NCEP RSM Frequent asked questions Page

GENERAL QUESTION:

What is RSM?

RSM stands for Regional Spectral Model, which is a limited-area atmospheric model using spectral method for computation.

What is the model dynamics and physics in RSM?

RSM has two model dynamic options, hydrostatic and nonhydrostatic. It uses NCEP global model's physics but has its own mesoscale physics, such as prognostic cloud scheme.

What applications has RSM been used?

Daily weather forecast, regional climate, regional enhancement of ReAnalysis, regional ensemble, provide its products for air pollution, volcanic ash and forest fire weather.

Which machine can RSM run?

The original code of RSM is designed for CRAY machine by FORTRAN 77, but there is a compile option to make it machine independent as a so-called portable code. It was running on CRAY C90, CRAY J90, IBM risc, HP UX, DEC alpha, SGI indy etc.

Is RSM a NCEP operational model?

RSM is developed at NCEP, and is operationally to support Hawaii daily weather forecast starting June 1997 and possible for North Atlantic aviation forecast.

Can I have a copy of the RSM for local machine?

You can get a copy from EMC/NCEP by a request letter to the Director of NCEP.

Who is the contact person for RSM?

Hann-Ming Henry Juang

US(301)7638000x7260

henry.juang@noaa.gov

CODING QUESTIONS:

Is there Y2K problem in the code?

Yes, if you got source code by March 1999, you have to check these.!

Two places to check your code for Y2K problem:

1) The first is in GLOOPR and RSRLOOPR for radiation

change following two lines

KYEAR = IYR

IF( IYR.LE.100) KYEAR = 1900 + IYR

KYEAR = IYR

IF( IYR.LE.100 ) KYEAR = 2050-MOD(2050-IYR,100)

2) The second is in GRIBIT
before the line
C FILL PDS PARAMETERS
add following line
C FIX YEAR AND CENTURY
      IYR4=IYR
      IF(IYR.LE.100) IYR4=2050-MOD(2050-IYR,100)
      IYC=MOD(IYR4-1,100)+1
      ICY=(IYR4-1)/100+1
Then
change
      IPDS(12)=IYR     ! YEAR OF CENTURY
to
      IPDS(12)=IYC      ! YEAR OF CENTURY
And change
      IPDS(23)=20         ! CENTURY
to
      IPDS(23)=ICY      ! CENTURY
That's all.
However, this fix is for two digit year up to year 2050, we suggest the input files should have 4 (or say full) digits of year. If full digit year is used, this fix can be forever, and the IF statement can be deleted.