THE NEW RADAR FOR AMERICA’S SPACE PROGRAM IN FLORIDA:SCAN STRATEGY DESIGN

William P. Roeder David A. Short 45th Weather Squadron ENSCO, Inc. Patrick AFB, FL Cocoa Beach, FL

Scan Strategy for New Radar Optimized for 45 WS Mission

Requirements for New Scan Strategy

Requirement Reason Solution

Volume Scan 3 min ( 2.5 min desired)

Rapidly Changing Thunderstorms in Florida in Summer

13 Beam Angles(more angles = longer scan)

(2.65 min volume scan)

Maximum beam gap 2,250 ft from +5C -2 to ‑20C +2 mean heights within 5 nmi of launch pads (< 1,500 ft desired)

Evaluate Lightning Launch Commit Criteria (LLCC)

(especially Thick Cloud rule)See Beam Angles

Maximum beam gap 2,250 ft from +0C -2 to ‑20C +2 mean heights within 10 nmi of CCAFS/KSC (< 1,500 ft desired)

Lightning Watches and Warnings See Beam Angles

Outstanding Coverage of Boundary Layer within 25 nmi of the Radar

• Detect Low-Level Boundaries

• Detect Low-Level VorticesSee Beam Angles

Excellent Coverage from 25-40 Kft (up to 50 Kft desired)

Evaluate Lightning LCC(especially Anvil Cloud rules)

See Beam Angles

Reduce Cone Of Silence Proper Tracking of Thunderstorm

Behavior when they Approach CCAFS/KSC from Southwest

See Beam Angles

Beam Gaps Independent of Range is Desired

Easier Analysis of Radar DataNot Met due to

Higher Priority Needs

Good Combination of Maximum Unambiguous Doppler Velocity and Maximum Range

• Detect Severe Weather

• Detect Approaching Weather with Enough Lead-Time

Dual PRF = 533/800 Hz(Max Range = 152 nmi,Max Velocity = 21 kt)

(reset from 800/1200 Hz to avoid multi-trip echo)

Good Pulse Power Mitigate C-Band Attenuation Pulse Width = 2.0 s(longer PW = more power)

Good Data Quality Proper Analysis of Weather 24 Samples per Pulse

Scan Strategy Design (designed by Applied Meteorology Unit)

No. Angle Purpose

1 0.2° Detect Low-Level Boundaries

2 1.2° • Detect Low-Level Boundaries

• Detect Low-Level Vortices3 2.2°

4 4.0° • High Vertical Resolution +5°C to -20°C ±2 for Lightning Launch Commit Criteria (LLCC) Evaluation

• High Vertical Resolution +0°C to -20°C ±2 for Lightning Prediction

• Detect Convective Cloud Tops and Anvil Clouds for LLCC Evaluation (beam angles 6-11, also beam angle 12 below)

5 5.7°

6 7.3°

7 8.9°

8 10.6°

9 12.5°

10 14.5°

11 17.6°

12 22.3° Detect Convective Cloud Tops and Anvil Clouds for LLCC Evaluation (also beam angles 6-11 above)

13 28.3° Reduce Cone Of Silence