Extension of global best-track tropical cyclone record using gridded reanalyses

The global best-track dataset provides an ensemble archive of track, intensity, and structure of tropical cyclones (TCs) through primarily the tropical component of the TC lifecycle. Some agencies extend the best-track lifecycle through the dissipation stage, whereas some truncate the best-track when extratropical transition has begun or completed. This heterogeneity has lead to an incomplete TC historical archive regarding the full TC lifecycle, with the post-tropical stage in particular poorly represented. It has also lead to difficulty in quantifying the post-tropical TC threat to Europe, northeast Asia, Alaska, and the northwestern United States given the often truncated best-track.

To alleviate these deficiencies, various newer higher resolution global reanalyses are utilized to extend the track, intensity, and structural historical best-track archive. The gridded reanalyses utilized to this end include ERA40, ERAI, CFSR, and MERRA, with all reanalyses used when possible to produce an ensemble of historical extended tracks. The full track archive is made available for community use.

Analyses of the extended track dataset include: 1) quantification of the continuity (or lack there of) in location, intensity, and structure at the transition point between best-track TC and gridded reanalysis TC; 2) quantification of the threat to higher latitude countries based upon these extended tracks, to complement the existing landfall threat at http://moe.met.fsu.edu/tcprob; 3) quantification of the variance among track, intensity, and structure based upon reanalyses intercomparison for the post-best-track extensions.