[Proflist] Joint Center for Satellite Data Assimilation Seminar, February 25th: Krzysztof Wargan

[Ana Carrion - NOAA Affiliate]

*JCSDA Seminar*

*Title*

*The Tropopause Inversion Layer: What Can We Learn from Data Assimilation?*

*Speaker*

*Krzysztof Wargan*

NASA, Global Modeling and Assimilation Office (GMAO)

*Date,  Time & Place*

*February 25, 2015, 2:00pm - 3:00pm*
Conference Center, NOAA Center for Weather and Climate Prediction, 5830
University Research Court, College Park, MD

*Abstract*

The Tropopause Inversion Layer (TIL) is a feature of the extratropical
lower stratosphere characterized by a positive temperature lapse rate
associated with a local maximum of static stability within a shallow layer
directly above the tropopause. Its presence is evident in radiosonde data,
Global Positioning System Radio Occultation measurements and general
circulation models. Radiative and dynamical processes are likely to
contribute to its formation but the mechanisms responsible for the feature
are still being investigated. The importance of the TIL stems from the
implications of near-tropopause static stability patterns for transport of
trace gases and wave propagation.

Older global atmospheric data assimilation systems produced only a weak
TIL, in disagreement with observations. In this talk, we will demonstrate
that the feature is well represented in the Goddard Earth Observing System,
version 5 (GEOS-5) analyses in terms of the season-dependent magnitude,
vertical structure and extent, as permitted by the model resolution but
there is a strong dependence of the analysis TIL on the observing system
used. In particular, the insertion of conventional and hyperspectral
radiance data such as from the Atmospheric Infrared Sounder (AIRS)
instrument yields the most realistic representation of the tropopause
static stability.

In the second part of the talk we will discuss the connections between the
middle atmosphere circulation and the variability of the TIL as seen in
GEOS-5 analyses. We will focus on the impact of sudden stratospheric
warming events on static stability above the wintertime polar tropopause.

*Remote Access*

*Video:** 1. **Go to **JCSDA Seminar* <https://star-nesdis-noaa.webex.com/>
*2. Enter the event number:* *395 844 299*




* 3. Password is JCSDA 4. Click "Join Now". 5. Follow the instructions that
appear on your screen. Audio: USA participants: 1-866-715-2479,  Passcode:
9457557 International:                    1-517-345-5260*

*Contact*

If you would like to present a seminar contact Erin.Jones at noaa.gov

*Seminar Files*

Slides available prior to, and audio recording after, the presentation at
http://www.jcsda.noaa.gov/JCSDASeminars.php

-- 

*Ana Carrion*
National Oceanic and Atmospheric Administration
Program Support Specialist
Riverside (RTi) at NOAA/NESDIS/STAR/JCSDA
NCWCP, E/RA, Room #2652
5830 University Research CT
College Park, MD 20740-3818

Email: Ana.Carrion at noaa.gov
*Main Line**: 301-683-3520*
*JCSDA Front Office: 301-683-3615*
Fax: 301-683-3526
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