Two-dimensional Modelling

The Goddard Space Flight Center (GSFC) two-dimensional (2D) model is used in the Atmospheric Chemistry and Dynamics Branch to help understand the physical and chemical processes related to ozone changes in the stratosphere and mesosphere (middle atmosphere). The model domain extends from the south pole to the north pole in latitude and from the ground to about 90 kilometers in altitude. The model includes chemistry (about 40 photodissociation processes and about 110 chemical reactions) involving 52 different atmospheric constituents, vertical and meridional winds, and diffusion processes.

This computer model is used to simulate natural and humankind-related changes in middle atmospheric ozone. Natural ozone changes that have been studied include those related to the 27-day solar rotation, the 11-year solar cycle, solar proton events, relativistic electron precipitations, interannual dynamical variations, volcanic eruptions, supernovae explosions, and gamma-ray bursts. Humankind-related changes that have been studied include those related to the chlorofluorocarbon and halon increases, the nuclear explosion tests in the early 1960s, Space Shuttle and Titan IV rocket launches, a proposed fleet of high speed civil transport planes that would fly in the stratosphere, and the proposed test flights of the National Aerospace Plane.

The model simulation is a realization of our theory of middle atmospheric processes. Comparison of the 2D model output and observational data can therefore either support that theory if there is a good agreement, or point to deficiencies that need to be resolved if there are discrepancies. Sometimes the theoretical understanding is lacking and the comparison serves to revise the theory and the model. Disagreements between the model simulation and data can also be due to problems with the data such as remote sensing retrieval errors. The iterative comparison and revision of models such as the GSFC 2D model and observations is what drives middle atmospheric science forward.

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Stratospheric ozone is affected by anthropogenically caused chlorine and bromine increases, solar cycle ultraviolet flux variations, and the changing sulfate aerosol abundance due to several volcanic eruptions. A study was recently completed, which included all three of these variations, with the GSFC 2D model to predict ozone variations over the 1979 to 1994 period. The model captures much of the variability and downward trend in total ozone that is measured by the Total Ozone Mapping Spectrometer (TOMS) instruments, on Nimbus 7 and on Meteor 3, over this time period.

The model simulations predict a decrease in total ozone of about 4% from 1979 to 1994 due to the chlorine and bromine increases. The changing sulfate aerosol abundances can also significantly affect total ozone with the Mt. Pinatubo eruption computed to cause a decrease in global ozone by about 3% in 1992. Solar ultraviolet flux variations cause increases and decreases in total ozone with computed changes of about 1% from solar maximum to minimum.

Model predictions for the future indicate that total ozone should start to recover from its lowest levels by the late 1990's. Future measurements of ozone are crucial to help quantify the recovery process.

For further discussion of past, present and future trends in ozone see Jackman, et al. (J. Geophys. Res., 101, 28,753-28,767, 1996).

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Observations of ozone by the Solar Backscatter UltraViolet (SBUV) and SBUV/2 instruments also indicate substantial changes in ozone during the period January 1979 to December 1993. The percentage changes in ozone over this time period are illustrated as trends per decade in the top figure above.

These ozone changes are believed to be caused by the increasing chlorine and bromine in the atmosphere over that 15 year time period from humans' production of chlorofluorocarbons (CFCs) and halons. The GSFC 2D model has been used to compute the ozone changes caused by the humankind-produced CFCs and halons over the 1979-93 time period.

The decadal trends predicted from the GSFC 2D model over this time period are given for two different model simulations (Models 1 and 2) in the lower two figures. Model 1 uses standard chemistry while Model 2 includes an added chemical reaction and leads to a smaller downward trend in the upper stratosphere (35-50 km) than computed in Model 1. Both Models 1 and 2 have similarities with the trends calculated from the SBUV and SBUV/2 observations, however, both Models 1 or 2 reveal some differences when compared to the observations.

