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

1
National Aeronautics and Space Administration
Simulation of upper troposphere CO2 from
two-dimensional and three-dimensional models Xun
Jiang1, Runlie Shia2, Qinbin Li1, Moustafa T
Chahine1, Edward T Olsen1, Luke L Chen1, Yuk L
Yung2
1Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, CA
91109 2Division of Geological and Planetary
Sciences, California Institute of Technology,
Pasadena, CA 91125
CO2 Vertical Profile
Jan
Apr
Solid GEOS-Chem Dash 2D Caltech/JPL CTM
35N
Jul
Oct
5N
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 2 Vertical profile of CO2 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.
Data and Model
Fig. 2 shows vertical profiles of CO2 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.

• Data
• Aircraft measurements of CO2 from Matsueda et
  al. 2002 and CMDL AIRS retrieved upper
  troposphere CO2 and O3
• Model
• gt 2-D Caltech/JPL Chemistry and Transport
  Model (CTM)
• 10º (latitude) 40 vertical levels
• Transport NCEP Reanalysis Data
• Boundary condition CMDL CO2
• gt 3-D GEOS-CHEM Model
• 2º(latitude) 2.5º (longitude), 30 vertical
  levels
• Transport GEOS4 Meteorological Data
• Boundary condition CMDL CO2
• 
  CO2 sources and sinks

Meridional Circulation Residual Vertical
Velocity

• The latitudinal distribution of AIRS
  tropospheric CO2 agrees reasonably well with
  model and aircraft CO2 from 40ºS to 40ºN. There
  are some longitudinal differences between
  GEOS-Chem and AIRS, which will be investigated in
  the future using inverse modeling.

Figure 6 GEOS-Chem CO2 at 300 hPa in Jan, Apr,
Jul, and Oct of 2003.
Figure 3 (a) Difference of stream function
between GEOS-4 and 2D. Units are m2/s. (b)
Difference of vertical residual velocity between
GEOS-4 and 2D. (c) Vertical profile of vertical
residual velocity at 35ºN. Units are m/s.

• 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.

Comparison of CO2 Between Model and Aircraft Data

Anti-correlation Between AIRS CO2 and O3 In the
South Asia Monsoon Region
Comparison of CO2 Between AIRS Retrieval, Model
and Aircraft Data

• AIRS retrieved CO2 and O3 over 26ºN-30ºN,
  60ºE-120ºE are investigated in July 2003. There
  is a clear anti-correlation between CO2 and O3.
  Correlation coefficient is -0.52.

(a)
(b)
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.
Conclusions
(c)
(d)

• The 2D Caltech/JPL CTM and 3-D GEOS-Chem
  simulations of CO2 mixing ratio show good
  agreements with the Matsueda et al. 2002
  aircraft CO2 data from 35ºS to 35ºN. Both models
  capture the observed seasonal cycle and
  interannual variability of CO2 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 CO2 mixing ratio in the winter
  and spring.
• The latitudinal distribution of AIRS
  tropospheric CO2 agrees reasonably well with
  model CO2 and aircraft CO2 from 40ºS to 40ºN.
• There is a clear anti-correlation between AIRS
  retrieved CO2 and O3 in the South Asia summer
  monsoon region.

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 CO2 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.
Figure 4 AIRS retrieved upper tropospheric CO2
in Jan, Apr, Jul, and Oct of 2003 Chahine et
al., 2005 GRL. Please refer to Chahine et al.
2006 AGU for more detail.
Jet Propulsion Laboratory California Institute of
Technology Pasadena, California
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