CASA Update for MPAR Group David McLaughlin University of Massachusetts – Amherst V. Chandrasakar Colorado State University March 20, 2007 – OFCM/Silver Spring, MD

Three Key points 1.The disruptive technology CASA is pursuing is not limited to the lower troposphere. 2.Key technologies  Phased array technologies – CASA and partner Raytheon (this session)  Beam resource allocation  Multifunction inversion algorithms (eg, Dual Doppler). 3.CASA plans a substantial spring experiment to investigate & demonstrate many key system components & attributes and benefits to sensing, detecting, predicting, warning, and responding to hazardous weather events.

CASA: collaborative adaptive sensing of the atmosphere Critical gap Gap filler or lower-troposphere concept – works with lo-band complement 15 o

Network & System Trades 30km 22km 37km Low-level coverage Full volume coverage

CASA: collaborative adaptive sensing of the atmosphere 3 or 4 Face Phased Array 45° Full volume concept: all X-band

Project IP1: CASA’s Initial 4-Node Test Bed Users:  NWS Forecast Office  Oklahoma Emergency Managers Association  CASA researchers, themselves

WSR88D Attributes - Resolution; Coverage height; Update time; Multiple Doppler; multi-use

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3 0 /1.6 km4 0 /2 km 7 0 /3.6 km 9 0 /4.6 km 11 0 /5.7 km 14 0 /7.2 km

Dual-Doppler Analysis KSAO-KCYR winds KRSP-KCYR winds KRSP-KSAO winds

Multiple-Doppler Analysis

Overview of IP1 Spring 2007experiment Intense Operational Period (IOP) of data collection: April 9 – June 10 IOP 2007 operations include: - Daily meetings and weather briefings - Real-time, near-24 hour monitoring of the system - Hardware support in the field and on stand-by - Ground survey team on stand-by - Real-time assimilation of data into NWP (ARPS) models End-users include: - The National Weather Service - Local emergency managers - News9 (OKC media) - CASA Researchers - Private sector (e.g., Vieux & Associates)

Overview of IP1 Spring 2007 Data Collection IOP 2007 data collection summary: - Continuous, real-time DCAS mode. - Automated DCAS system driven by end-user rules and needs. - Real-time data dissemination to end-users via LDM. - Real-time visualization - Real-time attenuation-correction. - Dual-PRF signal processing. - All data archived permanently, stored on tape. Spring Experiment Leadership Team: V. Chandrasakar (CSU) – Lead J. Brotzge (OU) – Lead Forecaster B. Philips (UMass) – End User Integration Leader

For more details, see:

Low Cost, Low Power Radars Specifications:  1 m x 1 m X-band antennas  Mechanical scanning (2005)  Electronic scanning (2009)  2 degree pencil beam  Single and dual V & H polarization configurations  15+ degree elevation; 90 degree azimuth scan  10’s Watt average power  $50k target cost (in 2005 dollars, projected 10 years ahead) Deploying networks of these today Will deploy networks like this in 2009

Phase-Phase EScan Antennas 1.7 cm 1 m  ~3,000 T/R Modules performs electronic beam scanning in azimuth and elevation  Challenge: 100:1 cost reduction compared to today’s high-power military phased array radars - Raytheon Briefing-

Frequency-Phase EScan Antennas 1 m  Phase-steered in az direction (±45 deg or ±60 deg)  Freq-steered in elevation (0-56 degrees)  Requires excessive bandwidth (> 1 GHz) for frequency-scan. Deemed impractical.

Phase-tilt EScan Antenna 1 m  Phase-steered in az direction (±45 deg or ±60 deg)  Mechanical tilt in elevation (15 degrees) -11º to0º 0to+11º 12” deep

Dual Polarized Phase-Tilt EScan Array T/R MODULE BACKPLANE FEED ANTENNA DUAL POLARIZED LINEAR ARRAY ANTENNA 64 sticks dx=1.6cm, L=1 m 64 elements/stick dy=1.6 cm, L=1 m SITCK ANTENNA FEED Single Pol Prototype: 40 W panel $20k Spring ’08 Dual Pol Prototype: 10-40W $30-$50k Spring ‘09

Backup slides

Ground Clutter Filtering Rush Springs 30-Dec :03:47 UTC Reflectivity before filteringReflectivity after filtering Adaptive spectral ground clutter filtering (Chandra/CSU)

Rush Springs 30-Dec :03:47 UTC Velocity before filteringVelocity after filtering Ground Clutter Filtering

Dual-PRF waveform Velocity measurements greater than 30 m/s with dual-PRF Nyquist velocity of 38 m/s Range overlay suppression up to 93 km

Data from August 15 at 23:35:30 UTC 3 dual-Doppler syntheses –KRSP-KSAO –KRSP-KCYR –KCYR-KSAO All 3 radar scans start within 2 seconds of one another, so advection not really an issue All 3 radar scans were 360º at 2 elevation angles (3º and 4º) Dual-Doppler Synthesis

Dual-Polarized Attenuation Mitigation Before Attenuation CorrectionAfter Attenuation Correction