| This thesis is devoted to an understanding of climate changes in the troposphere and the stratosphere from different aspects. In the troposphere, projecting future climate depends on our understanding of the exchange of CO2 between the atmosphere, oceans, and terrestrial ecosystems. To understand the carbon cycle, it is important to estimate the sources and sinks of CO2. The so-called inverse approach has been widely used to retrieve the abundances of atmospheric species, such as CO2, from global surface networks and subsequently estimate their surface fluxes and variability. Understanding of the global distribution and temporal variability of atmospheric CO2 thus helps constrain the surface carbon sources and sinks. In the stratosphere, the equatorial quansi-biennual oscillation (QBO) affects the polar stratosphere during winter, with the easterly phase of the QBO creating the condition for a more perturbed and warmer polar vortex. Therefore, the variation of the QBO period has additional significance, especially with respect to the timing of its phase relative to the Northern Hemisphere (NH) winter. The study of the interannual variability of the QBO improves our understanding of the climate system.;In this thesis, a retrieval algorithm is developed to estimate both CO 2 column abundance and its profile using radiances in the near-infrared region. In addition, the interannual variability of QBO is explored by studying both observation data and the modeled results. The thesis includes two parts. Part I (chapters 1 and 2) is a summary of the work about the CO2 retrievals. Part II (chapters 3 and 4) is devoted to the stratospheric dynamics. |
