# Presentation: 590278

## Evaluation of CASA (and other gap-filling) Radars

***Evaluation of CASA ******(and other gap-filling) Radars***

***Severe Weather Workshop for NWS Warning Decision Making -  11 July 2007***

- Kurt Hondl     DOC/NOAA/OAR       National Severe Storms Lab _[Kurt.Hondl@noaa.gov](mailto:Kurt.Hondl@noaa.gov)_

- Brenda Philips
- CASA Eng. Research Center
- U Mass, Amherst _[bphilips@ecs.umass.edu](mailto:bphilips@ecs.umass.edu)_

## Gap-Filling Radars

- Any radar that NOAA doesn’t control
- CASA
- FAA TDWR (and ARSR)
- Environment Canada radars
- TV station radars
- Mobile radars (SMART-R)

## Gap-Filling Radars

- Considerations
- Scan Strategy
- Data Quality / Filtering
- Data Resolution (time and space)
- Moments (reflectivity only, dual pol)
- Wavelength
- PRF (dual PRF)
- How do these considerations affect my decision making process?
- How do gap-filling radars change my warning products?

## What is CASA?

- National Science Foundation Engineering Research Center
- Academic, Government and Private Sector Partners
- NOAA is a CASA partner
- CASA’s Focus: New weather observation system paradigm based on low-power, low-cost networks of radars.
- Faculty, students and industry/practitioners work in a multi-disciplinary environment on real-world technology.
- Year 4 of a 10-year research project

## Radar System Comparison 

| CASA | WSR-88D |
| --- | --- |
| X-band (3cm), 25 kW, 1.8 deg beamwidth, Dual Pol | S-band (10cm), 750 kW, 1 deg beamwidth, Dual Pol upgrade coming |
| 40 km radar range, 50 m range gates | 230 km radar range, 250 m range gates |
| 1 deg azimuthal spacing | 1 deg azimuthal spacing (upgrade to 0.5 deg spacing next year) |
| Dual PRF(38 m/s Nyquist Velocity) |  |

- 8.0 deg

- 11.0 deg

- 20060815-222919

- 20060815-222924

## CASA System Architecture

- End users: NWS,
- Emergency Response,
- Researchers

**1. Radars** Scan atmosphere and send data to repository (initially centralized, later distributed)

**2.**** ****Weather Detection algorithms** run on data

- 3.  Detections  and other data are “posted” in **Feature Repository**

- 4. **Tasks ** are generated based on detections and **User Rules**

**5. Optimal Radar Scans **are configured to complete as many tasks as possible while maximizing data utility to users

***CASA System Architecture***

## Radar Scanning Strategy - DCAS

***Radar Scanning Strategy - DCAS***

_**Distributed Collaborative Adaptive Sensing**_**:  1 minute update consisting of a 20 sec. surveillance scan and 40 sec. targeted sector scans based on multiple user needs, feature detections, radar capabilities.**

**360 degree surveillance scans at 2 degrees.**

**Small squares are weather detections.  Larger polygons are potential tasks that could be scanned.**

**Sector scan. The number of lines indicate how many elevations are scanned**

## Slide 8

##  CASA Spring Experiment ‘07

- 9 April – 10 June
- Three, 3-week, IOPs
- Daily meeting to establish plan for day, evaluation of prior day’s results
- 24/7  operation during weather events
- Kick-off meeting March 30, mid term evaluation, final evaluation
- Evaluation in Hazardous Weather Testbed, pilot emergency mangers, CASA reseachers.

- Experiments will run in 2008 and 2009

## Experimental Warning Project Tasks

***Experimental Warning Project Tasks***

- Obtain NOAA input into the design of a new weather observation system
- Forecasters evaluate real time CASA data in test and case studies (May 8, April 10), complete evaluation
- What weather features do you see in CASA data that might help with severe weather warning decisions?
- What are the strengths                                             and weaknesses of                                             CASA’s technical                                            capabilities?

## Feedback on Weather Features seen in CASA data

- Mini Super Cells/Small Circulations
- Detailed Super Cell storm structure
- Hook Echo
- V-Notch
- Bow Echo
- Convergence/Divergence
- Rotation couplets: mesocyclonic, tornadic
- Lacking: Low reflectivity boundaries

## April 10, 2007 Elevated Super Cell

**CASA’s Adaptive Sector scanning at multiple elevations from 1 to 14 degrees, 40 sec. sector scan**

**NEXRAD Comparison**

**CASA High Resolution   Data**

**Ground Truth Verification by Val Castor’s NEWS9**

**April 10, 2007 Elevated Super Cell**

## Minco Mini-Supercell Tornado     May 8, ~11pm CDT

- 10:51 CDT

- © Patrick Marsh

## Feedback on Technology

**High resolution data** and strong gradients provide more detailed view of weather features: v-notch, bow echoes, downdrafts, appendages
**Lower troposphere** data shows mini-super cells, fine scale rotations.
**1 minute updates** provide more rapid confirmation of feature evolution
**2 degree, 360 degree** scans important for situational awareness
- Rapid **sector scans** at multiple elevations enables faster vertical analysis of storm structure, but...
- Scans not always in the right location, narrow sectors an issue

##  Narrow Sectors

**Issues:**
- Task Definition
- Trade Offs: sector width, update time, elevations

## Feedback on Technology

**Data quality** reflects early stage of system
**Minimum reflectivity threshold** of 20 dBZ hinders seeing boundaries
**Existing visualization** tools need to be enhanced to accommodate DCAS scanning.
- Merged data, navigating sector scans
- Decouple system heartbeat from visualization

***Needed: New Conceptual Models for Severe Warning Process for CASA data***
- Which fine scale rotations warrant a warning?
- What are the characteristics of super cell evolution in CASA data?
- Impact of 1 minute updates for resolving uncertainty

## Next Steps

- Analysis of storm features to begin to develop new conceptual models for warning: science/operations collaboration
- Development of training for HWT2008
- Modify systems for storm season 2008, 2009 based on feedback
- Data quality issues
-  Modify adaptive scanning
-  New visualization approaches
- Bring case studies to other forecast offices for feedback