# Presentation: 114215

## Simulation of upper troposphere CO2 from two-dimensional and three-dimensional models

** **

**Simulation of upper troposphere CO****2**** from two-dimensional and three-dimensional models**
**Xun Jiang**1**, Runlie Shia**2**, Qinbin Li**1**, Moustafa T Chahine**1**, Edward T Olsen**1**, Luke L Chen**1**, Yuk L Yung**2

- National Aeronautics and Space Administration

**Data and Model**

**Data:**
**    ****Aircraft measurements of CO****2**** from Matsueda *****et al*****. [2002] and CMDL; AIRS retrieved upper troposphere CO****2**** and O****3**
**Model:**
**   ****> 2-D Caltech/JPL Chemistry and Transport Model (CTM)**
**     ****10****o ****(latitude); 40 vertical levels**
**     ****Transport: NCEP Reanalysis Data**
**     ****Boundary condition: CMDL CO****2**
**  **
**   ****> 3-D GEOS-CHEM Model**
**     ****2o(latitude) ****×**** 2.5o (longitude), 30 vertical levels**
**     ****Transport: GEOS–4 Meteorological Data**
**     ****Boundary condition: CMDL CO****2**
**                                                             ****CO****2**** sources and sinks**

- This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract
- with the National Aeronautics and Space Administration as well as at a number of other research organizations

**Jet Propulsion Laboratory**
- California Institute of Technology
- Pasadena, California

**Comparison of CO****2**** Between Model **
**and Aircraft Data**

**Figure 1: Aircraft observations between 9 km and 13 km (red dots) [Matsueda *****et al*****., 2002] and modeled CO2 mixing ratios from the GEOS-Chem model averaged at the layer between 9 km and 13 km (solid line) from 2000 to 2004. The panels are for 35********S, 25********S, 15********S, 5********S, 5********N, 15********N, 25********N, and 35********N, respectively. For comparison, the CO2 mixing ratios from the Caltech-JPL 2-D model [Shia***** et al*****. 2006] are shown by dotted lines. **

**The lower boundary conditions for 2D Caltech/JPL CTM and 3D GEOS-Chem are set to ground-based measurements [*****Tans et al*****. 1998]. As shown in Fig. 1, simulated CO****2**** mixing ratios from both models agree well with the aircraft data except at mid-latitudes, where GEOS-Chem results show a low bias [*****Shia***** *****et al*****. 2006].**

**CO****2**** Vertical Profile**

**Figure 2: Vertical profile of CO****2**** computed by the GEOS-Chem (solid line) and the Caltech-JPL 2-D model (dotted line). **
**Upper panel: Latitude = 5********N. Lower panel: Latitude = 35********N.**

- Solid: GEOS-Chem; Dash: 2D Caltech/JPL CTM

- 35N

- 5N

**Meridional Circulation & Residual **
**Vertical Velocity**

**Figure 3: (a) Difference of stream function between GEOS-4 and 2D. Units are m****2****/s. (b) Difference of vertical residual velocity between GEOS-4 and 2D. (c) Vertical profile of vertical residual velocity at 35****o****N. Units are m/s.**

**Comparison of CO****2**** Between AIRS Retrieval, **
**Model and Aircraft Data**

**Figure 4: AIRS retrieved upper tropospheric CO****2**** in Jan, Apr, Jul, and Oct of 2003 [Chahine *****et al*****., 2005 GRL].**
**Please refer to Chahine *****et al.***** [2006 AGU] for more detail.**

**Conclusions**

** ****The 2D Caltech/JPL CTM and 3-D GEOS-Chem simulations of CO****2**** mixing ratio show good agreements with the Matsueda *****et al*****. [2002] aircraft CO****2**** data from 35oS to 35oN. Both models capture the observed seasonal cycle and interannual variability of CO****2 ****in the tropical upper troposphere. Stratosphere and troposphere exchange is likely to be too strong in the GEOS-4 reanalysis data, which can explain in part the difference between GEOS-Chem simulated and aircraft observed CO****2**** mixing ratio in the winter and spring.**
**  **
** ****The latitudinal distribution of AIRS tropospheric CO****2**** agrees reasonably well with model CO****2**** and aircraft CO****2**** from 40oS to 40oN. **
** ****There is a clear anti-correlation between AIRS retrieved CO****2**** and O****3**** in the South Asia summer monsoon region.   **

** ****Stream function derived from GEOS-4 Reanalysis data is much stronger than that from NCEP. Vertical residual velocities are derived from the stream functions. There is more upwelling (downwelling) in the tropics (mid-latitudes) in the winter, which contributes to the difference between GEOS-Chem and aircraft data.**
**  **
**   **

**Anti-correlation Between AIRS CO****2**** and O****3**** **
**In the South Asia Monsoon Region**

** ****AIRS retrieved CO****2**** and O****3**** over 26****o****N-30****o****N, 60oE-120oE are investigated in July 2003. There is a clear anti-correlation between CO****2**** and O****3****. Correlation coefficient is -0.52. **
**  **
**   **

**Figure 7: Normalized AIRS CO2 and O3 from Jul 1, 2003 to Jul, 25, 2003.**
**Please refer to Qinbin *****et al*****. [2006, AGU] for more detail.**

**(a)**

**(b)**

**(c)**

**(d)**

**Fig. 2 shows vertical profiles of CO****2**** simulated by the GEOS-Chem (solid line) and the Caltech-JPL CTM (dotted line) at 5********N (upper panel) and 35********N (lower panel). GEOS-Chem CO2 vertical profiles show a smaller vertical gradient than the Caltech/JPL model at mid-latitudes (35********N), likely due to excessive vertical transport in GEOS-4. **

**Figure 5: Tropospheric CO2 from AIRS (black line) against 2D model (Green line), 3D model forced by CMDL boundary condition (Red line), 3D model forced by CO2 sources and sinks (Orange line), Matsueda aircraft data (Purple dots), and CMDL aircraft data (Blue cross) in Jan, Apr, Jul, and Oct of 2003.**

**Figure 6: GEOS-Chem CO****2**** at 300 hPa in Jan, Apr, Jul, and Oct of 2003.**

- Jan

- Apr

- Oct

- Jul

** ****The latitudinal distribution of AIRS tropospheric CO****2**** agrees reasonably well with model and aircraft CO****2**** from 40oS to 40oN. There are some longitudinal differences between GEOS-Chem and AIRS, which will be investigated in the future using inverse modeling.**

**1****Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109**
**2****Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125**