The interpretation of SAGE II ozone measurements in the lower mesosphere

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5938277

Chu, D C.A.

SAGE II observations of ozone at sunrise and sunset (solar zenith angle=90{degree}) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 km and 65 km altitude. Because of rapid conversion of atomic oxygen to ozone at sunset and the reverse at sunrise, the onion peeling assumption of constant ozone in the SAGE II retrievals is invalid in this altitude range. The observations are compared against predictions from a one-dimensional model by deriving simulated ozone profiles obtained by applying the onion peel procedure to model results. Good agreement between the observed and modeled sunrise/sunset ratios is then obtained. The results indicate that the SAGE II ozone retrievals overestimate by a factor of 1.3 at sunrise and 1.1 at sunset at 65 km (for example). Between 55 and 60 km altitude the Chapman reactions produce an adequate simulation of the sunrise and sunset ratio, but between 60 and 65 km this ratio is affected by the destruction of O{sub x} by HO{sub x} during the first part of the night. SAGE II ozone profiles between 60 and 65 km altitude thus provide information on mesospheric HO{sub x} chemistry not only through profiles averages but also through the sunrise/sunset ratio. The observations, for example, indicate an OH concentration at 65 km altitude in the tropics an hour after dark of approximately 8x10{sup 6} cm{sup {minus}3}.

• Research Organization: Georgia State Univ., Atlanta, GA (USA)
• OSTI ID: 5938277
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CHEMISTRY
CHEMICAL COMPOSITION
CHEMISTRY
COMPARATIVE EVALUATIONS
DAILY VARIATIONS
EARTH ATMOSPHERE
ELEMENTS
GEOGRAPHICAL VARIATIONS
HYDROGEN COMPOUNDS
HYDROXIDES
LATITUDE EFFECT
MESOSPHERE
MONITORING
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
OZONE
QUANTITY RATIO
VARIATIONS