# Presentation: 502457

## Radar QPE Working Group

*Moderator:*  **Dan Berkowitz**,
- Applications Branch
- Radar Operations Center

## Radar QPE Working Group Objectives

- Determine priorities for (Level II) base data improvement
- Determine priorities for (Level III) products
- Recommend improvements to National Mosaic Multisensor QPE (NMQ) for “Next Generation QPE” (Q2)
- Create a working group to develop required OSI Process documents with respect to radar improvements

## Uncertainties in Radar Precip. Estimation (abbreviated list)

- Complete or partial beam blockage
- Beam propagation path – height of sample
- Mixed precipitation types **(hail, rain, and/or snow)**
- Beam not filled with precipitation
- Evaporation near the ground
- Detection of non-meteorological targets (**ground, birds, bugs, **etc.)
- Displacement of radar sample relative to a ground location (rain gauge) due to wind shear
***It is expected that some of these problems will be rectified by dual polarization radar.***

## 1. Priorities for Base Data Improvement

- Calibration problems –
***We recommend WSR-88D Hotline be proactive at monitoring systems using the Reflectivity Comparison tool.  Even though this support may be limited to 7 a.m. to 7 p.m. Central Time on weekdays (when meteorologists are on duty), this should be done routinely.***
- Clutter management problems
***This is an ongoing training issue.***

## 1. Priorities for Base Data Improvement (cont’d)

- Scan strategies or volume coverage patterns
***New VCPs with lower elevation angles are needed for:***
***Mountain-top radar locations***
***Detection of snowfall at numerous locations***
- Ground clutter mitigation at RDA
***Research is needed to determine value of GMAP applied to fuzzy logic-identified AP clutter (NCAR-proposed Clutter Filter Decision Support). ***
***Research is needed to determine quality of dual polarization clutter mitigation to see if NCAR software adds any value.***

## 2. Priorities for RPG-created Products

- Probabilistic QPE products
***PQPE could be provided for educated users but only after deterministic methods are improved.  PQPE should not replace deterministic QPE products.***
- Snowfall (digital snowfall accumulation)
***A digital snowfall product is needed by RFCs.***
- Automated R(Zh) selection *(a.k.a. Z-R or Z/R relationship) *and/or MXPRA selection
***This is a good idea but ***_***needs research***_*** to determine when each relationship should be used.  Environmental data can come from soundings, the RUC model, and from an operator.***

## 2. Priorities for RPG-created Products (cont’d)

- Guidance for PPS Adaptable Parameters
- 	(CLUTTHRESH, RAINZ, RAINA, exclusion zones (for wind farms, highways, industrial plumes), and when it is good/bad to apply Gauge/Radar Mean Field Bias)
***There is an ongoing need for training on these parameters.  No software changes are needed.***

## 3. Suggested NMQ Improvements(with respect to radar products)

- Automated R(Zh) selection *(a.k.a. Z-R or Z/R relationship)*
***This is a good idea but ***_***needs research***_*** to determine when each relationship should be used.  Environmental data can come from soundings, the RUC model, and from an operator.***
- Bias application
***We like the ability to apply sectorized, local bias.  As with MPE-generated bias, users should know the source(s) of the bias calculation (i.e., the number and location of gauge-radar pairs).***

## 4. Operations and Services Improvement (OSI) Process

- Volunteers are needed to help prepare
- Statement of Need (SON)
- Concept of Operations (ConOps)
- Business Case Analysis
***So far, we have gotten no-one (except myself).  Are ******you****** interested?  Please let me know.***