PREMIER Report for Mission Selection

The Earth Explorer PREMIER mission will be the first satellite mission to determine 3D fields of atmospheric trace gases and temperature at a resolution high enough to study chemical, dynamic and radiative processes in the upper troposphere and lower stratosphere, the UTLS. Climate is particularly sensitive to atmospheric composition in this region because this is where much infrared radiation escapes to space, where cirrus clouds trap outgoing terrestrial radiation, and where ozone is most effective as a greenhouse gas. In synergy with nadir-viewing operational weather satellites, such as MetOp, PREMIER will also contribute to improved estimates of pyrogenic, biogenic, anthropogenic and volcanic emissions that affect global and regional air quality. State-of-the-art coupled chemistry-climate models provide the best means of predicting future changes in climate on decadal to century time scales. However, for processes occurring on spatial scales smaller than a model's grid size, the models rely on parameterisations of the physical and chemical processes. The current understanding of the interactions between climate change and atmospheric chemistry is subject to large uncertainties, often because of a lack of knowledge about processes at high spatial resolution.

PREMIER will unveil the coupled chemistry and dynamics of the UTLS and provide improved parameterisations for climate-change modelling. The mission's four scientific objectives relate to the impacts of UTLS variability and general atmospheric circulation on Earth's surface climate, the exchange of trace gases between the troposphere and stratosphere, convection and pyroconvection and their impact on the composition of the UTLS, and processes that link the composition of the UTLS and the lower troposphere. The Intergovernmental Panel on Climate Change has identified the interaction between air quality and climate as an area of high priority for future research. This resulted in the establishment of a major joint project on atmospheric chemistry and climate involving the World Climate Research Programme and the International Geosphere Biosphere Programme. PREMIER responds to needs identified in the project and also addresses four (out of five scientific challenges relating to the atmosphere in ESA's Living Planet Programme.