This session will focus on recent observational results, as they relate to global trends and variability in the stratospheric indicators of climate change e.g., well-mixed greenhouse gases, water vapor, ozone, aerosols, and temperature and dynamical activity. Topics will include quality of data, time series and sampling problems, uncertainties in observations, effects of uncertainties on trend estimates, intercomparison of data, methods of trends determination, spatial distribution of trends etc.

Keckhut: Temperature trends in the stratosphere and mesosphere: Tidal inferences (O/2.8)

H. Miller: The transition from SSU to AMSU data in CPC stratospheric analyses (O/2.9 bis)

L. Goldfarb: A climatological study of cirrus clouds measured by lidar at OHP (O/2.11)

D. Gaffen: Climatological characteristics of the tropical tropopause as revealed by radiosondes (O/2.12)

L. Hood: The solar component of long-term statospheric variability : observations, model comparisons, and possible mechanisms (O/2.14)

Subsession 2-1: Observational Platforms and Measurements

U. Cortesi: The APE-GAIA campaign: Airborne Polar Experiment - Geophysica Aircraft in Antarctica (P/2-1.3)

E. Oriol-Pibernat: Status of the METOP-1 Program at ESA (P/2-1.4)

C. Rafanelli: The Brewer ozone sampling in Ushuaia and Belgrano II (P/2-1.9)

J. Wickert: GPS radio occultation with CHAMP (P/2-1.12)

Subsession 2-2: Changes in Species (non-ozone)

B. Gonzalez: Observations of cirrus clouds with lidar in Camaguey: Statistical analysis and their relationship with the tropical tropopause (P/2-2.3)

Subsession 2-3: Changes in Ozone

R. Piacentini: Intercomparision between ground based and TOMS/EP satellite southern hemisphere ozone data. New results (P/2-3.2)

J. Karhu: Ozone over Marambio (64°23’S, 56°72’W), Antarctica during 1987-1999 (P/2-3.3)

A. Pazmino: Study of the Antarctic ozone depletion over Marambio (P/2-3.5)

O. Zyryanova: The regional variations of total ozone and tropospheric ozone in the south of Kazakhstan (P/2-3.10)

A. Sarkissian: Trends in total ozone measured by SAOZ network at polar circles, mid-latitudes and tropics (P/2-3.12)

A. Meier: Observation of trace gases from Australia (34°S) by means of ground-based solar FTIR spectroscopy, part 2:Isotopic signals in O3, H2O, and N2O (P/2-3.14)

A. Torres Contador: Study of the instability of the ozone Antarctic hole and their consequences in the South Cone of America (P/2-3.15)

Subsession 2-4: Changes in Temperature

S. Sherwood: Trends and variability in upper troposphere / lower stratosphere temperatures (P/2-4.4)

C. Cagnazzo: Seasonal and interannual variability of stratospheric temperatures based on TOVS satellite data: 1987-1995 (P/2-4.5)

Subsession 2-5: Data Analysis and Model Studies

N. Muthama: Total ozone as a stratospheric indicator of climate variability and change over an African tropical region (P/2-5.2)

M. Yela: Seasonal evolution of NO2 and O3 outside, at the edge, and inside the Antarctic polar vortex: Comparisons with the SLIMCAT model (P/2-5.6)

N. Andronova: Study of the relationship between interannual climate variability and the interannual variability of ozone and methane (P/2-5.8)

T. Halenka: Long term global stratospheric circulation analysis by spectral expansions (P/2-5.10)

G. Braathen: Polar vortex climatology from the ECMWF ERA-15 data set (P/2-5.11)

L. Da Silva Matus: Analysis of the Atmospheric Dynamic during the Depletion of the Ozone Column over the West Coast of South America (P/2-5.12)