Scientific Observations Required to Understand the Antarctic Ozone Hole
There is no doubt that we are data limited. While the data base for the total column content of ozone is excellent, we have a very limited data base for temperature and the vertical distribution of ozone, and a data base limited to total column abundances for some of the many chemical species involved.
To help improve our understanding of the processes which are causing Antarctic ozone to decrease, NASA is planning a two-aircraft experiment in order to obtain a data set that can be used to address the probable causes for the phenomenon. The aircraft experiment has been designed to test many of the key aspects of the present theories, but has also been designed to provide a rather complete data base of valuable information even if all the current ideas are incorrect.
The NASA ER-2 aircraft and the DC-8 are ideally suited to study this important problem. The ER-2 is the high altitude research aircraft and will be able to penetrate the ozone hole at the altitudes of the maximum decline in ozone. It will carry a suite of in situ experiments that will provide data on the air mass within the confines of the hole itself.
The DC-8 will be equipped with remote sensors that will map the vertical distributions of ozone and aerosols above the cruising altitude of the aircraft and within the hole. There will also be measurements of the column abundance of NO2, OClO, BrO, ClONO2, HCl, NHO3 and other species. In addition, the DC-8 will carry a number of in situ experiments because this aircraft will attain altitudes associated with the lower extremes of the ozone hole.
The problem can be summarized as a set of science questions, and mission answers from aircraft observations.
- Is there sufficient ClO to sustain a fast enough non O-atom chain or chains?
- What is the extent of Br and BrO?
- What is the morphology of the ozone depletion?
- What are the spatial and temporal correlations of O3 with Clx, NOy, and p.s.c.'s?
- What is the speciation of NOy?
- What is the water vapor mixing ratio?
- What is the extent, T-dependence, size distribution and chemical composition of particulate matter?
- How aged (what is the fraction of recent tropospheric origin) is the air in the cold pool beneath the vortex?
- Is there a coherent pattern to the vertical velocities?
- If spatial and temporal changes in ozone are detected, can the effects of chemistry and dynamics be separated?
- To what extent is the assumption of air parcel integrity justified?
Excerpt from Science and Objectives in Airborne Antarctic Ozone Experiment (AAOE) , 71p, National Aeronautics and Space Administration (NASA), Ames Research Center, 1987.