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Title: The retrieval of the concentrations of nitric oxide and nitrogen dioxide from satellite solar occultation measurements at sunset and sunrise

Miscellaneous ·
OSTI ID:6100669

HALOE (Halogen Occultation Experiment), scheduled to fly on the Upper Atmosphere Research Satellite (UARS) in 1991, aims to retrieve the vertical concentration profiles of seven minor stratospheric constituents in order to improve the understanding of ozone's photochemistry. This dissertation concentrates on the retrieval of the concentrations of nitric oxide and nitrogen dioxide, which both play an active role in the photochemistry of ozone. The investigation is complicated because of their large diurnal changes which are intensified at sunrise and sunset. Consequently, the retrieval of NO and NO{sub 2} from solar occultation measurements at twilight needs to take into account the lifetimes and the rapid interconversion of NO and NO{sub 2}. If the temporal and spatial variations of NO and NO{sub 2} are neglected, the resulting errors for altitudes less than 20 km reach 100 and 5% respectively and for both sunset and sunrise. A photochemical scheme is developed and a separate code calculates the photodissociation rates of the species involved in photochemical reactions, as a function of latitude, temperature, altitude and season. A retrieval code is developed combining an iterative inversion algorithm, working from top of the atmosphere downwards, and a parameterization of the variability of NO and NO{sub 2}. The method is used to examine the accuracy of the retrieval of the vertical concentration profiles and results show that the recovered profiles are in good agreement with measured ones, reflect the trends of NO and NO{sub 2} at sunset and sunrise and satisfy the accuracy expectations of the HALOE experiment.

Research Organization:
Michigan Univ., Ann Arbor, MI (USA)
OSTI ID:
6100669
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English