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Audio / conference call:
USA participants: 1-866-715-2479
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Upcoming JCSDA Seminars
About JCSDA's Seminar Series
The JCSDA seminar series includes presentations on satellite observing
instruments, radiative transfer models for use in satellite data
assimilation, algorithms for deriving information on the Earth's
atmosphere, oceans, and land surface from satellite observations,
advances in data assimilation techniques, preparations for
assimilation of data from new satellite instruments, and impacts of
satellite data on weather and climate predictions. The seminars are
about 1 hour in duration (including discussion period) and are held
monthly, usually on the 3rd Wednesday of each month at 2 PM, and are
open to the public.
The audience for the seminars generally consists of remote sensing
researchers from NOAA/NESDIS, data assimilation experts and modelers
from NOAA/NCEP and NASA/Goddard Space Flight Center Global Modeling
and Assimilation Office, and students/faculty from the University of Maryland.
Slides for each presentation should be available for download in PDF
format on this page, the day before each talk.
Unless specifically noted otherwise, the contact for
the JCSDA seminar series is Kevin Garrett.
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.
Video: 1. Go to JCSDA Seminar
2. Enter the event number: 395 844 299
3. Enter the password: JCSDA
4. Follow the instructions that appear on your screen. Presentation slides will also be posted online prior to the presentation. Audio: USA participants: 1-866-715-2479, Passcode: 9457557