SHARP Phase II
As described in the Outline, the SHARP research Unit will continue its research along the two leading themes by addressing the key research questions in four scientific projects. As in Phase I, three research issues address relevant aspects of Theme 1 and deal with changes in stratospheric dynamics (with focus on the Brewer-Dobson circulation) and chemical composition (with focus on the evolution of stratospheric O3 and H2O). The fourth research topic will deal with the vertical radiative, chemical and dynamical coupling between stratosphere and troposphere and the impact of stratospheric changes on the troposphere-surface system (Theme 2). Based on new knowledge in the research areas and the outcome of our own research in SHARP-I, the research questions of SHARP-II have been updated or new questions added. In the following, we give a brief update of the state of the art in the four key research areas (Section 3.1), followed by a section describing the innovative research aspects of SHARP Phase II (Section 3.2) and a catalogue of research questions to be studied in SHARP-II.