1. Parameterization of Cloud Microphysics Based on the Prediction of Bulk Ice Particle Properties. Part II: Case Study Comparisons with Observations and Other Scheme
Morrison et al. JAS (2015), p

2. Introduction
Liquid water: Cloud (< μm) growing mainly by vapor diffusion. Rain growing primarily by collision-coalescence
Ice particles have a wide range of densities and complex shapes A large sensitivity with ice is partitioned into categories, and changes in thresholds or rates for conversion between ice species in simulations.
Predicted Particle Properties (P3) scheme total ice mass (qi), ice number (Ni) ice mass from rime growth (qrim), bulk rime volume (Brim)

3. Case descriptions and observations I
Midlatitude squall line
19 June 2007
(From Morrison et al. 2012)
KOUN (WSR-88D) Radar

4. Case descriptions and observations II
Extratropical cyclone-orographic forcing
13-14 December ● Strong southwesterly flow impinged on the higher terrain of the Cascade mountain range ● significant vertical motion ● enhancement of precipitation
From Milbrandt et al. (2008)
Washington
Portland radar WSR-88D (0.5o PPI)
Oregon

5. Model description and setup
WRF 3.4.1
Microphysics schemes: P3 scheme, Milbrandt-Yau (MY2), Morrison scheme (MOR-G, MOR-H), Thompson (THO), Stony Brook University-Lin (SBU-LIN), National Oceanic and Atmospheric Administration (NOAA)/National Severe Storms Laboratory (NSSL), WRF single-moment and double-moment 6-class (WSM6 and WDM6)
Scheme
Mass Variables
Number Variables
MY2
Qc, Qr, Qi, Qs, Qg, Qh
Nc, Nr, Ni, Ns, Ng, Nh
MOR-H, MOR-G
Qc, Qr, Qi, Qs, Qg
Nr, Ni, Ns, Ng
NSSL
SUB-LIN
Qc, Qr, Qi, Qs
THO
Nr, Ni
WSM6
WDM6
Nn, Nc, Nr

6. Model setup for the squall line
Model domain 612 × 122 km (Δx = Δy = 1 km) ztop = 25 km (100 levels)
Lamont, low levels (P >700 hPa) Norman, mid to upper (P ≦ 700 hPa) CAPE = 5990 J kg-1
u shear (perpendicular to the squall line) = 12 m s from surface to Z = 5 km

7. From Biggerstaff and Houze (1993)
FTR
RTF
OBS 30
~160
OBS
~160 30
@ 6h and Z ~ 1.1 km

8. Fr: mass fraction
mva: the crystal mass grown by vapor diffusion and aggregation mr: the total particle mass of a partially rimed crystal

9. Comparison of microphysics schemes

10. ~45 30
a very weak cold pool
@ 6h and Z ~ 1.1 km

11. obs
rapidly evaporated
rapidly evaporated

12. Horizontally and temporally (6~7 h) averaged
MY2
NSSL
MY2
NSSL
MY2

13. MY2
MY2
MY2
MY2 produces little trailing stratiform precipitation less snow due to too much cloud ice is produced and very little hail compared with graupel

14. Modified MY2 (WRF3.6)
much less cloud ice, more snow, and more hail

15. reduced fall speed
under- predict

17. the small D0 with rapid evaporation
The lowest-model-level 6h
NSSL
the small D0 with rapid evaporation
WDM6
WSM6

18. Model setup for the orographic precipitation case
From Milbrandt et al. (2008)
Portland radar WSR-88D (0.5o PPI)
Washington
Oregon
For IMPROVE-2 region
Cascade ridgeline
Model domain 1200 × 830 km2 (Δx = Δy = 3 km) ptop = 100 hPa (72 levels)
Forecast time from 0000 UTC 13 December to UTC 14 December
0000 UTC 14 Dec

19. @ 0000 UTC 14 Dec
@ windward side: qc > 0.5 g kg-1 below ~450 hPa Fr > 850 hPa ~ 750 hPa

20. Comparison of microphysics schemes
Accumulated surface precipitation (1400 UTC 13 Dec to 0800 UTC 14 Dec)
Terrain height (km)
＋ surface precipitation station ◇ lee of the Cascades (7)
◇ OBS

21. Precipitation differences 1400 UTC 13 Dec to 0800 UTC 14 Dec
MY2-P3
MOR-G-P3
MOR-H-P3
NSSL-P3
WSM6-P3
WDM6-P3
SBU-LIN-P3
THO-P3
P3-MOD-P3 (all ice is unrimed)
Precipitation differences UTC 13 Dec to 0800 UTC 14 Dec

22. 0000 UTC 14 Dec 1400 UTC 13 Dec to 0800 UTC 14 Dec ◇ OBS
MY2-P3
WSM6-P3
WDM6-P3
◇ OBS
2300 UTC 13 Dec to 0100 UTC 14 Dec

23. IWC (g cm-3)
2300 UTC 13 Dec to 0100 UTC 14 Dec
LWC (g cm-3)

24. Summary and conclusions I
Squall-line case: P3 run exhibited reasonable reflectivity and precipitation structure rimed-ice fall speed was critical for quall-line structure MOR-H, NSSL and P3 runs led to a well-defined leading convective region slower-falling graupel had lower peak rain rates at convective region all schemes underpredicted rain rates in the trailing stratiform region
under- predict

25. Summary and conclusions II
Orographic precipitation case: ●P3 produced greater windward and less leeward precipitation compared to other schemes ●