(This is Figure 1 in Chandra et al. [1995])

Selected Publications

Jackman, C. H., and R. D. McPeters, 2004: "The effect of solar proton events on ozone and other constituents," Solar Variability and its Effects on Climate, Geophys. Mon., 141, 305-319.
Weisenstein, D. K., et al., 2004: "Separating chemistry and transport effects in 2-D models," J. Geophys. Res., 109, 10.1029/2004JD004744.
Melott, A. L., et al., 2004: "Did a gamma-ray burst initiate the late ordovician mass extinction?," Int. J. Astrobiology, 3, 55-61.
Gehrels, N., et al., 2003: "Ozone depletion from nearby supernovae," Astrophys. J., 585, 1169-1176.
Miller, A. J., et al., 2002: "A cohesive total ozone data set from the SBUV(2) satellite system," J. Geophys. Res., 107, 10.1029/2001JD000853.
Fleming, E. L., et al., 2002: "Two-dimensional model simulations of the QBO in ozone and tracers in the tropical stratosphere," J. Geophys. Res., 107, 10.1029/2001JD001146.
Jackman, C. H., et al., 2001: "Northern Hemisphere atmospheric effects due to the July 2000 solar proton event," Geophys. Res. Lett., 28, 2883-2886.
Fleming, E. L., et al., 2001: "Sensitivity of tracers and a stratospheric aircraft perturbation in two-dimensional model transport variations," J. Geophys. Res., 106, 14245-14264.
Jackman, C. H., et al., 2000: "Influence of extremely large solar proton events in a changing stratosphere," J. Geophys. Res., 105, 11659-11670.
Weatherhead, E. C., et al., 2000: "Detecting the recovery of total column ozone," J. Geophys. Res., 105, 22201-22210.
Vitt, F. M., et al., 2000: "Computed contributions to odd nitrogen concentrations in the Earth's polar middle atmosphere by energetic charged particles," J. Atmos. Solar-Terr. Phys., 62, 669-683.
Vitt, F. M., et al., 2000: "A two-dimensional model of thermospheric nitric oxide sources and their contributions to the middle atmospheric chemical balance," J. Atmos. Solar-Terr. Phys., 62, 653-667.
Fleming, E. L., et al., 1999: "Simulation of stratospheric tracers using an improved empirically based two-dimensional model transport," J. Geophys. Res., 104, 23911-23934.
Considine, D. B., et al., 1999: "A Monte Carlo uncertainty analysis of ozone trend predictions in a two-dimensional model," J. Geophys. Res., 104, 1749-1765.
Jackman, C. H., et al., 1998: "A global modeling study of solid rocket aluminum oxide emission effects on stratospheric ozone," Geophys. Res. Lett., 25, 907-910.
Danilin, M. Y., et al., 1998: "Aviation fuel tracer simulation: Model intercomparison and implications," Geophys. Res. Lett., 25, 3947-3950.
Considine, D. B., et al., 1998: "Interhemispheric asymmetry in the 1 mbar O3 trend: An analysis using an interactive zonal mean model and UARS data," J. Geophys. Res., 103, 1607-1618.
Roche, A. E., et al., 1998: "Distribution and seasonal variation of CFCs in the stratosphere: Comparison of satellite global data and a 2-D model," Adv. Space Rev., 21, 1383-1391.
Miller, A. J., et al., 1997: "Information content for ozone trends and solar responses in the stratosphere from Umkehr and SBUV(2) satellite data," J. Geophys. Res., 102, 19257-19263.
Chandra, S., et al., 1997: "The seasonal and long term changes in mesospheric water vapor," Geophys. Res. Lett., 24, 639-642.
Chen, L, et al., 1997: "Sensitivity and uncertainty studies of a two-dimensional middle atmospheric ozone model to chemical reaction rates," J. Geophys. Res., 102, 16201-16214.
Rosenfield, J. E., et al., 1997: "Stratopheric effects of the Mt. Pinatubo aeorosl studied with a coupled two-dimensional model," J. Geophys. Res., 102, 3649-3670.
Jackman, C. H., et al., 1996: "Past, present, and future modeled ozone trends with comparisons to observed trends," J. Geophys. Res., 101, 28,753-28,767, 1996.
Vitt, F. M., and C. H. Jackman, 1996: "A comparison of sources of odd nitrogen production from 1974 through 1993 in the Earth's middle atmosphere as calculated using a two-dimensional model," J. Geophys. Res., 101, 6729-6739, 1996.
