DOW7

1. Tribune, KS: 25 May 2010 RAPID-SCAN DOW RADAR OBSERVATIONS OF TORNADOES DURING VORTEX2 2009 and 2010 Joshua Wurman, Karen Kosiba, Paul C. Robinson Center for Severe Weather Research Rapid-Scan DOW6 Rapid-Scan DOW6 DOW7 DOW7 DOW6 Rapid-Scan Rapid-Scan DOW6 DOW7 DOW7 Rapid-Scan DOW is an NSF facilityDOWs are supported by NSF-ATM-0734001 and -0966095 and -0946926 Analysis supported by NSF-ATM-0801041 VORTEX2 supported by SPO grant NSF-ATM-0724318 and others Observations: Green = DOW7 radius and locations Maroon = DOW6 Blue = Rapid-Scan Observations: Green = DOW7 radius and locations Maroon = DOW6 Blue = Rapid-Scan Rapid oscillations resolved by Rapid-Scan, not by DOW-7 Bovina, CO: 11 June 2010 DOW 6 at 0112:51 UTC Booker, TX: 13 June 2010 9730 MHz 6.2o Two Simultaneous Tornadoes Rapid-Scan DOW at 0112:55 UTC Analysis supported by NSF-ATM -0801041 DOWs supported by NSF-ATM-0734001 and -0966095 and -0946926 VORTEX2 supported by SPO grant NSF-ATM-0724318 and others Right: Map detailing observations obtained by the Rapid-Scan DOW (blue) and DOW 7 (green). Circles denote radius of maximum winds observed by respective radars. Note the additional observations available from the Rapid-Scan DOW. Below: An example scan through the tornado by the Rapid-Scan DOW. Allfour elevations were taken at 23:40:39 UTC. Note the lack of the reflectivity eye at the four degree elevation scan. 9649 MHz 5.3o Rapid-Scan Observations DOW7 Observations Rapid-Scan Observations DOW7 Observations DOW-Rapid-Scan Comparison (Above):Comparisons of DOW-measured Doppler velocity (left) and radar reflectivity (right) as observed by DOW 6 (top) and Rapid-scan DOW (bottom), indicating good agreement on both large-scale and fine-scale (black circles) circulations. 1.3 ° 1.3 ° 0.5 ° Allscans taken at 23:40:39 UTC 0.5 ° 9562 MHz 4.0o • Six simultaneous elevations scanned • Full volume updates every seven seconds. • 50 or 25-meter gate spacing • 0.8 – 0.9 degree beam width • 4D resolution @ 2 km • 28 m x 30 m x 25 m x 7 s = 150,000 m3s 9478 MHz 3.0o DOW7 13 km south DOW7 13 km south Combined DOW7 and Rapid-Scan measurements: Captured genesis and demise 9354 MHz 1.3o 3.0 ° 3.0 ° 4.0 ° 4.0 ° 9310 MHz 0.5o Simultaneous Scans at Multi-Levels Above: DOW-measured Doppler velocity (left) and radar reflectivity (right) from each channel of the rapid-scan radar. Time of observation was 01:09:20 GMT Above: An example Rapid-Scan observation of velocity (left) and reflectivity (right) at a single elevation angle. The structure of the inner debris ring is well captured. Left: Delta-V as measured by DOW 7 (green) and Rapid-Scan DOW (red), capturing tornado genesis, intensification and demise. Above: The entire evolution of the Booker, TX tornado was captured by the DOW radar network. 1-2 Minute Oscillations Observed Seven-second observations of the Rapid-Scan DOW delta-V at three different elevations (far left). An FFT analysis of channel 4 reveals periodic oscillations in tornado intensity approximately every 1.1-1.8 minutes (center). These ~ 1 minute oscillations are not captured by the 1-minute DOW7 observations (right). Goshen Co., WY: 5 June 2009 Left: Axisymmetric radial and tangential wind profiles derived from the Rapid-Scan DOW using the GBVTD technique at 130 m AGL. Divergence is present inside the radius of maximum winds, while farther outside the radius of maximum winds weak inflow is observed. GBVTD Reveals Outflow Inside RMW:Ground-based velocity track display (GBVTD) analyses derived from 7-second Rapid Scan DOW observations (above). Color contours indicate tangential winds and vectors denote the secondary circulation. 2214:07 2214:07 2214:14 2214:21 2214:28 2214:35 2214:42 2214:49 Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan DOW 7 Rapid-Scan Rapid-Scan a b 2214:57 2214:57 2215:04 2215:11 2215:18 2215:25 2215:32 2215:39 DOW 7 Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Rapid-Scan Reveals Fast Evolution: (Above) Evolution of the velocity (left, in images) and reflectivity (right, in images) from 2214:07-2115:39 UTC. DOW 7 (outlined in magenta) completes a volume approximately every one minute , whereas the Rapid-scan DOW (outlined in blue) completes a volume every seven seconds. Images are shown for the lowest elevation scan for both radars. Note the rapid evolution of the tornado that occurs on timescales of < one minute.