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| Titel |
Combining airborne gas and aerosol measurements with HYSPLIT: a visualization tool for simultaneous evaluation of air mass history and back trajectory consistency |
| VerfasserIn |
S. Freitag, A. D. Clarke, S. G. Howell, V. N. Kapustin, T. Campos, V. L. Brekhovskikh, J. Zhou |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 1 ; Nr. 7, no. 1 (2014-01-14), S.107-128 |
| Datensatznummer |
250115560
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| Publikation (Nr.) |
 copernicus.org/amt-7-107-2014.pdf |
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| Zusammenfassung |
The history of air masses is often investigated using backward trajectories
to gain knowledge about processes along the air parcel path as well as
possible source regions. Here, we describe a refined approach that
incorporates airborne gas, aerosol, and environmental data into back
trajectories and show how this technique allows for simultaneous evaluation
of air mass history and back trajectory reliability without the need to
calculate trajectory errors.
We use the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT)
model and add a simple semi-automated computing routine to facilitate
high-frequency coverage of back trajectories initiated along free
tropospheric (FT) flight tracks and profiles every 10 s. We integrate our in
situ physiochemical data by color-coding each of these trajectories with its
corresponding in situ tracer values measured at the back trajectory start
points along the flight path. The unique color for each trajectory aids
assessment of trajectory reliability through the visual clustering of air
mass pathways of similar coloration.
Moreover, marked changes in trajectories associated with marked changes evident
in measured physiochemical or thermodynamic properties of an air mass add credence
to trajectories. This is particularly true when these air mass properties are
linked to trajectory features characteristic of recognized sources or processes.
This visual clustering of air mass pathways is of particular value for large-scale 3-D flight tracks
common to aircraft experiments where air mass features of interest are often
spatially distributed and temporally separated.
The cluster-visualization tool used here reveals that most FT back
trajectories with pollution signatures measured in the central equatorial
Pacific reach back to sources on the South American continent over
10 000 km away and 12 days back in time, e.g., the Amazonian basin. We also
demonstrate the distinctions in air mass properties between these and
trajectories that penetrate deep convection in the Inter-Tropical Convergence
Zone. Additionally, for the first time we show consistency of modeled
precipitation along back trajectories with scavenging signatures in the
aerosol measured for these trajectories. |
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