NEXRAD Dual-Polarization Product Review

Kevin ScharfenbergOU-CIMMS and NOAA-NSSL

2nd Workshop on NWS Severe Weather Warning Technology -- 10 July 2007 -- Norman, OK

Dual-pol product field evaluation

•Conducted Autumn 2006

•8 WFOs (Duluth, Melbourne, Norman, Pittsburgh, Sacramento, St. Louis, Sterling, Tucson)

•Several other agencies (RFC-Tulsa, Lincoln Labs, DoD, etc.)

•Online training modules provided by WDTB

•Used WDSS-II software to interrogate data

Dual-pol product field evaluation

Seven cases from KOUN prototype dual-pol WSR-88D

- 14 May 2003: Widespread hail, heavy rain, considerable non-precipitation echoes- 10 Jun 2003: Squall line, heavy rain- 29 May 2004: Tornadic high-precipitation supercell- 22 Dec 2004: Light-moderate snow- 5 Jan 2005: Rain and freezing rain, some sleet- 28 Jan 2005: Heavy snow & light drizzle/mix- 2 May 2005: Light rain, low 0ºC level

Dual-pol product field evaluation

•Online worksheets and questionnaires

•Evaluation of how the products might be used in the office’s operations

•Base products and algorithms

•Also considered user factors (e.g., data displays, cursor readouts, etc.)

Dual-pol product field evaluation

Dual-pol product field evaluation

Dual-pol product field evaluation

Norman working group experienced with KOUN data and technology transfer to operations concurrently evaluated products and analyzed field feedback

Wrote basic findings & recommendations for final report

Formed “needs assessment” and determined priorities

Base Products

ZDRhv

KDP

Hydrometeor Classification Algorithm

No echoLight/moderate rainHeavy rain

Rain/hail“Big drops”Biologicals

AP/ground clutterUnknownDry snow

Wet snowCrystalsGraupel

Other products

•Rainfall algorithms – Undergoing major revisions during field evaluation phase so could only be generic

•Melting layer algorithm – no stand-alone output yet to evaluate, but critical to understanding hydrometeor classification algorithm (and later, rainfall algorithms)

•“Filtered reflectivity” product – uses hydrometeor classification to filter out non-precip echoes from reflectivity product

Results•Use of base products to form a 4D conceptual model

•Base products at highest-possible resolution, data precision

•Broad-based training will be critical for success

•Flexible, innovative display concepts needed

•The “black box” algorithm problem

Results, continued

•Hydrometeor classification – melting layer – rainfall algorithms intertwined, still in developmental stages

•Need to keep users in the loop as algorithms are refined

•Product color schemes need to be unique for quick identification

•Product toggles, cursor readouts, etc. should be reexamined

Results, continued

•Wide variety of end-users

•Numerous software considerations (FFMP, clutter canceling, etc.) – some unknowns

•Primary focus should be on highest-quality base data for users, software, algorithms, etc…

•Downstream users can do the slicing & dicing

•What about user-adaptable parameters and other NEXRAD initiatives (super-resolution, new VCPs, etc.)?

Setting an aggressive agenda for change

•In my opinion, hydrometeor classification, rainfall accumulation, and other algorithms will be much more successful by incorporating multiple radars and other data sources

•Must also coordinate operations concept with ongoing transition to “warn-on-forecast” models, gridded warnings, etc.

•Also must keep in mind new technologies like FSI, AWIPS2, other radar upgrades, new radars, etc.

Setting an aggressive agenda for change

Discussion…

Push toward incorporation of multi-radar, multi-sensor products into routine NWS operations so we are prepared to take advantage of dual-pol capabilities

Think outside the box on visualization for complex data interrogation

Strive for the best possible training

Kevin.Scharfenberg@noaa.gov