GMD Seminars
For questions about GMD seminars, contact Irina Petropavlovskikh, Phone: (303) 497-6279 or Ann Thorne, Phone: (303) 497-4600. Visitors from outside the NOAA campus need to contact Irina or Ann at least one day before the seminar date to be added to the visitor's list at the security gate.

*NEW Additional Requirement for Visitors:* Names of all off-site visitors without a U.S. government issued ID badge must be collected and submitted to security in advance of every seminar. Please call Ann Thorne at 303-497-4600 (leave a message including your name) or send an e-mail to Irina Petropavlovskikh by the day before the seminar if you plan to attend.

Speaker: Henry (Rennie) B. Selkirk, Bay Area Environmental Research Institute, Sonoma, CA 95476 USA
Date/Time: Thursday, August 21, 2008, 3:30 pm
Location: Multi-purpose Room (GC-402) David Skaggs Research Center (DSRC)
NOAA Building - DOC Boulder Campus
Title: Coupling of tropopause dehydration and intrusion of middle latitude air into the tropical lower stratosphere over Costa Rica during Ticosonde-Aura/TCSP, July 2005.

ABSTRACT
I will report on the unusual attributes of one of the water vapor and ozone balloonsonde profile pairs obtained over Costa Rica during the July 2005 Ticosonde/Aura-TCSP campaign. This sounding, launched on July 19 at 18 UT, captured a brief period in that boreal summer in which the upper troposphere over the American Tropics was filled with slowly-ascending, low-ozone air injected by the powerful Hurricane Emily, then passing through the central Caribbean. At this same time air parcels of mid-latitude origin were provided a conduit into the deep tropics in the northeasterly lower stratospheric flow in the wake of the hurricane. I will show how these phemomena were linked by a regular 4- 5 day period equatorial wave that induced large-cooling and equatorward flow as it moved westward through the Caribbean and in combination with Hurricane Emily produced unusually strong cold anomalies of tropopause temperature and northeasterly flow over the region. To provide context for this event, the talk will begin with a review of the four boreal summer Ticosonde campaigns in Costa Rica that have taken place since 2004. In each of these summers synoptic-scale equatorial waves -- undoubtedly driven by convection in the region -- are a regular feature in the lower stratosphere and upper troposphere, and are the single largest contribution to the variability of tropopuase temperatures. Since 2005 we have taken numerous profiles of water vapor and ozone in the UT/LS with the University of Colorado/NOAA Cryogenic Frostpoint Hygrometer and the ECC ozonesonde respectively. On certain occasions we have observed that the wave-induced cooling drives dehydration of tropopause layer air down to water vapor levels more commonly associated with the western Pacific region in boreal winter. In the present instance, we show through convective influence trajectory analysis that the presence of a hurricane in the region served to amplify the effects of the wave, and what resulted in the upper tropopause was deep, slowing ascending tropopause layer that became dehydrated at the tropopause to under 3 ppmv, while in the stratosphere immediately above laminae of middle latitude air shed from the hemispheric-scale monsoon flow were finding entry into the tropics. These observations suggest that in high amplitude situations, wave-induced horizontal transport in the tropical upper troposphere and lower stratosphere can both erase the background vertical tracer gradients typical in the tropical tropopause layer as well as transport middle latitude air deep into the tropics.

Speaker: Dr. Christopher Barnet, Integrated Observing System Science and Product Development Team (IOSSPDT) NOAA/NESDIS/STAR, Camp Springs, MD
Date/Time: Thursday, September 11, 3:30 pm
Location: Multi-purpose Room (GC-402) David Skaggs Research Center (DSRC)
NOAA Building - DOC Boulder Campus
Title: Deriving atmospheric trace gas products from hyperspectral sounders.

ABSTRACT
Operational hyperspectral thermal sounders, designed for retrieving high accuracy global atmospheric temperature, moisture, and cloud products for weather and climate applications, are also capable of retrieval of trace gases. At NOAA/NESDIS we have been exploring the use of these instruments for the retrieval of ozone, carbon monoxide, methane, carbon dioxide, nitric acid, and nitrous oxide. The Atmospheric Infrared Sounder (AIRS), launched on the NASA Aqua platform in 2002, has been used to characterize these products and an assessment of the current capabilities will be discussed in the context of AIRS and other existing and planned satellite assets. This presentation will focus on the advantages and limitations of thermal sounders and will encourage discussion on the potential utility of these long-term, global, multi-gas datasets in climate and carbon-cycle applications.