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| Titel |
The LAGRANTO Lagrangian analysis tool – version 2.0 |
| VerfasserIn |
M. Sprenger, H. Wernli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-13), S.2569-2586 |
| Datensatznummer |
250116506
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| Publikation (Nr.) |
 copernicus.org/gmd-8-2569-2015.pdf |
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| Zusammenfassung |
| Lagrangian trajectories are widely used in the atmospheric
sciences, for instance to identify flow structures in extratropical cyclones
(e.g., warm conveyor belts) and long-range transport pathways of moisture and
trace substances. Here a new version of the Lagrangian analysis tool LAGRANTO
(Wernli and Davies, 1997) is introduced, which offers considerably enhanced
functionalities. Trajectory starting positions can be defined easily and
flexibly based on different geometrical and/or meteorological conditions,
e.g., equidistantly spaced within a prescribed region and on a stack of
pressure (or isentropic) levels. After the computation of the trajectories, a
versatile selection of trajectories is offered based on single or combined
criteria. These criteria are passed to LAGRANTO with a simple command
language (e.g., "GT:PV:2" readily translates into a selection of all
trajectories with potential vorticity, PV, greater than
2 PVU; 1 PVU = 10−6 K m2 kg−1 s−1). Full versions of this
new version of LAGRANTO are available for global ECMWF and regional COSMO
data, and core functionality is provided for the regional WRF and MetUM
models and the global 20th Century Reanalysis data set. The paper first
presents the intuitive application of LAGRANTO for the identification of a
warm conveyor belt in the North Atlantic. A further case study then shows how
LAGRANTO can be used to quasi-operationally diagnose
stratosphere–troposphere exchange events. Whereas these examples rely on the
ECMWF version, the COSMO version and input fields with 7 km horizontal
resolution serve to resolve the rather complex flow structure associated with
orographic blocking due to the Alps, as shown in a third example. A final
example illustrates the tool's application in source–receptor analysis
studies. The new distribution of LAGRANTO is publicly available and includes
auxiliary tools, e.g., to visualize trajectories. A detailed user guide
describes all LAGRANTO capabilities. |
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