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| Title: |
Impact of Multi-Scale Dynamical Processes and Mixing on the Chemical Composition of the Upper Troposphere and Lower Stratosphere During INTEX-NA
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| Author(s): |
Fairlie, T. Duncan; Avery, Melody A.; Pierce, R. Bradley; Al-Saadi, Jassim; Dibb, Jack; Cohen, Ron; Sachse, Glen
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| Abstract: |
We use high frequency in situ observations made from the DC8 to examine fine-scale tracer structure and correlations observed in the upper troposphere and lower stratosphere during INTEX-NA. Two flights of the NASA DC-8 are compared and contrasted. Chemical data from the DC-8 flight on July 18 shows evidence for interleaving and mixing of polluted and stratospheric air masses in the vicinity of the subtropical jet in the upper troposphere, while on August 2 the DC-8 flew through a polluted upper troposphere and lower stratosphere (middle world) that were more distinctly separated. We compare data from both flights with RAQMS 3-d global meteorological and chemical model fields to establish dynamical context, and to diagnose processes regulating the degree of mixing on each day. We also use trajectory mapping of the model fields to show that filamentary structure due to upstream strain deformation contributes to tracer variability observed in the upper troposphere. Higher frequency (6-24 km) tracer variability is attributed to buoyancy wave oscillations in the vicinity of the jet, whose turbulent dissipation leads to efficient mixing across tracer gradients. A measure of strain and rotation in the large-scale flow, Q, is found useful in predicting filamentary structure in the vicinity of the jet for the cases considered but limited in predicting the higher frequency gravity wave modes.
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| NASA Center: |
Langley Research Center
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| Publication Date: |
August 14, 2006
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| Document Source: |
Other Sources |
| No Digital Version Available: |
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| Document ID: |
20090004465
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| Publication Information: |
Number of Pages = 36 |
| Contract-Grant-Task Number: |
WBS 281945.02.39.01.04 |
| Related Information: |
To be published in Journal of Geophysical Research, volume 112, Aug. 2007 |
| Keywords: |
TROPOSPHERE; STRATOSPHERE; ENVIRONMENTAL TRANSPORT; AIR POLLUTION; ATMOSPHERIC CHEMISTRY; CHEMICAL REACTIONS; CHEMICAL COMPOSITION; ATMOSPHERIC COMPOSITION; ATMOSPHERIC CIRCULATION; EARTH SCIENCES; SPACE LABORATORIES; IN SITU MEASUREMENT; REMOTE SENSING; JET STREAMS (METEOROLOGY); OZONE; CARBON MONOXIDE; NITRIC ACID; NITRATES;
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| Accessibility: |
Unclassified; Copyright; Unlimited; Publicly available; |
| Updated/Added to NTRS: |
2009-01-27 |
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