SR/SSD 98-33


Technical Attachment

SCAN Test at WFO Tulsa

JT Johnson

National Severe Storms Laboratory

Steve Amburn

WFO Tulsa, OK

What is SCAN?

SCAN is the System for Convective Analysis and Nowcasting. It is being developed as an automated system to assist the forecaster in warning operations and decision-making. The goals of SCAN are:

What is the Current Status of SCAN?

SCAN currently consists of the National Severe Storms Laboratory's (NSSL) Warning Decision Support System (WDSS), the National Center for Atmospheric Research's (NCAR) Auto-nowcaster, and the NWSH Techniques Development Laboratory's (TDL) Thunderstorm Product and QPF products. The SCAN prototype was installed last year at NWSFO Sterling, Virginia. During the summer of 1997, the SCAN prototype was tested for two months with operational meteorologists. SCAN remains at Sterling for additional testing of prototype applications and display concepts, but the Sterling evaluation does not involve an AWIPS installation. Thus the SCAN prototype is a "stand-alone" system with a direct connection to Sterling's WSR-88D.

Parts of SCAN are being integrated into AWIPS and others are planned for future AWIPS software builds. The TDL Thunderstorm Product is part of AWIPS 4.1 and parts of the NSSL WDSS are being tentatively planned for integration into AWIPS Build 5.0.

What is the Motivation for SCAN?

Why conduct a SCAN Test in Tulsa?

Installing SCAN at WFO Tulsa will allow forecasters there to help identify and develop new applications for operations because Tulsa offers two things that Sterling does not have - two radars and AWIPS. Several of the applications being considered for integration into AWIPS require input from multiple WSR-88Ds. The Tulsa WFO has two Radar Product Generators (RPGs) in the office, associated with radar at Tulsa and Fort Smith. Thus costs are greatly reduced for the test by not having to lease communications lines for the connections to two WSR-88Ds.

Tulsa's climatology for significant weather during the summer is also "ideal" for now providing extensive test opportunities. Additional factors facilitating research interaction at Tulsa are the WFO's proximity to NSSL, which cuts down on travel costs for the test, and OneNet (an Oklahoma based communications company) which allows communication of wideband WSR-88D data from all sites that cover the Tulsa CWA.

What would the Tulsa SCAN Test include?

The initial Tulsa SCAN Test will be a test of the applications that are targeted for AWIPS Build 5.0. This would include only a "limited-WDSS" functionality and not the TDL or NCAR applications.

Vision for Tulsa SCAN Testing

NSSL envisions that the equipment for testing SCAN functionality will remain in Tulsa for several years. The connections to the wideband data on multiple WSR-88Ds, the access to an operational AWIPS data feed, and low communications costs, make Tulsa an excellent location for continuing to test new SCAN prototype methods and techniques. The Tulsa office, in a sense, would become one of the SCAN test-beds, or SCAN proving grounds.

What is the impact on the AWIPS?

The SCAN prototype for Tulsa consists of four additional machines added to the AWIPS LAN. Two of these are Radar Ingest and Data Distribution System (RIDDS) machines, connected directly to the RPG (one each for Tulsa and Ft. Smith RPGs). The other two machines are algorithm processing computers. These are essentially the WDSS equivalent of the RPG. These algorithm machines ingest radar data from RIDDS (one algorithm machine connected, via 10BaseT direct connection, to one RIDDS machine). The algorithm machines produce products (images, etc.) displayable on each of the AWIPS workstations.

The AWIPS workstations have user accounts dedicated to the running of the WDSS/SCAN display. Several files have been installed in the user accounts on each of the individual workstations in order to establish the correct functional environment for the WDSS/SCAN display. The total amount of disk space for the installation on each workstation is approximately 45 MB.

The AWIPS workstations run the display client of the WDSS/SCAN display and connect to the display server on the algorithm machines. The data on the algorithm machines are then passed over the AWIPS LAN to the AWIPS workstations and read into memory for the WDSS/SCAN display.

Summary...What are the implications of all this for other NWS offices?

Ultimately, SCAN testing should provide a better final software package for implementation in the AWIPS environment for all NWS offices. SCAN will enhance the integrated approach to weather analysis, forecasts and warnings. Algorithm output and data display methods can be tested and checked for completeness, applicability, and usefulness. Also, development and testing of algorithms which use data from multiple radars may lead to new and better warning and nowcasting techniques.