[Weather and Climate Seminar Series] - Kathleen Schiro (UVA) - 31 May 2022 3:30 pm CET

[Adrian Tompkins]

*Seminar Announcement*

_May 31 2022  3:30 pm CET_
*
*
*Kathleen Schiro
*/Assistant Professor, Department of Environmental Sciences, University
of Virginia/
http://schiro.evsc.virginia.edu*
* <http://schiro.evsc.virginia.edu>

*"*Impacts of Deep Convection on the Tropical Low Cloud Feedback and
Climate Sensitivity*"*

_Abstract_
Climate model simulations are known to be sensitive to parameter choices
in the sub grid-scale representation of deep convection, as deep
convection plays a critical role in the transport of heat and momentum
globally. Over the years, it has also become evident that the intermodel
spread in the warming response to anthropogenic forcing is largely
driven by uncertainties in the magnitude of the cloud feedback in the
tropics, specifically the low cloud feedback. In this talk, I will
discuss how parameterization differences among models and changes to
deep convection in response to anthropogenic warming are likely
contributing significantly to the intermodel spread in the tropical
cloud feedback. I will present evidence of two physical pathways linking
deep convection to low clouds and their response to anthropogenic
forcing: the "Radiation-Subsidence" Pathway and the "Stability" Pathway.
In a warmer world, the tropical overturning circulation is projected to
weaken. We find that the overturning circulation does not weaken as much
in climate models with more stable tropospheres, which ultimately leads
to a more positive low cloud feedback (Stability Pathway). Differences
in deep convective parameterization modifying deep convection onset
thresholds – such as the fractional rate of entrainment into convective
updrafts – can contribute significantly to this intermodel spread in
static stability. Additionally, changes to the total area occupied by
deep convection in the tropics modify the high cloud fraction, which is
linked to subsidence changes and the low cloud feedback
(Radiation-Subsidence Pathway). Results from both the Coupled Model
Intercomparison Project (CMIP6) and a perturbation physics ensemble in
the Community Earth System model (NCAR CESM) will be presented and
discussed.

_Bio_
Kathleen Schiro is a climate scientist with strong interests in
atmospheric convection, tropical dynamics, and regional
hydroclimatology. The primary goal of her research is to improve our
understanding of clouds, convection, and precipitation in a changing
climate to improve predictability of hydroclimatological changes in
response to anthropogenic warming. Her research combines field campaign
observations, satellite observations, and cloud resolving models to
study the physical processes controlling deep convection and heavy
precipitation at the storm-scale, as well as climate models to study the
interactions between deep convection, clouds, and the large-scale
atmospheric circulation across scales in the tropics. She received a PhD
in Atmospheric and Oceanic Sciences at UCLA in 2017, did a postdoc at
the NASA Jet Propulsion Laboratory from 2018 to 2020, to then move to
the University of Virginia as an Assistant Professor. 

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