[AAS06-07] A Super Best Track Data Set for Tropical Cyclone Studies
★Invited Papers
キーワード：TC forecasting, reanalysis, TC activity, TC genesis
Deterministic track forecasts have become so accurate in the medium range (e.g., the mean 72-h position error of the global models is now below predictability ‘limits’) that long-term tropical cyclone (TC) studies and forecasting can move in new directions with different emphases. For forecasting two new directions are:
1) a more explicit (and better) prediction of the surface wind field (e.g., intensity and the wind radii); and
2) ‘completing the forecast’ with predictions of genesis (and dissipation).
For climate studies, the availability of high-resolution global reanalysis will allow a more in-depth examination of the relationship between TC activity and the tropical general circulation.
Current best track data sets have several deficiencies for both forecasting and climate research; specifically, they lack:
1) observational analyses of the surface wind field (e.g., the NOAA Multiplatform Satellite Surface Wind Analysis) and precipitation
2) position data in the pre/potential TC (pTC) genesis stage
3) a ‘diagnostic file,’ with environmental variables known to be related to intensity change, derived from high-quality and consistent global (re)analyses/forecasts (e.g., vertical wind shear)
4) track forecasts for both pTCs and TCs that include TC structure, e.g., pressure/radius of the outermost closed isobar
The foundation of the super best track (SBT) is the ‘final’ best tracks of the two US operational forecast centers – the Joint Typhoon Warning Center (JTWC) and the National Hurricane Center (NHC). The SBT is thus global and unique in three important ways by including:
1) pTC tracks taken from a curated archive of all (both ‘numbered’ and INVEST or 9X systems) working best track data from JTWC/NHC since 2007
2) dynamical environmental variables (analysis and forecasts) come the latest/greatest ECMWF reanalysis – ERA5 – that has the same resolution as the NWP global models circa 2015
3) satellite precipitation analyses
The initial version of the SBT covers a 13-year period 2007-2019 and after a short summary of SBT properties, the talk gives one application example for TC genesis. Version 2.0 will include the entire ERA5 period 1979-2020.
1) a more explicit (and better) prediction of the surface wind field (e.g., intensity and the wind radii); and
2) ‘completing the forecast’ with predictions of genesis (and dissipation).
For climate studies, the availability of high-resolution global reanalysis will allow a more in-depth examination of the relationship between TC activity and the tropical general circulation.
Current best track data sets have several deficiencies for both forecasting and climate research; specifically, they lack:
1) observational analyses of the surface wind field (e.g., the NOAA Multiplatform Satellite Surface Wind Analysis) and precipitation
2) position data in the pre/potential TC (pTC) genesis stage
3) a ‘diagnostic file,’ with environmental variables known to be related to intensity change, derived from high-quality and consistent global (re)analyses/forecasts (e.g., vertical wind shear)
4) track forecasts for both pTCs and TCs that include TC structure, e.g., pressure/radius of the outermost closed isobar
The foundation of the super best track (SBT) is the ‘final’ best tracks of the two US operational forecast centers – the Joint Typhoon Warning Center (JTWC) and the National Hurricane Center (NHC). The SBT is thus global and unique in three important ways by including:
1) pTC tracks taken from a curated archive of all (both ‘numbered’ and INVEST or 9X systems) working best track data from JTWC/NHC since 2007
2) dynamical environmental variables (analysis and forecasts) come the latest/greatest ECMWF reanalysis – ERA5 – that has the same resolution as the NWP global models circa 2015
3) satellite precipitation analyses
The initial version of the SBT covers a 13-year period 2007-2019 and after a short summary of SBT properties, the talk gives one application example for TC genesis. Version 2.0 will include the entire ERA5 period 1979-2020.