Three-dimensional ozone distribution based on assimilation of nadir-sounding UV-VIS satellite observations

Ozone (O3) directly and indirectly affects human health (depending on the altitude it is sometimes referred to as “good” or “bad” ozone) and has an important role in the temperature structure of the atmosphere. Because of the impact of ozone on air quality and climate change, the objective of this thesis is to improve our understanding of the global distribution of atmospheric ozone in space and time, not just in the stratosphere, but also in the troposphere, where it directly affects living organisms.
In this thesis, ozone is measured with satellite-based instruments that measure reflected solar light in the Ultra Violet - VISible (UV-VIS) wavelength range (280 < λ< 330 nm). In the UV-VIS, the absorption crosss-ection of ozone varies by several orders of magnitude, providing the altitude information for the ozone distribution. The ozone profiles are retrieved from the measured radiation with the optimal estimation technique. To make optimal use of the advantages of both observations and atmospheric models, they are combined using the Kalman filter data assimilation technique.The assimilation output consists of regular gridded 3D ozone fields without missing data at regular time intervals.