1

Use and Abuse of MM5

Chris Davis

NCAR (MMM/RAP)

Acknowledgements: Fei Chen, Kevin Manning, Simon Low-Nam,

Jimy Dudhia, Jim Bresch, Wei Wang

Presented at COMAP Symposium 99-1Thursday, 20 May 1999

2

The MM5 modeling system flow chart*

*from MM5 tutorial

3

Schematic representation of the vertical structure of the model. The example is for 15 layers. Dashed land solid lines denote half- and full-sigma levels, respectively.*

*from MM5 tutorial

4

Example of a nesting configuration. The shading shows three different levels of nesting.*

*from MM5 tutorial

5

Physics Options in MM5

Cumulus ParameterizationsNone

Anthes-Kuo

Grell

Arakawa-Schubert

Fritsch-Chappel

Kain-Fritsch

Betts-Miller

Shallow Cumulus

6

PBL Schemes

• None• Bulk PBL• High-resolution Blackadar PBL• Burk-Thompson PBL• MRF PBL

7

Explicit Moisture Schemes

• Dry• Stable Precip• Warm Rain• Simple Ice (Dudhia)• Mixed-Phase (Reisner)• Goddard microphysics• Reisner graupel

8

Radiation Schemes

• None• Simple cooling• Suface radiation• Cloud-radiation scheme• CCM2 radiation scheme

9

Ground Temperature Schemes

• None• Force/restore (Blackadar) scheme

10

PBL and

SURFACELAYER

11

Diurnal cycle: Comparison of 2-meter temperature for MM5 with Slab surface model, MM5 with new Land Surface Model (LSM), and observations from FIFE.

12

Diurnal cycle: Comparison of various surface quantities for MM5 with Slab surface model, MM5 with new Land Surface Model (LSM), and observations from FIFE.

Incoming Solar Latent Heat Flux

Surface Radiation Sensible Heat Flux

13

q (g/kg)

Mixing ratio at lowest model level compared to FIFE observations.

14Profiles of potential temperature at selected times: comparison of MM5 with FIFE

observations.

1200 Z 1530 Z

1830 Z 2330 Z

15

Comparison of MM5 forecasts with RAOB data over the western U.S. from WISP’94.

16

Comparison of MM5 forecasts with RAOB data over the CONUS from WISP’94.

17

Distribution of the Scottish haar

NOAA-8 1448 GMT 27 APRIL 1984

NOAA-7 0836 GMT 27 APRIL 1984

18MM5 forecasts of the Scottish haar.

0800 UTC 1600 UTC

19

COMPLEXTERRAIN

20

4-domain configuration of MM5 for simulations over complex terrain of western Utah. Timeline of forecast cycle shown at bottom.

21

10-hour MM5 forecast on Domain 3 (3.3 km) of near-surface winds and potential temperature valid 2200 UTC 9 September, 1997.

22

4-hour MM5 forecast on Domain 4 (1.1 km) of near-surface winds and potential temperature valid 2200 UTC 9 September 1997.

23

Analysis of surface streamlines from Utah mesonet data on Domain 4 (1.1 km) for 0000 UTC 10 September 1997.

24

• Mean absolute errors for 24-hour lagged persistence forecasts of surface meridional wind component.

• Mean absolute errors for MM5 forecasts of surface meridional wind component.

• Difference between persistence and MM5 forecasts. Blue bar indicates differences that are statistically significant at >95% confidence level.

25

Time-averaged MM5 24-hour forecasts and observations of surface temperature ( C) and wind (long barb = 1 m/s) valid at 1200 UTC for November-December 1997.

26

CONVECTION

27

HURRICANE OPAL

28

48-hour MM5 prediction of Hurricane Opal valid 1200 UTC 4 October 1995: left is Betts-Miller cumulus scheme, right is Kain-Fritsch scheme.

29

48-hour MM5 prediction of Hurricane Opal valid 1200 UTC 4 October 1995: left is Betts-Miller cumulus scheme, right is

Kain-Fritsch scheme.

30

72-hour MM5 prediction of Hurricane Opal valid 1200 UTC 4 October 1995 using Betts-Miller scheme with continuous data assimilation supplying boundary conditions.

31

THE 1997 FORT COLLINS

FLASH FLOOD

32

33

Real-time MM5 9-km forecast of accumulated precipitation between 0000 UTC and 0600 UTC 29 July 1997.

34

Retrospective MM5 9-km simulation of accumulated precipitation between 0000 UTC and 0600 UTC 29 July 1997.

35

Retrospective MM5 3-km simulation of accumulated precipitation between 0000 UTC and 0600 UTC 29 July 1997.