last lecture: "Weather and Climate: From Fundamentals to Applications"

[Adrian Tompkins]

*Join us for the last seminar of the ICTP/UniTN/UniAQ Joint 
International Seminar Series "Weather and Climate: From Fundamentals to 
Applications"*

_Tuesday June 14 2022  3:30 pm CET_
*
*
*Caroline Muller
*/Assistant Professor at the Institute of Science and Technology (ISTA)
Klosterneuburg, Austria /
https://ist.ac.at/en/research/muller-group/*
<http://schiro.evsc.virginia.edu>*

"How Do Ocean Temperature Anomalies Favor or Disfavor the Aggregation of 
Deep Convective Clouds?*"*

_Abstract_
Convective organization at mesoscales (hundreds of kilometres) is 
ubiquitous in the tropics, but the physical processes behind it are 
still poorly understood. Organization can be forced by the large scales, 
such as surface temperature gradients. But convective organization can 
also arise from internal feedbacks, such as "self-aggregation" 
feedbacks. Self-aggregation refers to the spectacular ability of deep 
clouds to spontaneously cluster in space despite spatially homogeneous 
conditions and no large-scale forcing, in high-resolution 
cloud-resolving models (CRMs).Because of the idealized settings in which 
self-aggregation has been studied (typically radiative-convective 
equilibrium (RCE) over homogeneous sea-surface temperature (SST)), its 
relevance to the real tropics is debated. In this presentation, we will 
investigate the impact of removing some of these idealizations on the 
aggregation process. Specifically, we will investigate the impact of 
inhomogeneous SSTs on convective aggregation.

In a first step, we will investigate how an idealized warm circular SST 
anomaly, referred to as "hot-spot", helps organize convection, and how 
self-aggregation feedbacks modulate this organization. The presence of a 
hot-spot significantly accelerates aggregation, particularly for larger 
domains and warmer/larger hot-spots, and extends the range of SSTs for 
which aggregation occurs. In that case, the aggregation onset results 
from a large-scale circulation induced by the hot-spot. In a second 
step, we will investigate the interaction of aggregation with an 
interactive surface (local SST evolving according to the surface energy 
budget). The results will be interpreted in light of a simple model for 
the boundary layer circulation.

_Bio_
Caroline Muller received her PhD from the Courant Institute of 
Mathematical Science at NYU in 2008. She was then a postdoctoral 
researcher at MIT from 2008 to 2010 to then move as a research scholar 
at Princeton/GFDL. In 2012 she moved to France as a CRNS researcher and 
from 2015 she was also a lecturer at the Ecole Normale Superieure in 
Paris. Since 2021, she has been at ITSA as an Assistant Professor. Her 
research interests lie in the fields of geophysical fluid dynamics and 
climate science. She is particularly interested in the study of 
processes which are too small in space and time to be explicitly 
resolved in coarse-resolution General Circulation Models (GCMs) used for 
climate prediction. Important examples of problems she works on are 
internal wave breaking in the ocean and cloud processes in the 
atmosphere. These subgrid-scale processes need to be parametrized in 
GCMs in order to improve current model projections of climate change.

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