bl_pbl_physics

1. bl_pbl_physics Dan Harnos, Jessica Colberg, Joseph Ching, Michelle Pitcel

2. Scheme options • Option 1: YSU (Control) • Prognostic: none • Diagnostic: exec_h • Cloud mixing: QC, QI • Option 0: No PBL scheme • Option 5: MYNN2 • Prognostic: QKE • Diagnostic: Tsq, Qsq, Cov, exch_h, exch_m • Cloud mixing: QC

3. Winds are stronger (more mixing occurs) with boundary layer physics included. • More realistic as heating should induce mixing of the boundary layer • With no physics, minimal mixing occurs

4. Temperature appears to be independent of the scheme • Minimal differences appear with the varying model setups

5. Scheme 5 has the most definite layers of humidity between the 3 setups • Much more variation, although it seems this should indicate less mixing • This may be better handled by scheme 1

6. Vertical motion seems to vary minimally between all the schemes • Minimal differences appear with the varying model setups

7. PBL Scheme flux comparisons • Different • Net ground heat flux • Downward LW flux at surface • Upward LW flux at TOA • Upward sensible heat flux at surface • Upward latent heat flux at surface • Upward LW flux at Surface • Identical • Downward SW flux at surface • Upward SW flux at TOA • Downward SW flux at TOA • Upward SW flux at surface • Downward LW flux at TOA (zero)

14. Conclusions • Both PBL schemes show realistic boundary layer development with minimal differences. • No PBL scheme captures surface reasonably well, although BL features lack depth. • Diurnal cycle and temporal spacing captured well across all. • Selection of PBL scheme dependent upon your simulation • If ice in BL use option 1, etc.

15. Supplemental Content