Q1. What is “Super Resolution” WSR-88D data?

REPLY: Super Resolution data will provide: increased reflectivity data resolution by reducing gate spacing from 1 km to 250 m; increase azimuthal resolution of all three moments of data from 1° to 0.5°; and the extend the range of Doppler data from 230 km to 300 km.

Q2. Will “Super Resolution” WSR-88D data be available on all scans?

REPLY: Super Resolution data initially will be produced only during the “split cuts,” those scans at or below 1.5°. (Note, volume coverage pattern (VCP) 31 also has a split cut at the 2.5° scan, thus Super Resolution data will be available at that scan too.)

Q3. What are the advantages of Super Resolution WSR-88D data?

REPLY: Super Resolution data should lead to increased tornado warning lead times. Simulations using Super Resolution data show that mesocyclone and tornado signatures can be detected at greater ranges than with legacy resolution data. In addition, other smaller scale features should be detectable in base products sooner or with greater reliability.

Q4. Why send Super Resolution data in the Level II data stream?

REPLY: Level II have always been defined as the highest resolution data the WSR-88D produces. Super Resolution data will be in the Level II data stream between the Radar Data Acquisition (RDA) and Radar Product Generator (RPG) and will provide NWS forecasters these data to better support forecast and warning operations. Being able to include Super Resolution data in the Level II Data Collection and Distribution Network will enable external users to experience the advantages of Super Resolution data in real time and meet NWS requirements for these data in the NCDC archives.

Q5. Why does the format of the Level II data need to change in Build 10?

REPLY: We need to change the format because the legacy “MSG1” format does not support Super Resolution unless radials become segmented (2432 block segments) and it does not support Dual Polarization Level II data. Thus, we need to change the message format by Build 11, when Dual Polarization data will become available, to “MSG31.” We believe it is better to make these changes in one build rather than to implement them separately in two consecutive software builds.

Q6. Why change the Level II data format in Build 10 if it is possible the NWS may not have the funding needed to increase the communications links to send Super Resolution data?

REPLY: Irrespective of NWS funding of collecting and distributing Super Resolution data available in real time across the Level II network, the NEXRAD Program needs to make the change of data format to MSG31 to support the RDA-RPG communications link for Super Resolution and Dual Pol data. If the NWS initially does not have the funding to begin collecting and distributing Super Resolution data with the deployment of Build 10, the NWS might be able to do so at a later date. To not add this capability in Build 10 would mean we definitely would not be able to collect and distribute Super Resolution data until at least Build 11.

Q7. Will there be a capability to change the transmission of Level II data from recombined (legacy resolution) data to/from Super Resolution data?

REPLY: Yes. This will enable the NEXRAD Program to turn on the distribution of Super Resolution data if funding for the upgraded communications becomes available after deployment, if not initially available. Changes in sites’ transmission of recombined data to/from Super Resolution data will be announced to users with a proposed implementation schedule for the affected sites in advance.

Q8. How much will the Level II data rate change with Super Resolution data?

REPLY: During the course of a complete volume scan the overall data rate will increase approximately by a factor of 2.3. However, during the faster VCPs and with a lot of weather echoes, the data rate in the split cuts can increase by up to a factor of 5. The NWS analysis shows that we will need to expand the bandwidth available per radar from today’s 128 kbps to 384 kbps to ensure timely delivery of the data.

Q9. What options are available if I don’t need Super Resolution data?

REPLY: You can use an algorithm to recombine the Super Resolution data into a legacy-like resolution. The RPG will use the Recombination Algorithm to support algorithms and products that require legacy resolution data and therefore it will be included with the Common Operations and Development Environment (CODE). Information on where to find the Recombination Algorithm source code on the CODE web site can be found at: http://www.weather.gov/code88d/message31.html. The Recombination Algorithm has been developed and tested by the NSSL to provide legacy resolution data that provides RPG algorithm performance very similar to the results if the data were originally collected at the legacy resolution.

Q10. Will all sites be able to produce Super Resolution data?

REPLY: No. The Evansville, IN weather radar (KVWX) will not have this capability. The Level II data for KVWX will continue to use the MSG1 format and have legacy resolution data.

Q11. Can you provide references concerning the Super Resolution data?

REPLY: There are two references we suggest which discuss Super Resolution data and the Recombination Algorithm:

Torres, S. M. and C. D. Curtis, 2007: Initial implementation of super-resolution data on the NEXRAD network. Preprints, 23rd Conf. on Interactive Information Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Antonio, TX.

Torres, S. M. and C. D. Curtis, 2006: Design considerations for improved tornado detection using super-resolution data on the NEXRAD network. Preprints, Third European Conf. on Radar Meteorology and Hydrology (ERAD), Barcelona, Spain, Copernicus.

Q12. When will user software need to be ready to ingest the new Level II format (MSG31)?

REPLY: The Level II transmitted from sites, except for Evansville, IN (KVWX) will change to the new format as Build 10 is loaded on each WSR-88D. Thus, users will need to be ready for the new format when Build 10 is loaded on the first Build 10 Beta Test site, now planned for the week of 6 March 2008. The ROC will publish a Build 10 Beta Test schedule and post the planned release dates of Build 10 software in advance. Except for Beta Test sites, sites will have 60 days to install Build 10 after receipt of the software.

Q13. Will our Level II data decoders need to be able to handle more than one Level II format and data resolution?

REPLY: Yes. Users’ Level II software will need to be flexible to ingest both MSG1 and MSG31 format data; and legacy/recombined resolution data or Super Resolution data as there will be combinations of these data being transmitted from sites beginning with the Build 10 Beta Test start.