Jackman, C. H., et al., 1996: "The space shuttle's impact on the stratosphere: An update," J. Geophys. Res., 101, 12,523-12,529, 1996.
Jackman, C. H., et al., 1995: "Energetic particle precipitation effects on odd nitrogen and ozone over the solar cycle time scale," published in a STEP Working Group 5 Report entitled "The Solar Cycle Variation in the Stratosphere," Editor Lon L. Hood, Department of Planetary Sciences, University of Arizona, Tucson, Arizona, 1995.
Chandra, S., et al., 1995: "Recent trends in ozone in the upper stratosphere: Implications for chlorine chemistry," Geophys. Res. Lett., 22, 843-846, 1995.
Jackman, C. H., et al., 1995: "Two-dimensional and three- dimensional model simulations, measurements, and interpretation of the influence of the October 1989 solar proton events on the middle atmosphere," J. Geophys. Res., 100, 11,641-11,660, 1995.
Fleming, E. L, et al., 1995: "The middle atmospheric response to short and long term solar UV variations: analysis of observations and 2D model results," J. Atmos. Terr. Phys., 57, 333-365, 1995.
Considine, D. B., et al., 1995: "Sensitivity of two-dimensional model predictions of ozone response to stratospheric aircraft: An update," J. Geophys. Res.,100, 3075-3090, 1995.
Considine, D. B., et al., 1994: "Effects of a polar stratospheric cloud parameterization on ozone depletion due to stratospheric aircraft in a two-dimensional model," J. Geophys. Res., 99, 18879-18894, 1994.
Jackman, C. H., 1994: "The impact of emissions from space transport systems on the state of the atmosphere," in Proceedings of an International Scientific Colloquium on Impact of Emissions from Aircraft and Spacecraft Upon the Atmosphere, edited by U. Schumann and D. Wurzel, pp. 366-371, 1994.
Chandra, S., et al., 1993: "Chlorine catalyzed destruction of ozone: Implications for ozone variability in the upper stratosphere," Geophys. Res. Lett., 20, pp. 351-354, 1993.
Jackman, C. H., et al., 1992: "A simulation of the effects of the National aerospace plane testing on the stratosphere using a two-dimensional model," in Proceedings of Fourth International Aerospace Planes Conference, Am. Inst. of Aeronaut. and Astronaut., New York, 1992.
Jackman, C. H., et al., 1991: "The influence of dynamics on two-dimensional model results: Simulations of 14C and stratospheric aircraft NOx injections," J. Geophys. Res., 96, pp. 22,559-22,572, 1991.
Kaye, J. A., et al., 1991: "Two-dimensional model calculation of fluorine- containing reservoir species in the stratosphere," J. Geophys. Res., 96, pp. 12,865-12,881, 1991.
Jackman, C. H., et al., 1991: "Impact of interannual variability (1979-1986) of transport and temperature on ozone as computed using a two- dimensional photochemical model," J. Geophys. Res., 96, pp. 5073-5079, 1991.
Jackman, C. H., et al., 1990: "Effect of solar proton events on the middle atmosphere during the past two solar cycles as computed using a two-dimensional model," J. Geophys. Res., 95, pp. 7417-7428, 1990.
Jackman, C. H., et al., 1989: "The sensitivity of total ozone and ozone perturbation scenarios in a two-dimensional model due to dynamical inputs," J. Geophys. Res., 94, pp. 9873-9887, 1989.
Douglass, A. R., et al., 1989: "Comparison of model results transporting the odd nitrogen family with results transporting separate odd nitrogen species," J. Geophys. Res., 94, pp. 9862-9872, 1989.

Principal Investigator

Charles H. Jackman, NASA GSFC

Co-Investigator

Eric L. Fleming, Science Systems and Applications, Inc.

Back to the Modelling page

Last Updated: 9 December 2004
Author: Charles Jackman (jackman@assess.gsfc.nasa.gov)
Web Curator: Leslie R. Lait (Hughes STX) (lrlait@ertel.gsfc.nasa.gov)
Responsible NASA organization/official: Dr. P. K. Bhartia, Atmospheric Chemistry and Dynamics Branch/Head