Skip Navigation
JCSDA Logo and banner

Attend in Person:

Unless noted otherwise, all seminars take place at:
NOAA Center for Weather and Climate Prediction
5830 University Research Court
College Park, MD  20740

NCWCP building

See Map & Directions from Google

Attend Remotely:

Online video access:

  1. Click on JCSDA Seminars
  2. Enter the event number.
  3. Enter the password: JCSDA.
  4. Click "Join Now".
  5. Follow the instructions that appear on your screen.

Audio / conference call:

USA participants: 1-866-715-2479
Passcode: 9457557
International: 1-517-345-5260


If you are a presenter and are going to be giving a JCSDA seminar with slides, please follow these guidelines on presentation file preparation.

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.
  • Recent seminars are here.

Upcoming Seminars


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

Presentation file posted here when available.

Speaker Krzysztof Wargan
Date Wednesday, February 25, 2015
2:00 p.m. - 3:00 p.m.
Conference Center, NOAA Center for Weather and Climate Prediction,5830 University Research Court, College Park, MD

Show 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
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
International: 1-517-345-5260

Erin Jones

Most seminars are scheduled on Wednesdays at 2:00 p.m. unless noted otherwise. Titles are tentative, and are subject to change.

Modified January 9, 2015 9:01 PM
NOAA | NWS | NASA | Navy Weather
Air Force Weather | Website owner: JCSDA
Level A conformance icon, W3C-WAI Web Content Accessibility Guidelines 1.0 and Valid HTML 4.01 Icon
icon: valid HTML 4.01 transitional. Level A conformance icon, W3C-WAI Web Content Accessibility Guidelines 1.0