Resolution of reanalysis data

[trickl]

For many years I have been analysing the origin of air layers in our observations by using the reanalysis and GDAS modes of operation. It is quite obvious that re-analysis yields the better results. In the description, however, I found a rather coarse spatial resolution (more than 3 degrees horizontally) which puzzles me in view of my good results. Can you confirm this low resolution of the re-analysis data field? I need this information for a new paper since I feel that the reviewers will put a question in the regard.

One example included in the paper is attached here for both options. In the upper troposphere there is a moist layer with cirrus clouds, that cannot be explained with the GDAS trajectories for the same initial conditions as the reanalysis run. The reanalysis plot shows low altitudes above the Caribbean Sea as the source region which explains the humidity. The lowest trajectory corresponds to a very dry layer (with ozone peak) of presumable stratospheric origin. The maximum altitude 8 km reached at high latitudes is highly indicative of this.

Looking forward to your reply

Thomas Trickl

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Dr. Thomas Trickl
Karlsruher Institut für Technologie
Institut für Meteorologie und Klimaforschung
Atmosphärische Umweltforschung (IMK-IFU)
Kreuzeckbahnstr. 19
82467 Garmisch-Partenkirchen
Germany

Tel. 0049-8821-183-209
Fax 0049-8821-73573
thomas.trickl@kit.edu
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[ariel.stein]

For GDAS ARL produces a 3 hourly, global, 1 degree latitude longitude dataset on pressure surfaces.

For the reanalysis we produce a 2.5 degree latitude-longitude global grid with output every 6 hours.

For more information about the available meteorological datasets that you can use with HYSPLIT, please visit:
https://www.ready.noaa.gov/archives.php