Synergy of the Formulation of Atmospheric Convection Parameterization (25rit026)

The Banff International Research Station will host the “Synergy of the Formulation of Atmospheric Convection Parameterization” workshop in Banff from April 23 - May 7, 2025.

One of the major challenges in climate modeling and numerical weather forecasting is rooted in the fact that atmospheric variations occur on a wide range of scales, involving micro-scale processes such as cloud and rain--droplet formation to weather systems occurring on thousands of kilometers and a few days, to climatic phenomena such as the El-Nino Southern Oscillations. Due to limitations in computing resources, climate and weather forecasting models use computer codes that focus on interactive dynamics that occur on scales of a few tens to hundreds of kilometers and physical processes occurring at smaller scales are not captured by the so-called model dynamical core. They are instead indirectly accounted for via simplified mathematical models known as parameterizations. Thunderstorms and the associated processes of precipitation, clouds, and radiative exchange, though they are all extremely important for local as well as global atmospheric dynamics, are all part of the sub-grid scale parameterized physics and fall under the umbrella of the convection parametrization problem. As computers are getting more and more powerful climate and weather forecasting centers are pushing for the use of higher and higher resolution models, and are currently at the intersection of the so-called grey-zone resolution of up to 10 kilometers, where convection flows are partly resolved. This creates a new challenge mainly because the traditional convection parametrizations were designed for coarse grid resolutions. Compounded with the sensitivity of convective flows, clouds, and precipitation variability in general, to global warming, the design of scale-aware convection parametrization that can ensure a smooth transition between resolved and unresolved convective flow regimes is arguably the new grand challenge in climate and weather forecasting modeling. Unfortunately, there is very little rigorous theoretical work that has been done since the inception of the modern convection parameterizations, in the early 70’s-late 90’s. A team of two mathematicians and a physicist will be gathered at BIRS to join efforts to tackle this hard-interdisciplinary problem. They will develop the synergy between stochastic modeling and asymptotic expansion methods, also invoking ideas from non-equilibrium statistical mechanics to come up with a new perspective for the convection parameterization problem. This synergy is expected to lead to new scale and resolution-aware convection schemes to be used in grey-zone resolution climate and weather forecasting models.