[strat_list] Spring AGU (from Natalia Andronova)

[Mark Baldwin]

Dear Colleagues:

         We invite you to  submit an abstract to a Special Session  
A02 at the Spring AGU/Joint Assembly Meeting in Baltimore, Maryland,  
USA, 23-26 May, 2006  entitled  “Role of Atmospheric Water Vapor for  
Climate and Atmospheric Composition"  (A02).

The deadline for the  abstract submission  is 01 March 2006, at 2359UT.

Please visit  http://aoss.engin.umich.edu/events/05-06_events/06- 
JA_NA-JP/   to learn more about the session, invited speakers of the  
session and make an on-line  submission.

Also, you can submit an abstract directly at  http://www.agu.org/ 
meetings/ja06/?content=program.

Please feel free to advertise the session among your colleagues to  
make it more valuable.

A general description of the 2006 Joint Assembly is available at  
http://www.agu.org/meetings/ja06/>http://www.agu.org/meetings/ja06/  .


With the best wishes,

Dr. Natalia Andronova
Department of Atmospheric, Oceanic and Space Sciences
University of Michigan
1541D Space Research Building.
2455 Hayward Street
Ann Arbor, MI 48109-2143
Phone: 734-763-5833
Fax: 734-936-0503
Email: natand at umich.edu

Dr. Joyce Penner
Department of Atmospheric, Oceanic and Space Sciences
University of Michigan
1538 Space Research Building
2455 Hayward
Ann Arbor, MI
Phone: 734-936-0519
Fax: 734-936-0503
Email: penner at umich.edu

Dr. Ben Santer
Program for Climate Model Diagnosis and Intercomparison
Lawrence Livermore National Laboratory
P.O. Box 808, Mail Stop L-103
Livermore, CA 94550, U.S.A.
Phone: 925-422-2486
Fax: 925-422-7675
Email: santer1 at llnl.gov


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Since the early 1970's the study of the middle atmosphere has focused  
on understanding the variability of its chemical and dynamical states  
as driven by both natural and anthropogenic processes. Concurrent  
with these efforts, studies have been carried out to understand both  
short-term and long-term climatic variations that occur both  
naturally and due to the emissions and/or alterations of optically  
active gases by humanity. In these areas of study, stratospheric and  
tropospheric ozone (O3) and water vapor (H2O) have been of particular  
interest, as have the upward trending halocarbons (HC's), nitrous  
oxide (N2O), methane (CH4), carbon dioxide (CO2), and tropospheric  
and stratospheric aerosols, both of natural and anthropogenic origin.  
While some progress has been made in simulating the changing  
atmosphere, a number of observed phenomena remain unexplained, among  
them the reasons for the recently observed trends in upper  
tropospheric/lower stratospheric (UT/LS) water vapor and temperature.
The distribution, variability, and trends of water vapor in the upper  
troposphere and lower stratosphere are important for understanding  
the Earth's climate. Trends in stratospheric water vapor may cause a  
change in the radiative forcing of climate. Water vapor is the  
dominant greenhouse gas in the atmosphere, and can also be a cooling  
agent in the middle and upper troposphere. Despite the stratosphere's  
being relatively dry, small changes in the stratospheric water  
content can substantially alter the stratospheric chemical  
composition and surface climate.
Water vapor is also important for atmospheric chemistry. It is the  
source of the hydroxyl radical, OH, which is extremely important for  
many chemical cycles. Reactive hydrogen oxides (HOX = OH + HO2),  
together with reactive odd nitrogen (NOX = ON + NO2) take part in  
regulating the production and destruction of ozone. The hydroxyl  
radical is important in many aspects of atmospheric chemistry and  
regulates the lifetimes of the longer-lived species such as CH4 in  
the troposphere. Also, water vapor plays an important role in  
atmospheric heterogeneous chemistry, defining aerosol effect on  
climate via formation of the stratospheric clouds.
There are three major questions to be addressed in this session:
         1.      What are the influences of the atmospheric methane  
trends, solar variability, volcanic eruptions and energetic electron  
precipitation (EEP) on the stratospheric water vapor, ozone and  
surface climate?
         2.      Can these factors be responsible for dehydration of  
the equatorial tropopause region and the observed temperature trend  
in the upper troposphere/lower stratosphere?
     3.      Is the stratospheric water budget influenced by the  
observed trends in upper tropospheric water vapor?
This session is expected to scope further understanding the long-term  
changes in climate, and therefore has important practical benefits to  
society.

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