Kz diffusivity

[gws]

In a paper by Karion et al. (Intercomparison of atmospheric trace gas dispersion models: Barnett Shale case study. Atmospheric Chemistry and Physics, 2019. 19(4): p. 2561-2576), the authors write that

"For this reason, future work on the HYSPLIT dispersion model will focus on incorporating additional vertical turbulence parameterizations that are better able to mimic the mixing model in WRF-Chem. In one mixing parameterization that is currently being explored for HYSPLIT, the vertical eddy diffusivity for scalars, Kz, is exported directly from the underlying WRF transport and used in HYSPLIT in an attempt to mimic the mixing in WRF."

Has this progressed?
I was hoping to run HYSPLIT with different vertical mixing schemes for a special episode we're analyzing. The current tendencies observed suggest that HYSPLIT may underestimate surface layer concentrations on average, aka overestimates vertical mixing under certain conditions, similar to what Karion et al described.

[christopher.loughner]

Hi,

We have worked with this group at NIST to incorporate new beta turbulence parameterizations that closely follows what is done in WRF, but we have yet to fully evaluate these options.

Based on your results, I suggest running HYSPLIT with the STILT dispersion scheme (namelist option idsp=2). This new option became available last year and results in less boundary layer venting. See:

Loughner, C. P., Fasoli, B., Stein, A. F., and Lin, J. C. (2021). Incorporating features from the Stochastic Time-Inverted Lagrangian Transport (STILT) model into the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model: a unified dispersion model for time-forward and time-reversed applications. Journal of Applied Meteorology and Climatology (published online ahead of print 2021), available from: < https://doi.org/10.1175/JAMC-D-20-0158.1> [Accessed 14 May 2021]

[gws]

Thanks!
Yes, I was still running Version 4.2 ... now have the new version