Links between moisture and circulation: from the seasonal cycle to climate change

Abstract:

The seasonal cycle exhibits significant changes in circulation and moisture transport. The seasonal changes in moisture transport are driven primarily by changes in circulation. We will describe a theoretical framework, quasi-equilibrium dynamics, which connects rotational and divergent components of the circulation to moist entropy gradients. We will show, using idealized aquaplanet model simulations, that the framework can be used to understand the seasonal tendencies of dynamical moisture transport from spring to summer and summer to fall. Finally, we will discuss how the seasonal tendencies can be used as a modern analogue when interpreting the response of dynamical moisture transport to changes in CO2 in fully coupled climate models.