The Advanced Regional
Prediction System

ARPS 4.0 Official Release Announcement

To:    All Users of the CAPS Advanced Regional Prediction System
From:  Model Development Group, Dr. Ming Xue, Director
Date:  15 September 1995
Subj:  CAPS Announces the Formal Release of ARPS Version 4.0

Version 4.0 of the Advanced Regional Prediction System (ARPS), developed at Center for Analysis and Prediction of Storms (CAPS), University of Oklahoma, was officially released on September 15, 1995. To obtain the source code, simply ftp to ftp.caps.ou.edu and log in as anonymous, sending your full e-mail address as a password. Then, cd to pub/ARPS and get the file arps_current.tar.Z.

The ARPS 4.0 User's Guide in PostScript format is in file arps40.docs.ps.tar.Z. A brand new capability allows users to view the Guide, chapter by chapter and page by page, on our World Wide Web page using the Portable Document Format (PDF). The associated files are in arps40.docs.pdf.tar, and will soon be accessible directly from our web page (http://www.caps.ou.edu), as will the source code itself. Please note that free PDF readers (Adobe Acrobat Reader) for Machintosh, Windows and most popular UNIX platforms are available from Abode Systems Inc. (http://www.adobe.com, or ftp://ftp.adobe.com).

Hardcopies of the ARPS 4.0 User's Guide can be obtained by writing to arpssupport@ou.edu. Given the much larger size of the new Guide (about 3 times thicker than the previous version) and increased printing costs, users will be required to purchase a hardcopy. The price will be somewhere between $30 and $50, and copies will be available in about 2 weeks.

For those who are new to ARPS, please read Chapters 1, 2 and 3 of the Guide first before downloading the entire ARPS source code and the supporting data files. Those who plan to use ARPS in any way are REQUIRED to SIGN and RETURN the registration form provided at the end of the User's Guide.

Although a full summary of Version 4 capabilities can be obtained from the user's guide, below are the principal improvements since the release of ARPS 3.0 some two years ago:

• 4th order spatial finite difference option
• Vertically semi-implicit option
• Implicit option for small timesteps (acoustic modes)
• Vertically-stretched grid option (structure defined analytically by the user)
• 3-category ice microphysics (cloud ice, snow, and graupel/hail)
• 1.5-order TKE subgrid closure model with iso/anisotropic options
• Kuo cumulus parameterization
• Stability-dependent surface fluxes
• Surface energy and moisture budgets, including landform characteristics
• Two-layer diffusive soil model with surface energy budget
• USDA surface characteristics database
• Automated domain translation
• Improved wave-radiating lateral boundary conditions
• Options for forcing the lateral boundaries from other models (e.g., RUC)
• Ability to accommodate horizontally inhomogeneous initial data from other models
• Global terrain database for the terrain-following vertical coordinate
• IEEE and NetCDF history dump formats (GRIB now in beta test)
• Updated and enhanced user's guide/tutorial
• Namelist format for all input files
• Greatly enhanced ARPSPlot post-processing graphics software
• New single-script makefile with numerous options
• PVM version of ARPS for message-passing architectures

• Germano dynamic subgrid closure
• Adaptive mesh refinement (grid nesting) from W. Skamarock
• Forward variational data assimilation and thermodynamic retrieval package
• ARPSTools post-processing software
• Adjoint of the ARPS (dry version to date)
• X-window interface for ARPS and ARPSPlt
• ZXPLOT library object code (underpinning for ARPSPlt)

For more information, send e-mail to: arpssupport@ou.edu or contact

Model Development Project
Center for Analysis and Prediction of Storms
University of Oklahoma
Sarkeys Energy Center, Room 1110
100 East Boyd
Norman, Oklahoma  USA  73019
Phone:  (405) 325-0453
FAX  :  (405) 325-7614
http://www.caps.ou.edu/ARPS/

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