Frequently Asked Questions

About initial and boundary conditions

Q: How many vertical levels are there in experiment 1?
A: Forty two levels from 25 mb (1st level) down to 1050 mb (42nd) at 25 mb interval.

Q: Should there be a file which defines lat/lon for the half degree grid?
A: The domain configuration of the 0.5x0.5 degree lat/lon is as following: 

   NW corner  (1,YMAX).......................(XMAX,YMAX) NE Corner 

	      ...........(I,J)............... 

              ............................... 

              (1,2) .........................(XMAX,2)

   SW Corner  (1,1) .........................(XMAX,1) SE Corner
The lat/lon is at SW corner (130.0 W, 20.0 N), NE ( 70.0 W, 55.0 N), center (100.0 W, 37.5 N).

More information can be found at PIRCS domain on the Boundary Conditions Development Web page.

Q: I would like to know where I could get information on what the number means in the landuse file (i.e. LNDF60k.88051500)

A: First of all, the actual number in the file should be the max (14) minus this number. For example, 5 stands for 9 (=14-5).

  1. -- Urban land
  2. -- Agriculture
  3. -- Range-grassland
  4. -- Deciduous forest
  5. -- Coniferous forest
  6. -- Mixed forest and wet land
  7. -- Water
  8. -- Marsh or wet land
  9. -- Desert
  10. -- Tundra
  11. -- Permanent ice
  12. -- Tropical or sub-tropical forest
  13. -- Savannah

(Note: this list is adopted from MM5 documentation.)

Q: Is PIRCS dataset available at other sites aside from Iowa State University?

A: Yes. As a backup in case of network failure or slowness, we have loaded PIRCS dataset at NCAR. They are in MSS (mass storage system). The directories are:

         /ZPAN/PIRCS_EPRI/PSTDOM60k/PRCF60k.880515-31.tar
                                   /PRCF60k.880601-15.tar
                                   /PRCF60k.880616-30.tar
                                   /PRCF60k.880701-15.tar
         /ZPAN/PIRCS_EPRI/REGDOM0p5/PRCF0p5.880515-31.tar
                                   /PRCF0p5.880601-15.tar
                                   /PRCF0p5.880616-30.tar
                                   /PRCF0p5.880701-15.tar
These are large data files excluding smaller ones which can be easily downloaded by other means.

In order to download them, one has to have a "shavano" account at NCAR.

About output variables

Q: What is deep-soil heat flux in list of PIRCS-collecting variables?

A:The deep-soil flux is the net flux from the atmosphere into the model domain below the atmosphere. It is thus the flux across the interface from the atmosphere to the model's soil-vegetation domain.

Q: I would like to know how to define the mixed-layer depth, especially in cloudy conditions and night time.

A: Mixed-Layer Depth in PIRCS is defined based on the potential temperature profile. The top of the mixed layer should be the midpoint of the model layer closest to the surface for which the potential temperature change with height, d(theta)/dz, exceeds +1 K/km. In case of multiple such layers under cloudy conditions, only the FIRST one from the ground is considered. Please note that when the surface layer is stably stratified, the mixed layer depth is zero.

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