Events on Thursday, August 22nd, 2024
- Available Energy and Slow Eigenmodes for Understanding Moisture and Phase Changes in Atmospheric Physics
- Time: 10:00 am - 12:00 pm
- Place: 5280 Chamberlin -
- Speaker: Brad Kumm, Physics Graduate Student
- Abstract: In atmospheric physics, clouds and moisture are some of the greatest challenges. They are the leading source of uncertainty in climate change predictions, and rainfall is arguably the most challenging quantity to predict in weather forecasts. In addition, theoretical understanding of moisture in the atmosphere lags behind the understanding of a dry atmosphere. To increase our theoretical understanding of moisture in the atmosphere this work focuses on two concepts: (i) Energy, and in particular Available Potential Energy (APE), and (ii) slow eigenmodes. The first results presented center around a new decomposition of APE for a compressible, adiabatic atmosphere with phase changes, and shows that it can be decomposed into acoustic and buoyant pieces, which are present in dry decompositions, as well as a new slow "latent" piece which accounts for a parcel changing between saturated, and unsaturated states. Second, a method is presented to account for moisture in a global atmospheric decomposition framework, by splitting it into an Inertio-gravity piece, a Rossby piece, and an additional "slow" piece which accounts for a large fraction of the total atmospheric moisture. Finally, such a decomposition is performed using global moisture data, in what may be the first moist decomposition of this kind, in order to quantify the relative contributions of each of these pieces.
- Host: Samuel Stechmann, Jan Egedal