Summary

Our research focuses on understanding how atmospheric water conditions the behavior of the climate system. This leads to efforts to answer specific questions such as how cloud processes set the planetary albedo, how moist processes influence the structure of the troposphere, and how `water-powered' circulation systems interact with the surface and the stratosphere. Over the past few years these efforts have led to new developments, in both our modeling and in our measurement capabilities - developments that are resonating in ways that are new, not just for us and the questions we pose, but for the field as a whole.

The new developments in the modelling have the form of a critical transition. It is now possible to perform very large-domain, and even global, storm-resolving (kilometer-scale) simulations on time scales that are important for the coupling between moist processes and the climate system. Our year-long storm-resolving (5 kilometer) coupled simulations are the first of their kind, as were the global atmospheric simulations performed in the context of the DYAMOND project which we led. This capability has been transformative in that it allows us to now study moist processes from the point of view of the atmospheric general circulation and the climate system as a whole; it reduces the scope of poorly constrained model assumptions (in the form or parameterizations of microphysics and turbulence); and it works in terms of observables, thereby linking more naturally to observations. For the questions that interest us, these qualities result in better posed problems with increased bandwidth to the broader scientific community. Complementing this critical transition in the modelling has been the development of new experimental methods as employed in the EUREC⁴A campaign, and the maturing observational capability of the Barbados Cloud Observatory, which together allow us to measure how water, in the form of clouds or other moist processes, link to circulation.