Atmospheric ozone

OH vertical column abundances have been measured since 1977. Based on this long-term data base, the terrestrial OH abundance trends, such as the high-sun (secX = 1) enhancement of the zenith angle dependence, seasonal variations, and diurnal behaviors, have been observed. Current atmospheric models do not predict these features. In this thesis, a one dimensional photochemical model of the mesosphere has been constructed in order to examine the possibility that these observed effects might originate in this region of the atmosphere. Transport effects are not considered. The model result demonstrates that the observed OH behaviors are not caused by known photochemical reactions in the mesosphere.

Observations of the vertical column abundance of atmospheric
hydroxyl (OH) have been made using a Pepsios (polyetalon
pressure-scanned interferometric optical spectrometer). The
measurements were taken at both Fritz Peak, Colorado (40°N) and Boca
Raton, Florida (26° N) during the period 1985-86. These are high
resolution measurements of the resonance absorption of sunlight by OH in the P1(1) A^2 sigma - x^2 pi (0,0) transition at 3081.66 A. The observations are of relevance to the problem of stratospheric
ozone reduction by man-made pollution. Attempts to model the
photochemistry of the middle atmosphere and to predict its response to
these pollutants depend heavily on an accurate observational data base
of many middle atmospheric constituents. This OH data base contributes
information which is of critical importance to theories describing
middle atmospheric processes.
The author's measurements are discussed within the context of the
ten-year data base accumulated by Dr. Clyde Burnett. Observed
geographic and seasonal regularities, as well as short-period excursions
in the OH abundances, have not been fully explained by current
photochemical theory.

Measurements of the atmospheric hydroxyl radical (OH) abundance
were made at Boca Raton, Florida, (26° 22' N, 80° 6' W)
during the period March 14 through April 9, 1977. Observations
were made on the P1(1) line of the A^2sigma+ - x^2pi(0,0) rotation band of OH at 3081.7A. By the use of the high
resolution Pepsios (poly-etalon pressure scanning interferometric
optical spectrometer) spectrometer, the narrow
absorption curve due to terrestrial OH was distinguished
from the broad solar Fraunhofer line. Measurements of the
amount of atmospheric OH absorption indicated an average
vertical column abundance of (2.0 +- 0.8) (10^13) molecules/cm^2 for this observation period.