We commonly use weather and climate models to predict the atmospheric behavior in the short and long term. These models rely on description of physical processes, especially related to cloud and rain formation, that feedback onto the atmospheric evolution. These descriptions often underly assumptions that we still do not have a complete theory for. Thus, we still struggle to understand prevailing discrepancies in the location of jet streams and storm development. For example, while the development of storms is traditionally thought to reduce the temperature differences in midlatitudes that give rise to storm development, cloud and rain formation within these storms enhances the temperature differences, sometimes even resulting in a net increase. These cycles are most likely associated with clusters of storms with significant socio-economic impact. While the mechanisms by which the lifecycles of storms alter the temperature field must be determined by the warm and cold fronts of the storms, we lack a detailed understanding of the interplay between processes along these fronts and their relation to clusters of storms as well as their climatological intensity and variability. We therefore propose to develop a unifying framework addressing these physical processes across fronts and storms.
Our framework will clarify the mechanisms and the role of frontal lifecycles and storm development in their climatological variability and thereby aid our understanding of biases in weather and climate models. Our framework will also contest our understanding of storm development, as our new theory allows for storms to increase temperature differences. Our new theory will also explain the climatological position, intensity, and variability of storms in terms of processes associated with rain and cloud formation. These findings will also allow us to re-interpret future climate changes predicted by climate models.
There is a dichotomy between theoretical understanding and modelling of weather and climate, where the former mainly assumes a dry atmosphere while the latter relies on parameterizations of physical processes, especially related to moisture and phase changes that can yield a significant feedback on the dynamics. With prevailing model biases in jet streams and storm tracks often being tied to these processes, we thus lack a theoretical underpinning that can aid a physical attribution and alleviation of these biases. For example, while the development of cyclones is traditionally thought to reduce the midlatitude temperature gradient that gives rise to storm development, latent heating within these storms enhances the temperature gradient, sometimes even yielding a net increase. These cycles are most likely associated with events of cyclone clustering with significant socio-economic impact. While the mechanisms by which cyclone lifecycles alter temperature gradients must be determined by frontal dynamics, we lack a detailed understanding of the interplay between processes along fronts and their relation to cyclone clustering as well as storm track intensity and variability. We therefore propose to develop a framework combining moist dynamics across fronts, cyclones, and the storm track.
Our framework will clarify the pertinent mechanisms and the role of frontal lifecycles and cyclone development in storm track variability and thereby aid our understanding of prevailing model biases. It will also contest our understanding of cyclone development, as our new paradigm allows for cyclones to increase temperature gradients. As our new moist storm track model will explain the positioning, intensity, and variability of storm tracks in terms of moist processes, it will allow us to physically attribute model biases and formulate alternative hypotheses about the cause for future shifts of storm tracks.