Dual-Polarization Operations Assessment Status Update on Development Process Progress on RDA work Progress on RPG work Where we are with Beta and Deployment

RDA Work Data Quality Team Data Quality Team – Many, many, many problems identified, researched and fixed – Training, engineering and research experts who meet regularly Beta test will be key… Beta test will be key… – Currently Scheduled for Dec 2010 – March 2011

What Dual-Pol Does Not Change Basic WSR-88D characteristics Basic WSR-88D characteristics – Frequency, beamwidth, data resolution VCP sampling VCP sampling – Elevations, update time, number of pulses per radial All Pre-Dual-Pol products and algorithms All Pre-Dual-Pol products and algorithms You control how and when you integrate Dual-Pol information into your methodology

Dual-Pol and CMD CMD will not be operational with initial deployment CMD will not be operational with initial deployment – Manual clutter management returns! Bypass Maps for normal clutter Bypass Maps for normal clutter All Bins for AP clutter All Bins for AP clutter CMD will return with the first full build after Dual-Pol CMD will return with the first full build after Dual-Pol – Build 13…scheduled Jan/Feb 2012 – Development work underway…

Dual-Pol and Sensitivity Sensitivity: ability to detect weak returns Sensitivity: ability to detect weak returns – Measured as ___ ___ range for returned signal = noise Affected by transmitted power and system noise Affected by transmitted power and system noise – If returned signal is above the noise, life is good!

Dual-Pol Sensitivity Loss Dual-Pol radars transmit and receive both horizontally (H) and vertically (V) Dual-Pol radars transmit and receive both horizontally (H) and vertically (V) – For same range, same target, WSR-88D Dual-Pol has less returned power than before

Dual-Pol and Sensitivity Dual-Pol sensitivity loss means more gates that are “Off” than before Dual-Pol sensitivity loss means more gates that are “Off” than before –Returned signal not processed into base data Detectable Not Detectable

Dual-Pol Sensitivity Loss A bit more loss from hardware that does the splitting A bit more loss from hardware that does the splitting Cabling, built-in test equipment, etc. Cabling, built-in test equipment, etc. Per site expected sensitivity loss due to Dual-Pol conversion 3.5 – 4 dB Per site expected sensitivity loss due to Dual-Pol conversion 3.5 – 4 dB Impact on operations?!!? Impact on operations?!!?

Dual-Pol Sensitivity Loss Impact on Operations? SME panel assembled to evaluate impact of 4 dB loss SME panel assembled to evaluate impact of 4 dB loss – ROC engineering, NWS SSDs, NSSL, and WDTB Spectrum of weather events evaluated Spectrum of weather events evaluated – 4 dB loss simulated (Don’t try this at home)

Dual-Pol Sensitivity Loss Impact on Operations Events evaluated Events evaluated – Dryline – KS (KDDC) – Freezing drizzle – KS (KICT) – Marginal lake effect snow – NY (KBUF) – Tornadic supercell along boundary – CO (KFTG) – Outflow boundaries from convection – OK (KTLX) – Short range smoke plumes – OK (KTLX) – Multiple outflow boundaries/popcorn showers – FL (KEVX) – California wildfires – CA (KSOX) – Hurricane Ike landfall – TX (KHGX) – Nor’easter snowstorm (snowmaggedon) – VA (KLWX) Go Paul!! Go Paul!!

Now For Calibration of Z Calibration is about the magnitude of Z values Calibration is about the magnitude of Z values KCRI 0.5˚ KOUN 0.5˚

Calibration of Z Given appropriate Z calibration and same scatterers in a volume Given appropriate Z calibration and same scatterers in a volume –40 dBZ is 40 dBZ, 30 dBZ is 30 dBZ, etc. –Assuming Rayleigh scattering… Work is ongoing Work is ongoing –Z calibration –ZDR calibration

Sensitivity and Calibration Summary Sensitivity: more Off gates with Dual-Pol Sensitivity: more Off gates with Dual-Pol – Per site expected sensitivity loss due to Dual- Pol conversion 3.5 – 4 dB Less return from very weak signal areas Less return from very weak signal areas Z Calibration: magnitude that is assigned Z Calibration: magnitude that is assigned – Dual Pol calibration much more complex Be kind to your techs! Be kind to your techs! – 8 hour check no longer transparent

Now For Attenuation Impact on base moments does not change Impact on base moments does not change Impact on Dual-Pol products is more significant Impact on Dual-Pol products is more significant KOUN: Dual-Pol KCRI: Single Pol

Attenuation and Dual Pol Products What has happened to ZDR? What has happened to ZDR? What are the consequences? What are the consequences?

