NASA Langley scientists will report on new atmospheric science discoveries and areas of exploration at the 1999 American Geophysical Union meeting in San Francisco the week of December 13�17, 1999. Details of scheduled papers and poster sessions follow.

Monthly Variations in Atmospheric Air Determined from Langley Satellite Instrument
SAGE II instrument data show a strong seasonal cycle of exchange between tropospheric and stratosphere air. These results agree with previously reported atmospheric model data and aircraft measurements that show the same strong seasonal cycle.
Paper presented by Waldo Rodriguez
Monday, December 13 at 8:30
Moscone Center, Room 309, Session A11D

Water Vapor in the Atmosphere: An Improved Model Possible
Either the UARS Reference Model or SAGE II multi-year satellite observations or their combination could be more useful than the existing US Standard Atmosphere of CIRA model for water vapor.
Paper presented by Er-Woon Chiou
Monday, December 13 at 8:45
Moscone Center, Room 309, Session A11D

Are Aerosol Levels Rising? New Insight Raises Questions Regarding Human Influence
An examination of atmospheric satellite data from three non volcanic-influenced periods, each showing different aerosol concentrations, addresses the question of whether background aerosol levels are rising, and if so, whether this is due to human influence on the stratosphere and upper troposphere.
Invited paper presented by Dr. Larry W. Thomason
Tuesday, December 14 at 2:30
Moscone Center, Room 309, Session A22E

Exploring Why Aerosols Decay Faster in Models than Satellite Observations Indicate
Comparisons of aerosol measurements show them to be in good agreement as to aerosol size before and after volcanic eruptions. Their modeled rate of decay, however, indicates a decay rate faster than that observed by Langley1s SAGE II satellite instrument. Possible explanations are considered.
Paper presented by Dr. Glenn K. Yue
Tuesday, December 14 at 4:35
Moscone Center, Room 309, Session A22E

Observations and Impact of Lightning Nitrogen Oxides in the North Atlantic Upper Troposphere
Highly concentrated plumes of nitrogen oxides observed over the North Atlantic are traced back to regions of intense lightning activity, enabling an examination of their evolution and chemical impact. The transport of these plumes over great distances and their potential importance in sustaining background nitrogen oxides far from source regions represent a challenge for global and regional simulations.
Paper presented by Dr. James H. Crawford
Wednesday, December 15 at 2:35
Moscone Center, Room 307, Session A32F

Measurements Compared for Accurate Depictions of Radiation and Aerosol Radiative Forcing
Comparisons between measured and theoretical estimates of radiative fluctuations and aerosol radiative forcing over oceans are examined to ensure the accuracy of satellite-derived estimates of aerosol radiative forcing.
Paper presented by Norman G. Loeb
Wednesday, December 15 at 4:30
Moscone Center, Room 134, Session A32E I

The Mt. Pinatubo Eruption: Eight Years of Stratospheric Observations
For the first time ever, ground-based, airborne, and spaceborne instruments provided nearly global observations of the initial development and long decay of a volcanic aerosol cloud. This approach produced unique measurements that aided in the understanding of stratospheric aerosol distribution during the 1990's.
Invited paper presented by Dr. Larry W. Thomason
Thursday, December 16 at 1:30
Moscone Center, Room 303, Session A42F

Poster Sessions

Tropical Clouds and Longwave Radiation: Preliminary Results from Satellite Observations
Changes in tropical cloud systems have a profound influence on outgoing radiation. Presented are long-term satellite observations of cloud coverage and longwave radiation, two closely related climate components that enhance the interpretation and understanding of Earth1s climate changes.
Poster presented by Pi-Huan Wang
Monday, December 13 at 1:30
Moscone Center, Hall D, Session A12B

Toward Understanding Uncertainties Affecting SAGE III Data Products
A new computer simulator will model all aspects of the upcoming SAGE III satellite experiment, allowing for the identification of major sources of error and providing insight on the effect of error on the retrieved data products, namely trace gases and aerosol extinction vertical profiles.
Poster presented by Dr. Didier F.G. Rault
Monday, December 13 at 1:30
Moscone Center, Hall D, Session A12B

Atmospheric Temperature Trends Corroborated between Surface and Satellite Measurements
Twelve months of trend agreement between satellite instrument data and surface air temperature data are presented as evidence that Earth Radiation Budget Satellite (ERBS) observations may be used to detect changes in the Earth1s atmosphere system.
Poster presented by Dr. Dhirendra K. Pandey
Monday, December 13 at 1:30
Moscone Center, Hall D, Session A12B

Students On-Line Atmospheric Research Program (SOLAR): Enhancing Science Education
The Student On-Line Atmospheric Research (SOLAR) program, an educational outreach component of NASA's Stratospheric Aerosol and Gas Experiment (SAGE) III program, focuses on developing tutorials and other materials and activities to enhance science education for K-12 students. A Virginia high school pilot program giving students hands-on experience collecting atmospheric data is featured.
Poster presented by David C. Woods
Monday, December 13 at 1:30
Moscone Center, Hall D, Session A12B

Calculations Show Aerosol Extinction Affected by Wavelength
The amount of solar radiation that is scattered and absorbed by atmospheric aerosol particles varies according to their size distribution, chemical composition, and amount. A new technique for determining the size distribution of aerosol particles is explored.
Poster presented by Gregory L. Schuster
Tuesday, December 14 at 8:30
Moscone Center, Hall D, Session A12B

Workshop Enables Teacher Input for Standards Requirements
Elementary, middle, and high school teachers construct NASA1s Students Cloud Observation On-Line (S'COOL) project lesson plans that will enhance Virginia Standards of Learning (SOLs) and national standards.
Poster presented by Carolyn J. Green
Thursday, December 16 at 1:30
Moscone Center, Hall D, Session EP42A

Terra Data Available from the NASA Langley Atmospheric Sciences Data Center
Observations from two new satellite instruments and the newest version of Langley's CERES instrument, all mounted on the EOS Terra satellite, will be available through the Langley Atmospheric Sciences Data Center.
Poster presented by Jamie L. Smedsmo
Thursday, December 16 at 1:30
Moscone Center, Hall D, Session U42A

Observations Reveal Surprising Amount of Ozone Found in Upper Mesosphere: Implications for the Ozone Deficit Problem
A new technique for calculating ozone levels in the mesosphere reveals that measured and modeled amounts of mesospheric ozone are in much better agreement than previously thought.
Poster presented by Dr. Martin G. Mlynczak
Thursday, December 16 at 1:30
Moscone Center, Hall D, Session A42A

The Effects of Smoke from Large Scale Vegetation Fires
Data obtained during two large-scale fires are re-examined using computer modeling, satellite data, and surface observations to trace the distribution of aerosols spreading far from the fires1 origin. Additional analysis will lead to an assessment of the effect of regional fires on surface radiation.
Poster presented by Dr. Paul W. Stackhouse, Jr.
Friday, December 17 at 8:30
Moscone Center, Hall D, Session A51C

Data Sets Available for Stratospheric Aerosol Research
Vertical distribution of aerosol data and aerosol extinction profiles from projects covering the time span of October 1978�April 1999 are available from the NASA Langley Atmospheric Sciences Data Center.
Poster presented by Nancy A. Ritchey
Friday, December 17 at 8:30
Moscone Center, Hall D, Session A51C