LAPS Information Summary Website 
Last updated 4/8/03
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This web page has been put together to help potential LAPS users and provide consistent information with regard to LAPS frequently asked questions (FAQs). Most of this information is already available via the web through our README file. However, due to the increasing number if inquiries with regard to LAPS details, a webpage that focused on the FAQs from interested users was deemed appropriate. As inquiries are fielded by our LAPS staff, we intend to update this page as often as needed. This page also contains valuable links to a number of information sources that will help answer LAPS related questions. 

Topical index:

LAPS System Requirements:

What are typical disk space requirements for input data and generated output?

The current Colorado and AWIPS LAPS (domain size 61x61x21):

How much machine memory does LAPS need? Data specific information:

What data formats are used in LAPS?

NetCDF or ASCII data are used for output and most internal data storage. This way all data files are machine independent.

How does LAPS interface to my local datasets?

Each local installation requires unique routines to access local data. These local routines are the responsibility of the user and are linked and become part of the LAPS ingest software.

What satellite data does LAPS use?

Currently, LAPS uses GOES image data (visible plus IR channels 3, 4, and 5) and GOES sounder channels.  The current satellite for which an interface exists using the OPTRAN forward model is:

Bosnia prototype:

What are the data sets used in the Bosnia demonstration?

The following datasets are used in the Bosnia prototype at AFGWC:


What platforms has LAPS run on?

How much computer time is needed to run LAPS? Misc.

How many lines of code does LAPS contain?

LAPS contains approximately 180,000 lines of FORTRAN and 34,000 lines of C code.  There are additional lines for scripts, Make files and the like, but this give you a rough estimate.  This figure does not include any model code (e.g., RAMS or MM5); this is strictly analysis code.

Is LAPS Y2K Compliant?

The latest information on this is can be found on our Y2K page.

What is "newLAPS?"

During 1997 LAPS was recast into a more user friendly configuration format.  This new system comes with an auto-configure feature that will examine your system to see what operating system you have, what compiler settings are required, where special libraries exist (and if they don't it will let you know to get them before you proceed),  and then it allows you to specify directory paths for different aspects of the system.  Data, binaries, and source code can be separated to different user-defined paths.  The makefiles are automatically configured for your system and the system builds.

NewLAPS also contains better terrain data than Old LAPS.  (30 second for the entire globe)

What software is used to visualize LAPS?

IDL is now used for most web graphics. A plotting program using NCAR graphics is supplied with LAPS and is also used for some web graphics.

What are the critical datasets for LAPS?

Basically you need:

What happens if data sets fail to arrive in time for inclusion in a given analysis run?

LAPS is robust. However, given less data the analysis will be less and less accurate. It will run until the surface or background fields are not available.

Does LAPS use 3D Var (three dimensional variational analysis techniques)?

Not at this time. However, some aspects of LAPS utilize 1D var (surface temperature gradients from satellite data, upper level humidity adjustment from satellite data complete with forward model). We are pursuing an upgrade to 3Dvar and this is one of our current interests.

What does Hot Start mean?

Hot start is a jargon term that basically means the diabatic initialization of the model is achieved within the initial conditions provided by LAPS to a model.  Thus, the model has no inherent spin-up when it begins, since the mass fields are all in balance guaranteed by the LAPS "balance" modules.

What are the characteristics of the terrain data that LAPS comes with?

OldLAPS terrain file covers the entire globe with:

NewLAPS terrain covers the entire globe: Additional information:

More information can be found under our readme file:


Publications and documentation

LAPS publications can be found in a variety of locations, this is our best source of "documentation" at this time:

Additional reminders

Have you checked out our key homepages?

Additional information can be obtained in some of these LAPS information pages.

FSL's Disclaimer

These data and/or display products as well as their documentation are in the public domain and are furnished "as is." This data is research data and was collected with the intent of using it for meteorological research. The United States government, its instrumentalities, officers, employees, and agents make no warranty, express or implied, as to the accuracy, quality, completeness, continuity, timeliness, reliability, or the general usefulness of the data, products, and/or documentation for any purpose. They cannot be held responsible for any circumstances resulting from their use, unavailability, or possible inaccuracy. FSL will make data and/or display products available in World Meteorological Organization (WMO), FSL, or other standard formats which may change at times. FSL reserves the right to suspend or discontinue this service, or portions thereof, at any time.

Permission to use, copy, and distribute this data is hereby granted, provided that the entire disclaimer notice appears on all copies.


After examining this page and other LAPS web pages, additional LAPS inquiries should be directed to:

Dr. Daniel Birkenheuer CIRA, Forecast Systems Laboratory
LAPS Project Manager
d a n i e l . l . b i r k e n h e u e r (remove spaces and the e-mail address is valid)
(303) 497 5584

This page is maintained by Dan Birkenheuer