Truchelut, R., R. Hart, and B. Luthman, 2013: Global identification of previously undetected pre-satellite era tropical cyclone candidates in NOAA/CIRES 20th Century Reanalysis data. J. Appl. Meteor. Climatol. doi:10.1175/JAMC-D-12-0276.1.
For full documentation and results of the project, please visit: http://moe.met.fsu.edu/tcce/
Prior to the satellite era, limited synoptic observation networks led to an indefinite number of tropical cyclones (TCs) remaining undetected. This period of decreased confidence in the TC climatological record includes the first two-thirds of the 20th Century. While prior studies found this undersampling exists, disagreement regarding its magnitude has caused difficulties in interpreting multi-decadal changes in TC activity.
Previous research also demonstrated that reanalyses can be used to extend TC climatology, utilizing the NOAA/CIRES 20th Century Reanalysis to manually identify previously unknown Atlantic Basin potential TCs. The results significantly expand upon the scope of the earlier work, using a filtering algorithm to identify TC candidate events in all tropical basins for the years 1871-1979. The result is the first quantitative and objective global TC candidate event counts for the decades prior to formal recordkeeping.
Verification using ship reports and other in situ observations performed on a subset of the events indicates that the algorithm identifies potential missing TCs at a success rate of 25%-50%, depending on the basin. As our team has performed the verification process on only a small fraction of the thousands of candidate events identified, maps have been made publically available containing model and observational data produced at 6 hour intervals for each candidate event. These images, as well as full documentation of our research procedures, is provided at the links above. It is our hope that ongoing and future TC climatology revision efforts will use this data as a source of independent guidance in order to produce a more complete record of historical tropical cyclone activity.
We hope you find our work useful, and please do not hesitate to contact us directly with questions or specific data requests.