# Presentation: 327802

## The Global Modeling Initiative “Combo” CTM - Applications to Analysis of Aura DataAnne Douglass, Richard Stolarski, Susan Strahan, Bryan Duncan, Jose Rodriguez, Steven SteenrodNASA Goddard Space Flight Center  

**“****Simulations-R-Us”**
**To obtain output from GMI-COMBO simulations, contact:**
**Susan Strahan**
**301-614-5993**
**strahan@prometheus.gsfc.nasa.gov**
**OR**
**Jose Rodriguez**
**301-614-5736**
**jrodriguez@**
**code916.gsfc.**
**nasa.gov**

**Comparisons with Tropospheric observations**

**The Global Modeling Initiative Chemistry and Transport Model**
**	****Stratospheric and tropospheric chemical mechanism**
**  ****Standard stratospheric chemical mechanism (Douglass et al., 2004)**
**  ****Tropospheric mechanism - modified version of GEOS-CHEM (Bey et al., 2001)**
**  ****113 species, 315 reactions, 78 photolytic processes**
**    ****Fast JX (a new version of Fast J2, Bian and Prather, 2002)**
**    ****SMVGEAR II**
**    ****Physical Processes described by Duncan et al., ****A Global Modeling Initiative study of the long-range cross tropopause transport of biomass burning pollution using CO measurements from AURA, submitted to JGR**
**    ****Flux-form semi-Lagrangian numerical transport (Lin and Rood 1996)**
**  ****Meteorological input**
**  ****GEOS-4.0.2 General Circulation Model (GCM) [Bloom et al., 2005]**
**  ****GEOS-4 Data Assimilation System (6 hour averages)**
**Boundary Conditions - WMO A2**
** ****Emission Inventories **
** ****fossil fuels, biomass burning, biofuels [Duncan et al., 2006; Duncan et al., 2003; Yevich et al., 2003]**
** ****biogenic emissions [Guenther et al., 1995; Wang et al., 1998]**
** ****lightning emissions [Price and Rind, 1992; Pickering et al., 2001]**

**Comparisons with Stratospheric Observations**
**N****2****O                                                    O****3**

- JAN

- MAR

- 400K

- 600K

- 500K_x0019__x0019__x0019__x0019_

- 750K

- 1150K

- 950K

- 68oS

- 32oS

- 32oN

- 68oN

**Scatter plots for N2O from simulations GMI-DAS and GMI-GCM vs MLS N2O (all binned and averaged using equivalent latitude and potential temperature) show that the upwelling circulation is too strong in both simulations.**

**Latitude/Theta plots for N2O (January and March) show that the isolation and descent in the NH polar vortex are better represented in GMI-GCM than in GMI-DAS.  Stronger-than-observed upwelling is apparent in both simulations.**

**Time/Potential temperature cross sections of the horizontal N2O gradients from GMI-DAS and GMI-GCM show remarkable similarity to those derived from MLS data.  The high latitude gradients from GMI-DAS are generally weaker than observed.**

- Scatter plots for O3 from simulations GMI-DAS and GMI-GCM vs MLS O3 (all binned and averaged using equivalent latitude and potential temperature) show that minimal bias between observed and simulated O3 even for O3 < 1 ppmv .

- Latitude/Theta plots for O3 (January and March) show overall agreement between GMI-DAS and GMI-GCM with MLS data.  The January downward push between 500 and 600K at ~50-60N is reproduced by GMI-DAS.

**Combo-GCM profiles show 3 distinct regions that correspond to the regions identified by *****Hoor et al*****.  The GMI-GCM mixed region has the same thickness in all seasons at extratropical latitudes and matches observations. The GMI-DAS mixed region is much thicker.**

***Hoor et al*****. [ACP, 2004] show a minimum of variability in SPURT aircraft CO profiles in the lowermost stratosphere when plotted on potential temperature surfaces with respect to the dynamical (2 PVU) tropopause (left) . The mixed layer near the tropopause was consistently ~35K thick (from just below the 2 PVU surface to ~25K above) in all seasons and all latitudes in the extratropics.**

**Comparison with Lowermost Stratosphere Observations**

**The horizontal gradients of N2O with respect to equivalent latitude on potential temperature surfaces from GMI-DAS and GMI-GCM (ppbv/degree) reproduce basic features of the MLS observations.  The polar vortex barriers tend to be stronger in MLS N2O and in the GMI-GCM than in GMI-DAS.  **

**The horizontal gradients of O3 with respect to equivalent latitude on potential temperature surfaces reproduce basic features of the MLS observations at middle and high latitudes.  In the tropical lower stratosphere GMI-DAS shows much more structure than MLS O3 or GMI-GCM**

**Time/Potential temperature cross sections of the horizontal O3 gradients from GMI-DAS and GMI-GCM show remarkable similarity to those derived from MLS data.  **

**Probability Distribution Functions (PDFs) help quantify this difference.  In the stratosphere (top) ****GMI-GCM**** and GMI-DAS show similar CO variability.  In the upper tropopshere (bottom) the GMI-GCM and GMI-DAS O3 distributions are similar.  The middle panels show that GMI-DAS CO variability greatly exceeds that of GMI-GCM for a broad region.**

**The MLS ozone at 350K shows almost no seasonal variation in the tropics, a seasonal cycle large winter variability 36-50N (middle), and a seasonal cycle with far less variability at 60-80N (right).  The simulations are above the observations during northern hemisphere summer and closer to observations the rest of the year.  The GMI-GCM (top) and GMI-DAS) produce similar seasonal variations for ozone that match MLS at middle and high latitudes.**

**Hoor et al., Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT, Atmos. Chem. Phys, 4, 1427-1442, 2004.  **

**The October monthly mean ozone from the GMI-GCM simulation displays the same latitudinal structure of the ozone climatology developed by McPeters et al. when the GMI-GCM simulations are sampled and averaged over locations of stations used in the climatology.   **

**The October monthly mean ozone from GMI-GCM displays the same latitudinal structure as the McPeters et al. climatology in the upper troposphere and middleworld.   **

**The latitude/time cross section for ozone from GMI-GCM sampled at stations at 370 hPa displays features of the McPeters et al. climatology **

**Mc Peters, R. D., G. J Labow and J. A. Logan, Ozone climatological profiles for satellite retrieval algorithms, submitted manuscript 2006.**