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<p>Colleagues, <br>
</p>
<p>The date and time of the seminar for the 4th EOAS MET faculty
candidate has changed to Thursday March 9th at 3:15 in EOAS 1044.
For those that can't be there in person, the zoom link is</p>
<p><a class="moz-txt-link-freetext" href="https://fsu.zoom.us/j/95826615551?pwd=Tk1LQ0Q5UEN1MEVqbDRCc1BkVi9KUT09">https://fsu.zoom.us/j/95826615551?pwd=Tk1LQ0Q5UEN1MEVqbDRCc1BkVi9KUT09</a></p>
<p>Speaker: Troy Zaremba <br>
</p>
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<p style="margin: 0px; font-variant-numeric: normal;
font-variant-east-asian: normal; font-stretch: normal;
font-size: 13px; line-height: normal;">Title: Precipitation
Growth Processes in the Comma Head Region of the 7 February 2020
Northeast Snowstorm: Results from IMPACTS</p>
<p style="margin: 0px; font-variant-numeric: normal;
font-variant-east-asian: normal; font-stretch: normal;
font-size: 13px; line-height: normal; min-height: 15px;"><br>
</p>
<p style="margin: 0px; font-variant-numeric: normal;
font-variant-east-asian: normal; font-stretch: normal;
font-size: 13px; line-height: normal;">Abstract: On 7 February
2020, precipitation within the comma head region of an
extratropical cyclone was sampled remotely and in-situ by two
research aircraft during the Investigation of Microphysics and
Precipitation for Atlantic Coast-Threatening Snowstorms
(IMPACTS) field campaign, providing a vertical cross-section of
microphysical observations and fine-scale radar measurements.
The sampled region was stratified vertically by distinct
temperature layers and horizontally into a stratiform region on
the west side, and a region of elevated convection on the east
side. In the stratiform region, precipitation formed near cloud
top as polycrystalline crystals. No supercooled water was
present. Polycrystalline habits occurred through the cloud
depth, implying that the cloud top region was the primary source
of particles. Total number concentration slightly decreased with
depth, consistent with growth by vapor deposition and
aggregation. In the convective region, new particle habits were
observed within each temperature-defined layer along with
detectable amounts of supercooled water, implying that ice
particle formation occurred in several layers. Total number
concentration decreased from cloud top to the -8°C level,
consistent with particle aggregation. At temperatures >-8°C,
ice particle concentrations in some regions increased to >100
L-1, suggesting secondary ice production occurred at lower
altitudes. Recent work also shows that cloud top phase was
predominantly liquid within the convective region and
predominantly ice within the stratiform region. WSR-88D
reflectivity composites during the sampling period showed a
weak, loosely organized banded feature. The increase in
reflectivity associated with the easternmost band was consistent
with the melting ice particles. A conceptual model of
precipitation growth processes within the comma head will be
presented. <br>
</p>
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<p>Regards,<br>
Mark<br>
</p>
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