Storm track intensity and midlatitude cloud feedback

Cloud-radiative feedbacks remain a major stumbling block in understanding and quantifying climate sensitivity. Recent assessments show that the tropics and midlatitudes contribute roughly equally to the global cloud feedback.

Despite its importance, midlatitude cloud feedback has received relatively little attention, and there is still no accepted explanation for why it is positive or what mechanisms determine its magnitude.Here, we propose and test a theory for midlatitude cloud feedback. The theory focuses on cloud-circulation coupling the midlatitude storm tracks.

It builds on recent work by the PI and collaborators showing that cloud amount in the storm tracks depends on the intensity of storm activity, which in turn depends on the equator-to-pole temperature gradient.

As the climate wams, this gradient relaxes, yielding reduced storm track intensity, reduced cloudiness, and positive cloud-radiative feedback.We will test this theory using a combination of observational studies and climate model experiments. The project will last 4-years and will be carried out by the PI and a PhD student to be recruited.

We aim to explore a broad range of warm and cold climates, making the results relevant to paleoclimates and to Earth´s long-term future.

The project innovates by combining insights from large-scale atmospheric dynamics with progress made in understanding local-scale cloud processes, two strands of research that have often remained separate.