New Paper on easterly waves and moist convection

A new paper (With James Russell and Dylan White) on easterly waves and moist convection has been published in the Journal of Advances in Modeling Earth Systems.

African Easterly Wave Dynamics in Convection Permitting Simulations: Rotational Stratiform Instability as a Conceptual Model. With J. Russell and D. White.

In this paper, we examine how clusters of precipitating convection within the envelope of synoptic scale easterly waves over Africa can help maintain the latter. We use a numerical weather forecasting model that can represent important features of these mesoscale convective cloud clusters. We connect the results of our simulations to prior studies of equatorial/tropical wave instabilities and ideas of balanced dynamics. The interaction between the parent wave and the upscale effect of moist convection is viewed from the perspective of potential vorticity (PV) budget. The key finding is that the production of PV by the diabatic heating associated with large swaths of stratiform rainfall reinforces the existing PV within the wave. To the extent that easterly waves exist within the regime of balanced dynamics, there is an implicit connection between their PV and the wind/thermal structures. Thus when precipitating convection enhances the wave-scale PV, it in essence also enhances the wind and thermal perturbations. This can in turn precondition the atmosphere for subsequent moist convection, thus closing the loop for the feedback and instability

Key papers relevant to this study (we build on ideas from these previous studies)

Raymond, D., Fuchs, Z., Gjorgjievska, S., & Sessions, S. (2015). Balanced dynamics and convection in the tropical troposphere.J. Adv. Mod. Earth Sys., 7(3), 1093–7031116

Mapes, B. E.(2000).Convective inhibition, subgrid-scale triggering energy, and stratiform instability in a toy tropical wave model. J. Atmos. Sci., 57(10), 1515–6731535.674

Mapes, B. E., Tulich, S., Lin, J., & Zuidema, P. (2006). The mesoscale convection life cycle: Building block or prototype for large-scale tropical waves? Dynamics of atmospheres and oceans,42(1-4), 3–29.

Adames, A. F., & Ming, Y.(2018).Interactions between Water Vapor and Potential Vorticity in Synoptic-Scale Monsoonal Disturbances: Moisture Vortex Instability. J. Atmos. Sci., 75(6), 2083-2106.