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This study evaluates the frequency, distribution, and evolution of tropopause folding and its impact on stratosphere-troposphere ozone exchange during the TOPSE campaign using GOES derived product images.
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Evaluation of Stratosphere-Troposphere Ozone Exchange During TOPSE Using GOES Derived Product Images A. J. Wimmers, J. L. Moody Department of Environmental Sciences, University of Virginia E. V. Browell, J. W. Hair, C. F. Butler, W. B. Grant, M. A. Fenn NASA Langley Research Center, Lidar Applications Group C. C. Schmidt, J. Li Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin - Madison
Thule Churchill Winnipeg Boulder • TOPSE: Tropospheric Ozone • Production About the SpringEquinox • Feb 4 - May 23, 2000 • Consisted of transects between ~ 40 - 80 deg N • Included both in-situ measurements and upward, downward Lidar
Research questions: • What was the frequency of the tropopause folding/STE over the domain of TOPSE? • How (if at all) did that frequency change over the February-May period? • What was the distribution and evolution of tropopause folding over the domain of TOPSE? • How does tropopause folding deliver stratospheric ozone into the troposphere? • How does this flux change in character and in magnitude over the spring?
The Altered Water Vapor Product (AWV) • Is an adjustment to the images of the Water Vapor channel of the GOES satellite • Gives a more accurate depiction of moisture amounts in the mid-to-upper troposphere over nearly the full spatial scale of the image domain • Consequently, we can observe large, global-scale advections near the tropopause height • 10-km resolution is better than models or any measurement network • Since stratospheric air is very dry, the advection and mixing of stratospheric air are apparent as the advection and destruction of features of low moisture • This project is the first combined application of satellite imagery of this kind and lidar soundings
Case 1: Equatorward advection of stratospheric air Flight 42 - May 23 00:00 UTC
Case 1: Equatorward advection of stratospheric air Flight 42 - May 23 06:00 UTC
Case 1: Equatorward advection of stratospheric air Flight 42 - May 23 12:00 UTC
Case 1: Equatorward advection of stratospheric air Flight 42 - May 23 18:00 UTC
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19:30 UTC Case 2: Along-fold transect Flight 36, April 30
21:45 UTC Case 2: Along-fold transect Flight 36, April 30
Case 2: Ozone transport between cyclones 102 hours before the flight
Case 2: Ozone transport between cyclones 78 hours before the flight
Case 2: Ozone transport between cyclones 66 hours before the flight
Case 2: Ozone transport between cyclones 42 hours before the flight
Case 2: Ozone transport between cyclones 30 hours before the flight
Case 2: Ozone transport between cyclones 6 hours before the flight
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034
Streamer fragmentation and tropopause folding in the GOES viewing domain “Major Folding Interface” JD 034
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 065
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 065
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 086
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 086
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 122
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 122
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 144
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 144
JD 065 JD 034 JD 086 JD 122 Springtime trends in streamer evolution and fragmentation, 2000 JD 144
The contraction of the “Major Folding Interface” • This is important because if we assume that the flux across the tropopause throughout the globe is proportional to the length of the “major folding interface,” then the seasonality of STE can be observed through the change in the length of this interface. • The contraction of this interface in mid-May implies that the most active cross-tropopause transport that we observe overlaps in time with the spring bloom of ozone in the troposphere. This is possible evidence that STE makes a significant contribution to the ozone bloom. • However, since this whole idea rests on an unsupported assumption (that the total STE is proportional to the length of the folding interface) it is more of a working hypothesis than a solid theory. Nevertheless, it should be a good launching point for more discussions on STE.
Summary/Conclusions Summary/Conclusions • What was the distribution and evolution of tropopause folding over the domain of TOPSE? - Tropopause folding can have a length of several hundred kilometers, creating a large interface where mixing between the stratosphere and troposphere is possible.
Summary/Conclusions • What was the distribution and evolution of tropopause folding over the domain of TOPSE? - Previous events of strat-trop exchange (STE) often advect and develop into the next event of STE. This ought to complicate the measurement of “new” ozone observed in a single transect.
Summary/Conclusions • What was the distribution and evolution of tropopause folding over the domain of TOPSE? - Decreased meridional transport contracts the “major folding interface” during late spring. This is a direct indication of how STE contributes to the springtime bloom of ozone in the troposphere. JD 122 JD 144
Research questions (reprise): • What was the distribution and evolution of tropopause folding over the domain of TOPSE? • How does tropopause folding deliver stratospheric ozone into the troposphere? • How does this flux change in character and in magnitude over the spring?
Acknowledgements • TOPSE colleagues • SSEC/CIMSS - GOES Total Ozone data
WV AWV