HURRICANE TRACK DATA ARCHIVE

Our current understanding of gustiness in hurricane conditions suggests a boost of 1.06 to convert from a 5-min to a 1-min maximum wind ( Powell et al. Weather Bureau reports of вЂњmaximum windsвЂќ during this era, due to instrumental uncertainties in obtaining shorter time period winds.) With the availability of reliable calibrations beginning in the 1920s, the true velocity of this observation was determined to be only about 77 kt. (A standard of 5 min was typically utilized in U.S. Weather Bureau station in Miami, Florida. One of the strongest observed winds in an Atlantic hurricane by this type of anemometer was a 5-min peak wind measurement of 100 kt in storm 7 during 1926 (вЂњthe great Miami hurricaneвЂќ) at the U.S. Moreover, most of these early four-cup anemometers were disabled or destroyed by the TC before sampling the highest winds. For example, when these instruments indicated winds of minimal hurricane force of 64 kt, the true wind was only 50 kt. These showed that the winds from the early cup anemometers had a strong overestimation bias, which was most pronounced at hurricane-force wind speeds ( Fergusson and Covert 1924 Kadel 1926). By the early 1920s, wind tunnels allowed for calibration against much stronger winds.

Even as late as the 1890s, the highest wind that could be reliably calibrated with this instrument was only about 30 kt (from a whirling machine-similar in structure to a record player), due to a lack of reliable comparisons with a known quantity of faster motion. Its primary limitations were in calibrating the instrument and its mechanical failure in hurricane-force wind conditions. The original four-cup anemometer, first developed by Robinson in the 1840s ( Kinsman 1969), was still widely used in the United States until the 1920s and in other countries in the region for some time after that. The one significant change was with regard to the type of anemometer utilized in U.S.-based observing sites. The limited observational capabilities of the 1920s were quite similar to that of the previous few decades: measurements from unfortunately placed ships at sea and from coastal weather stations ( Landsea et al. Highlights are given for changes to the more significant hurricanes to impact the United States, Central America, and the Caribbean for this decade. Average uncertainty in intensity and track values is estimated for both open-ocean conditions as well as landfalling systems. The 1921вЂ“30 dataset now includes several new tropical cyclones, excludes one system previously considered a tropical storm, makes generally large alterations in the intensity estimates of most tropical cyclones (both toward stronger and weaker intensities), and typically adjusts existing tracks with minor corrections. The methodology for the reanalysis process for revising the track and intensity of tropical cyclone data has been detailed in a previous paper on the reanalysis.

HURRICANE TRACK DATA ARCHIVE

This reassessment of the main archive for tropical cyclones of the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico was necessary to correct systematic biases and random errors in the data as well as to search for previously unrecognized systems.

A reanalysis of the Atlantic basin tropical storm and hurricane database (вЂњbest trackвЂќ) for the period from 1921 to 1930 has been completed.

Hurricane track data