Why do you say that? Just looking at the plots in Prosser et al (2023) it is obvious they had a lot more years than just two.
If you actually read the short paper you'll find they actually used reanalysis data sampled at a rate of every three hours across 42 years to compute their statistics:
> Global ERA5 reanalysis data (Hersbach et al., 2020) [...] were extracted on the 197 hPa pressure level with 0.25° horizontal resolution at three hourly intervals from 1 January 1979 to 31 December 2020. To allow the computation of CAT diagnostics that require vertical derivatives, fields on the 188 and 206 hPa levels were also extracted. The 21 turbulence diagnostics were then calculated from the extracted reanalysis fields every three hours.
How you go from that to "they just looked at 2 years" is beyond me.
If you actually read the short paper you'll find they actually used reanalysis data sampled at a rate of every three hours across 42 years to compute their statistics:
> Global ERA5 reanalysis data (Hersbach et al., 2020) [...] were extracted on the 197 hPa pressure level with 0.25° horizontal resolution at three hourly intervals from 1 January 1979 to 31 December 2020. To allow the computation of CAT diagnostics that require vertical derivatives, fields on the 188 and 206 hPa levels were also extracted. The 21 turbulence diagnostics were then calculated from the extracted reanalysis fields every three hours.
How you go from that to "they just looked at 2 years" is beyond me.