Please note this seminar will be in BLKT 1004.

Professor Trude Storelvmo will be joining us next Tuesday, 23 April, to give a seminar on their work on the cloud phase feedback.

The cloud phase feedback and its dependence on cloud regime and climate state

The ways in which clouds change with global warming remain elusive, as are the associated cloud-climate feedbacks that govern most of the spread in climate sensitivity simulated by current Earth System Models. Despite considerable research progress in recent decades, additional complexities have been uncovered that further add to the uncertainty. An example is the understanding that many cloud-climate feedbacks change with time, due to their dependence on warming levels or patterns. Cloud thermodynamic phase changes are the root cause of some of this state-dependence, and our findings reveal that these feedbacks could shift Earth’s climate into a state that is more sensitive to greenhouse gas forcing than at present. Understanding and quantifying this state-dependence is therefore critically important, but requires deep understanding of processes on a range of scales, from the microphysics that control cloud phase to large-scale impacts on climate.  It has also become evident that different cloud regimes are governed by different processes with their own unique state-dependence that must be investigated separately. Here, we present new research findings that contribute to the understanding  and quantification of feedbacks associated with cloud phase changes, including their state-dependence and implication for estimates of climate sensitivity. We focus on two distinct cloud regimes, in the Arctic and the Southern Hemisphere storm tracks. The findings are the results of a combination of aircraft measurements, lab experiments, space-borne remote sensing, and a hierarchy of numerical model simulations.