Code 916 Participation in the UARS Guest Investigator Program

Analysis of Middle Atmosphere Chemistry and Transport Using UARS Constituent Measurements

Principal Investigator:

S. R. Kawa

Co-Investigators:

• A. Aikin
• D. B. Considine
• A. R. Douglass
• E. L. Fleming
• C. H. Jackman
• J. E. Nielsen
• S. E. Strahan

Abstract

A program has been developed to study the chemical and dynamical processes controlling ozone (O3) in the middle atmosphere by analyzing UARS constituent data in conjunction with multi-dimensional models. The overall objective of the research is to gain a better understanding of the processes which produce observed O3 loss so that more reliable predictions can be made of future anthropogenic changes. The approach is to use models to develop temporal and spatial continuity of the observations in order to apply them to specific atmospheric situations. This approach will enable us to exploit the full power of the combined UARS data set and to tightly constrain the variables of complex systems. The approach will also help to establish consistency among the measurements and develop confidence in using them to address outstanding issues. The models to be used include a three-dimensional (3-D) chemistry/transport model which uses winds and temperatures from data assimilation, a 3-D model with transport winds from a global spectral mechanistic model, two-dimensional models with full chemistry, a trajectory model (with chemistry if needed), and box and steady state models. The primary topics to be addressed are the chemistry of the midlatitude stratosphere, stratospheric winter polar chemistry and its effect on midlatitudes, stratospheric and mesospheric transport, and the effect of external influences on middle atmosphere chemistry (e.g., solar UV, energetic particle input). In addressing a broad range of topics with a central focus on O3, and by using a variety of modeling and analysis tools, we expect the separate components to strengthen each other and to make effective use of the data.

Work-In-Progress

Mid and Upper Stratosphere Nitrogen Budget

Figure 1

Comparison of 3-D chemistry/transport model NO2 values with UARS ISAMS measurements at 3.2 mbar. Upper panel shows model global NO2 field (color contours) calculated for January 11, 1992 at 18 hours GMT. The location of ISAMS measurement soundings which occurred within 1/2 hour of the model time are superimposed (white plus signs). The bottom panel shows NO2 mixing ratios as a function of latitude for the ISAMS measurement points in the top panel and the model values interpolated to the ISAMS sample locations. The solar zenith angle of the measurement points is also given.