matching this in S. Atlantic, likely due to lightning NOx. • See poster by Junhua Liu for analysis of model meteorology and NOx in 2005/2006 § TES and OMI/MLS products show similar variability