7TROPICAL Reanalysis of the 1970s Atlantic Hurricane Database - Re-discovering "Missing" Tropical Storms and Hurricanes

The Atlantic Hurricane Reanalysis Project is an ongoing project at NOAA to correct systematic biases and random errors in the official Atlantic Hurricane Database (HURDAT2). This database contains the positions and intensities of every tropical cyclone in the Atlantic basin every six hours, from 1851 to present. It is critical that the database is as accurate and complete as possible since the database is heavily utilized and relied upon by insurance companies setting rates for homeowners’ insurance, engineers and lawmakers setting standards for building codes, researchers for conducting climate change studies, and forecasters at the National Hurricane Center who use forecasting tools that are based on the climatological record. This presentation provides an overview of the project, which has thus far added 35 years to the database (1851-1885) and officially revised 85 seasons (1886-1970). In particular, the major changes to genesis, track, intensity (maximum winds), and dissipation for systems in the database will be highlighted . Of particular interest is the opportunity to add newly re-discovered “missing” tropical storms and hurricanes. These newly added systems, while not contributing much toward overall activity (as measured, for example, by Accumulated Cyclone Energy), do significantly increase the frequency of tropical storms in the database. Implications for studies of long-term climate variability and change of these systems are emphasized.