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Collaborative Radar Acquisition Field Test

(CRAFT)


Coordination with the University of Oklahoma (OU) and the Center for Analysis and Prediction of Storms (CAPS), the University of Washington, and the NEXRAD Operational Support Facility  (OSF) has been progressing rapidly.   Prior meetings in  February, 1998 ,  and  March, 1998  took place to discuss the issues of how best to work together to gain access and distribution to level II radar data on behalf of the university research and education community.

The Collaborative Radar Acquisition Field Test (CRAFT) is launched!

A meeting in Norman on September 10-11, 1998, attended by  Harry Edmon, University of Washington, Russ Rew and Linda Miller from Unidata,  Kelvin Droegemeier, CAPS, Tim Crum, OSF, and many other representatives from Oklahoma groups successfully provided a kick off  for this prototype project. The use of the LDM/IDD technology will eventually provide access and distribution of NEXRAD Level II data to a broader community.

The next  SAMEX  experiment to be conducted in spring of 1999 is providing some momentum for the CRAFT project to move on a fast track to provide access and distribution of Level II  data from several radars (~ to 9) in the area of Oklahoma, Texas, Arizona, NM, and Kansas.

Kelvin Droegemeier provided a planning  schedule .  Keith Brewster provided a brief  summary of the September meeting.  Following are excerpts from trip reports produced by Droegemeier, Brewster and Russ Rew, and information gleaned at the Oklahoma meeting.

Why Level II data?

Kelvin Droegemeier gave a briefing which depicted the impact on storm-scale NWP of using NIDS versus wide band data. Three different experiments were made using the ARPS model at 2 km resolution over all of Kansas and Oklahoma. The model was applied to the Lahoma, Oklahoma supercell storm, which began as a multicell in central Kansas, became a supercell as it moved southward into Oklahoma, and eventually became a bow echo in north Texas. Overall it had a lifetime exceeding 8 hours.

In all experiments, the ARPS was initialized using the RUC analysis to provide the background fields, to which were assimilated Oklahoma Mesonet, wind profiler, and SAO surface observations. A run using this configuration was compared to an experiment in which NIDS reflectivity data were also added (including various assumptions about the motion and other water substance fields), and to an experiment in which the same storm was initialized using full WSR-88D level II data and the Shapiro single-Doppler velocity retrieval scheme (which provides high-resolution cross-beam and vertical winds, along with temperature and pressure fields). All forecasts were run for 2 hours and 20 minutes:

Without any radar data at all, the model never generated a storm. With NIDS data added, the storm died out within 30 minutes. With full level II data used instead of NIDS, the isolated intense storm maintained its structure, as observed, and moved in the correct direction. These runs clearly show that, without full wide band data, storm-scale NWP will, in many cases, simply not be possible (of course, when forcing is strong, e.g., in terrain, along fronts and drylines), the importance of wide band data becomes more problematic.

Proving the practicality of archival, retrieval, and generation of gridded assimilated data sets
from level II data would move the U.S. forward in small-scale numerical weather prediction
(NWP). Droegemeier hopes to create a prototype system that NOAA could adopt. He hopes the
success of the prototype will be a springboard for proposals to take advantage of the wideband
data, such as:

Universities are showing particular interest in operational NWP.  Level II data should be valuable in providing temporal and spatial resolution for model data assimilation.

Numerous Players:

The players in a proposal to establish a WSR-88D Level II Data Acquisition Testbed (extracted from Droegemeier's presentation) are:

CAPS (Center for Analysis and Prediction of Storms)
       currently ingests level II data from KTLX, can provide fully 3-D gridded datasets.
        Also, Coordinator of Project SAMEX.
OSF (NWS WSR-88D Operational Support Facility)
       coordinates and manages RIDDS connection requests
NSSL (National Severe Storms Laboratory)
       installs and maintains RIDDS, develops software and runs RIDDS sites for WDSS
CCG (Center for Computational Geosciences)
       developed DoRaDa software that puts level II data on CD-ROM for PC-based analysis
       program
Oklahoma State Regents for Higher education
       operates a sophisticated Oklahoma-wide network infrastructure (OneNet); wants to see
       it pushed to capacity; has agreed to fund all networking costs, computer ingest hardware;
       coordinates link to vBNS and Abilene
UCAR/Unidata
       developers of LDM software, IDD system; has a complete data distribution infrastructure
       already in place; can adapt to the level II data from multiple radars
University of Washington
       Harry Edmon wrote software to conduct level II access experiment at the Univ of Washington
       based on their Unidata LDM/IDD system
NOAA Forecast Systems Labs
       also working on level II data acquisition

Testing Underway

Harry Edmon provided technical guidance to the Oklahoma contingent on installation of the software that has been successfully employed at the Univ of Washington for moving the Level II data. Harry's prototype installation was successfully delivering radar data starting on the afternoon of the first day of the meeting. Edmon created a document describing the LDM NEXRAD Level II format and diagrams showing the data flow using the RIDDS circular buffer and reading data directly from the network. Other major issues being addressed by the group are compression, bandwidth limitations, systems (Unix, PCs,), RIDDS future (open RPG), etc

The University of Washington is sending KATX (Seattle) data to OU, and OU is sending KTLX data to WA as a test of the data distribution. Testing on the KTLX continues and should lead to additional radars being implemented in preparation of the SAMEX 1999 experiment.

The group will continue to monitor the plans for 1999 and beyond, after the current NIDS contract expires. There is an AMENDMENT to the Agreement for Direct Real-Time Access to WSR-88D Wideband Data (Base Data) by Universities that was prepared by NOAA for users of the Level II (Wideband Data).

Communication

To facilitate communication, Unidata has created an email list <craft@unidata.ucar.edu>. Contact <support@unidata.ucar.edu> if interested in participating.

Linda Miller lmiller@unidata.ucar.edu

Questions or comments can be sent to lmiller@unidata.ucar.edu

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