EGU23-3553, updated on 22 Feb 2023
https://doi.org/10.5194/egusphere-egu23-3553
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A positive definite solution for an EDMF PBL scheme that includes a moist adjustment process

Jian-Wen Bao1, Evelyn Grell1,2, Sara Michelson1,2, and Song-You Hong1,2
Jian-Wen Bao et al.
  • 1NOAA/PSL, Forecast Model Development, Boulder, CO, United States of America (jian-wen.bao@noaa.gov)
  • 2CIRES, University of Colorado, Boulder, CO, USA

The eddy diffusivity and mass flux (EDMF) scheme for simulating turbulent transport in the operational Global Forecast System (GFS) shows a behavior due to a physical and numerical inconsistency in the scheme's numerical procedure to obtain detrained cloud water due to the moist nonlocal mixing and its associated moist adjustment.  One-dimensional simulations show that such inconsistency leads to an unphysical distribution of thermal tendencies and detrained cloud water near the simulated planetary boundary layer (PBL) top.  To solve this problem, a new procedure to obtain a positive definite solution from the scheme is proposed to solve the EDMF equations in the scheme. We will show the impact of this new solution procedure on the GFS performance.

How to cite: Bao, J.-W., Grell, E., Michelson, S., and Hong, S.-Y.: A positive definite solution for an EDMF PBL scheme that includes a moist adjustment process, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3553, https://doi.org/10.5194/egusphere-egu23-3553, 2023.