HR: 1340h
AN: A23B-0952    [Abstracts]
TI: Analysis of Interannual Variability in Stratospheric Ozone as seen by SAGE II, HALOE, SBUV(/2) and Ozonesondes, and Implications for Ozone Trends.
AU: * Terao, Y
EM: yterao@fas.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 United States
AU: Logan, J A
EM: jal@io.as.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 United States
AB: Quantitative assessment of differences in stratospheric ozone trends observed by several instruments is crucial to improve our understanding of trend uncertainties. We compared time series of monthly mean ozone obtained by the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Halogen Occultation Experiment(HALOE), the Solar Backscatter UltraViolet (SBUV) instruments, and ozonesonde data in northern mid-latitudes. The results of comparisons of ozone anomalies for SAGE II, HALOE and ozonesondes show that the differences between SAGE II/HALOE and ozonesondes are ± 6 % at 50 hPa and ± 20 % at 125 hPa, and these have seasonal variations. To explore causes of the SAGE-sonde differences, we used the SBUV(/2) measurements that coincided with ozonesonde or SAGE II measurements: Any differences between the SAGE-sampled SBUV data and the sonde-sampled SBUV data are caused by differences in sampling. The results show that a large fraction of the SAGE-sonde differences is caused by spatial/temporal sampling only (up to 0.86 at 50 hPa). We also discuss the biases of four SBUV(/2) sensors on board Nimbus 7, NOAA 9, NOAA 11, and NOAA 16 with respect to the SAGE II and ozonesonde measurements. We find significant differences in ozone trends derived from ozonesonde and SAGE II, and that the differences in trends are mostly caused by differences in sampling. To investigate whether the sampling issue affects zonal mean ozone trends, we analyzed trends for SAGE II and SBUV(/2) from 60° S to 60° N with 10° bins. The SAGE-sampled SBUV trends are quite different from the SAGE II trends, and the SAGE-sampled SBUV trends are almost same as the SBUV trends that include all SBUV(/2) data. This indicates that the sparse sampling of SAGE II compared with SBUV(/2) does not affect zonal mean trends. Differences in data quality between SAGE II and SBUV(/2) cause the differences in ozone trends derived from these data sets.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005