1. Changes to the KPP Vertical Mixing Parameterization
G. Danabasoglu and W. G. Large
Shallowness of summer-time boundary/mixed layer depths
Presence of some grid-point noise in boundary /mixed layer depths, particularly in the Tropics
General review of physics and numerics
ENERGY INPUT AND DISSIPATION NOT CONSIDERED

2. TEST BED
x1 POP forced with QSCAT, NCEP, ISCCP, and MSU / Xie-Arkin data sets for July 1999 – December 2001
The initial conditions are for July 1, 1999, obtained from a 42-year forcing cycle experiment.
The results shown are from the last years of 2.5-year experiments.
Short-wave heat flux has a diurnal cycle.
For simplicity, the internal wave mixing is the only interior mixing allowed.

3. BOUNDARY LAYER DEPTH = HBLT = 0.3
This value of the critical bulk Richardson number is based on some sensitivity studies where comparisons with observed ocean responses during the Ocean Storm Experiment were made. The vertical grid resolution was 1 m.
Large et al. (1994)

4. CRITICAL BULK RICHARDSON NUMBER
Large et al. (1994) suggests that the critical bulk Ri should somewhat increase as the vertical resolution degrades.
Obtained by matching 1-m vertical resolution results

5. = 1.8
This value is chosen to satisfy the empirical rule of pure convection, i.e. the ratio of entrainment flux to surface buoyancy flux should be 0.2.
Large et al. (1994)
Obtained by satisfying the above rule
No dependence on resolution

6. BOUNDARY LAYER DEPTH
CONTROL
Ri and Cv MODS
Jan
July

7. TURBULENT VELOCITY SCALES
Figure 2 of Large et al. (1994)

8. QUADRATIC INTERPOLATION

9. BOUNDARY LAYER DEPTH
CONTROL
Quadratic Interpolation MODS
Jan
July

10. SUMMARY OF CHANGES Diurnal cycle in short-wave heat flux
Critical bulk Ri as a function of the vertical resolution
Cv as a function of N
Turbulent velocity scale limit in stable regions
Quadratic interpolation for HBLT
Use 4-pt maximum instead of 4-pt average for resolved shear
Modify usage of N in turbulent shear computation
Consider interior convection after HBLT is determined
Correct the Ekman and Monin-Obukhov depth limit computations

11. BOUNDARY LAYER DEPTH
CONTROL
All Physics MODS
Jan
July

12. SUMMARY OF CHANGES Diurnal cycle in short-wave heat flux
Critical bulk Ri as a function of the vertical resolution
Cv as a function of N
Turbulent velocity scale limit in stable regions
Quadratic interpolation for HBLT
Use 4-pt maximum instead of 4-pt average for resolved shear
Modify usage of N in turbulent shear computation
Consider interior convection after HBLT is determined
Correct the Ekman and Monin-Obukhov depth limit computations
Use OLDTIME level data in KPP to eliminate temporal noise
Use a Gaussian filter to smooth HBLT

13. BOUNDARY LAYER DEPTH
CONTROL
All Physics + Numerical MODS
Jan
July

14. MIXED LAYER DEPTH
CONTROL
All Physics + Numerical MODS
Jan
July

15. EQUATORIAL TEMPERATURE
LEVITUS
CONTROL
All MODS
Jan
July

16. EQUATORIAL TEMPERATURE
LEVITUS
CONTROL
All MODS
PMEL