A Global Super Best Track for Tropical Cyclone Forecasting and Research

The superBT is a TC-centric superposition of reanalysis (NWP-dynamics) and precipitation (thermodynamics) datasets onto TC track data from the two US operational forecasting centers:  the Joint Typhoon Warning Center (JTWC), Pearl Harbor HI and the National Hurricane Center (NHC), Miami FL.

The superBT can be thought of as a Best Track dataset with additional variables related to TC intensity and structure change (e.g., vertical wind shear and rainfall).

A special property of the superBT is that it includes a curated and unique set of both developing (9Xdev) and non-developing (9Xnon) pre/potential TCs (pTCs). Genesis is defined either as the first TC position in the best track or the time of the first warning/advisory.  Both JTWC and NHC are required to issue warnings/advisories on systems analyzed to be a TC regardless of initial intensity (maximum surface wind speed). Unlike IBTrACS, or the JTWC/NHC best tracks, the superBT TC (NN - 0-50) includes positions from the pTC (9Xdev) that became the TC.

Another special property of the superBT is the use of the twice-daily 10-d forecasts from the latest ECMWF Reanalysis v5 - ERA5.  The GFDL tracker (Marchok 2021) is run to generate TC track forecasts.  The quality of the ERA5 analyses, for TC applications, is assessed by the 'acid test of an analysis' i.e., a ‘good’ track forecast implies a ‘good’ analysis.  

The ERA5 forecast tracks are also used in calculating the ‘diagnostic’ file of environmental and storm parameters that are input to statistical-dynamical intensity prediction models (e.g., Knaff et al. 2019).  The tracks are also used to compare ERA5 model precipitation around the TCs in the superBT to three satellite precipitation analyses.