Attenuation and Dual Pol Products What has happened to CC? What has happened to CC? What are the consequences? What are the consequences?

RPG Work Dual-Pol algorithms: lots of room to grow* Dual-Pol algorithms: lots of room to grow* – Knowledge base (research) central Oklahoma – Base data from RDA only recently mature enough for RPG testing – Greatest emphasis now is QPE MLDA HCA *Been there, done that: WSR-88D original development

Quantitative Precipitation Estimation Algorithm Benefits of Dual-Pol applied to rainfall estimation Benefits of Dual-Pol applied to rainfall estimation – Dual-Pol better at identifying ground clutter, biological scatterers, large hail, etc. Prevent these returns from being converted to rainfall Prevent these returns from being converted to rainfall Legacy Precipitation Processing System and products do not go away Legacy Precipitation Processing System and products do not go away

QPE Basics QPE is an RPG algorithm QPE & PPS have similarities & differences QPE supported by other Dual-Pol algorithms – – Hydrometeor Classification Algorithm (HCA) – – Melting Layer Detection Algorithm (MLDA)

QPE Similarities With Legacy PPS Accumulations start and stop based on coverage and intensity Accumulations start and stop based on coverage and intensity – Actual start and stop times will differ

QPE Similarities With Legacy PPS Exclusion zones Exclusion zones – Prevent returns (e.g. moving clutter) from being converted to rainfall – Zones defined separately for PPS and QPE Recommend same zones initially Recommend same zones initially

QPE Similarities With Legacy PPS Storm total accumulations reset at RPG Storm total accumulations reset at RPG

QPE Similarities With Legacy PPS Concept of Hybrid Scan same Concept of Hybrid Scan same – Find lowest unblocked elevation of valid precipitable return Common accumulation periods for PPS and QPE products Common accumulation periods for PPS and QPE products – One hour, storm total, user defined

QPE Differences From Legacy PPS HCA and MLDA input used to build QPE Hybrid Scan HCA and MLDA input used to build QPE Hybrid Scan – Prevent non-meteorological returns (e.g. clutter, biological) from conversion to rain rate – Determine best rain rate computation to use

How QPE Builds Hybrid Scan Each bin gets Hydroclass value from HCA Each bin gets Hydroclass value from HCA Biological Clutter Rain Heavy Rain Ice Crystals Wet Snow Big Drops Graupel Hail-Rain Unknown Dry Snow

How QPE Builds Hybrid Scan GC (clutter), UK (unkown) GC (clutter), UK (unkown) – Go up next tilt BI (biological), no echoes BI (biological), no echoes – Don’t search higher and set rain rate to 0.0 Remaining Hydroclass values are precipitable Remaining Hydroclass values are precipitable – Lots of details on this one…some other time!

QPE Differences From Legacy PPS QPE Hybrid Scan Hydroclass R(Z) R(Z,Z DR ) R(K DP ) PPS R(Z) Hybrid Scan Reflectivity QPE rain rate product every volume scan QPE rain rate product every volume scan

Why is QPE Work Going On NOW? Base data from RDA only recently (May!) mature enough for RPG testing Base data from RDA only recently (May!) mature enough for RPG testing – But wait! There’s more! LNAs switched out in July RDA work requires frequent shutdowns RDA work requires frequent shutdowns – QPE and PPS both require High quality base data High quality base data Appropriate clutter filtering Appropriate clutter filtering RDA stable and calibrated RDA stable and calibrated

QPE is an Algorithm Base Data Rules! Base Data Rules!

QPE Work Currently Underway Attenuation and QPE Attenuation and QPE Easy to identify in base data Easy to identify in base data

QPE Work Currently Underway QPE can show zero rain rates QPE can show zero rain rates – Attenuation correction for DP variables being worked

QPE Work Currently Underway R(KDP) performance looks good so far R(KDP) performance looks good so far R(Z,ZDR) performance R(Z,ZDR) performance – Significant underestimation of high efficiency (warm rain) rainfall – Underestimation similar to R(Z) QPE Hybrid Scan Hydroclass R(Z) R(Z,Z DR ) R(K DP )

QPE Work Currently Underway R(Z,ZDR) performance R(Z,ZDR) performance Warm rain event, flash flooding in OKC Warm rain event, flash flooding in OKC – We were lucky to discover this (warm rain in OK and KOUN was running) Gage: QPE: 4.40 PPS: 4.81

QPE Work Currently Underway Current version of R(Z,ZDR) based on large group of central OK rain events Current version of R(Z,ZDR) based on large group of central OK rain events – “Individual cases may vary” Solution requirement: no operator parameter changes Solution requirement: no operator parameter changes

Thank You You are an important part of this process You are an important part of this process