The graphics in this archive use the two objective metrics created by and detailed in Ditchek et al. (2019a) and Ditchek et al. (2019b) to identify pulse type and electric activity in Atlantic basin tropical cyclones (TCs), respectively. For details on data sets used and how to download the graphics in the archive, please see the README. For brief details on the criteria for both objective metrics and their associated terms and definitions, expand the below.
To objectively identify pulse type, four criteria are used:
Cooling (Warming) Cloud Tops: lower (upper) quartile of 6-h IR BT difference values
On-The-Clock: spatial location of cloud tops follow the diurnal clock schematic (Ditchek et al. 2019a, Fig. 2b)
Areal Criterion: upper half of cloud-top areal coverage distribution
Longevity: number of hours in a given day where the above 3 conditions were satisfied to account for outward propagation
Pulse Type Terms and Definitions:
LLCP (long-lived cooling pulse): days that have on-the-clock cooling cloud tops that satisfy the areal criterion and exist for ≥9 h
LLWP (long-lived warming pulse): days that have on-the-clock warming cloud tops that satisfy the areal criterion and exist for ≥9 h
SLCP (short-lived cooling pulse): days that have on-the-clock cooling cloud tops that satisfy the areal criterion and exist for 3–6 h
SLWP (short-lived warming pulse): days that have on-the-clock warming cloud tops that satisfy the areal criterion and exist for 3–6 h
NP (no pulse): days that have no identifiable outward-propagating cooling or warming cloud tops, have cooling or warming cloud tops that do not satisfy the areal criterion, or have cooling or warming cloud tops that satisfy the areal criterion but exist for <3 h
To objectively determine electric activity, three criteria are used:
Pulse Lightning Flash Density: upper half of the distribution
Areal Criterion: upper half of pulse lightning areal coverage distribution
Longevity: number of hours in a given day where the above 2 conditions were satisfied
Electric Activity Terms and Definitions:
ACT (electrically active pulse): pulses that satisfy both the pulse lightning flash density and areal criterion and exist for ≥9 h
QUASI (quasi-electrically active pulse): pulses that satisfy both the pulse lightning flash density and areal criterion and exist for 3–6 h
INACT (electrically inactive pulse): pulses that do not satisfy both the pulse lightning flash density and areal criterion or exist for <3 h
I created this archive in order to document TC diurnal pulses in past storms.
If you're doing a case study and are presenting or publishing your work, or if you just want to share graphics from this archive on social media, please do!
All images in this archive are free to use and share - I just ask that you use the following citation:
GridSat-B1 is updated quarterly and WWLLN lightning flash data is updated daily.
Therefore, when HURDAT2 and SHIPS are updated with the previous season's best tracks and shear values, new graphics will be generated for the archive.