scholarly journals Mesoscale kinematics derived from X-band Doppler radar observations of convective versus stratiform precipitation and comparison with GPS radiosonde profiles

2015 ◽  
Vol 120 (22) ◽  
pp. 11,536-11,551 ◽  
Author(s):  
Sachin M. Deshpande ◽  
N. Dhangar ◽  
S. K. Das ◽  
M. C. R. Kalapureddy ◽  
K. Chakravarty ◽  
...  
Keyword(s):  
Doppler Radar ◽  
Radar Observations ◽  
X Band ◽  
Stratiform Precipitation ◽  
Gps Radiosonde

High-Temporal Resolution Polarimetric X-Band Doppler Radar Observations of the 20 May 2013 Moore, Oklahoma, Tornado

2015 ◽  
Vol 143 (7) ◽  
pp. 2711-2735 ◽  
Author(s):  
James M. Kurdzo ◽  
David J. Bodine ◽  
Boon Leng Cheong ◽  
Robert D. Palmer
Keyword(s):  
Temporal Resolution ◽  
Doppler Radar ◽  
Medical Center ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Radar Observations ◽  
University Of Oklahoma ◽  
X Band ◽  
Damage Indicators ◽  
Gust Front

Abstract On 20 May 2013, the cities of Newcastle, Oklahoma City, and Moore, Oklahoma, were impacted by a long-track violent tornado that was rated as an EF5 on the enhanced Fujita scale by the National Weather Service. Despite a relatively sustained long track, damage surveys revealed a number of small-scale damage indicators that hinted at storm-scale processes that occurred over short time periods. The University of Oklahoma (OU) Advanced Radar Research Center’s PX-1000 transportable, polarimetric, X-band weather radar was operating in a single-elevation PPI scanning strategy at the OU Westheimer airport throughout the duration of the tornado, collecting high spatial and temporal resolution polarimetric data every 20 s at ranges as close as 10 km and heights below 500 m AGL. This dataset contains the only known polarimetric radar observations of the Moore tornado at such high temporal resolution, providing the opportunity to analyze and study finescale phenomena occurring on rapid time scales. Analysis is presented of a series of debris ejections and rear-flank gust front surges that both preceded and followed a loop of the tornado as it weakened over the Moore Medical Center before rapidly accelerating and restrengthening to the east. The gust front structure, debris characteristics, and differential reflectivity arc breakdown are explored as evidence for a “failed occlusion” hypothesis. Observations are supported by rigorous hand analysis of critical storm attributes, including tornado track relative to the damage survey, sudden track shifts, and a directional debris ejection analysis. A conceptual description and illustration of the suspected failed occlusion process is provided, and its implications are discussed.

scholarly journals Bulk Hook Echo Raindrop Sizes Retrieved Using Mobile, Polarimetric Doppler Radar Observations

2015 ◽  
Vol 54 (2) ◽  
pp. 423-450 ◽  
Author(s):  
Michael M. French ◽  
Donald W. Burgess ◽  
Edward R. Mansell ◽  
Louis J. Wicker
Keyword(s):  
Doppler Radar ◽  
High Spatial Resolution ◽  
Life Cycles ◽  
Environmental Data ◽  
Size Distributions ◽  
Small Drop ◽  
Large Drop ◽  
Radar Observations ◽  
X Band ◽  
Drop Size Distributions

AbstractPolarimetric radar observations obtained by the NOAA/National Severe Storms Laboratory mobile, X-band, dual-polarization radar (NOXP) are used to investigate “hook echo” precipitation properties in several tornadic and nontornadic supercells. Hook echo drop size distributions (DSDs) were estimated using NOXP data obtained from 2009 to 2012, including during the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2). Differences between tornadic and nontornadic hook echo DSDs are explored, and comparisons are made with previous observations of estimated hook echo DSDs made from stationary S- and C-band Doppler radars. Tornadic hook echoes consistently contain radar gates that are characterized by small raindrops; nontornadic hook echoes are mixed between those that have some small-drop gates and those that have almost no small-drop gates. In addition, the spatial distribution of DSDs was estimated using the high-spatial-resolution data afforded by NOXP. A unique polarimetric signature, an area of relatively low values of differential radar reflectivity factor ZDR south and east of the tornado, is observed in many of the tornadic cases. Also, because most data were obtained using 2-min volumetric updates, the evolution of approximated hook echo precipitation properties was studied during parts of the life cycles of three tornadoes. In one case, there is a large decrease in the percentage of large-raindrop gates and an increase in the percentage of small-raindrop gates in the minutes leading up to tornado formation. The percentage of large-drop gates generally increases prior to and during tornado dissipation. Near-storm environmental data are used to put forth possible relationships between bulk hook echo DSDs and tornado production and life cycle.

Preliminary Results of Weather Radar Observations of Sakurajima Volcanic Smoke

2016 ◽  
Vol 11 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Masayuki Maki ◽  
◽  
Masato Iguchi ◽  
Takeshi Maesaka ◽  
Takahiro Miwa ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Doppler Radar ◽  
Three Dimensional ◽  
Weather Radar ◽  
Fall Velocity ◽  
Radar Observations ◽  
Preliminary Results ◽  
Ash Fall ◽  
X Band ◽  
Observation Instruments

Preliminary results of quantitative analysis of volcanic ash clouds observed over the Sakurajima volcano in Kagoshima, Japan, were obtained by using weather radar and surface instruments. The Ka-band Doppler radar observations showed the inner structure of a volcanic ash column every two minutes after an eruption. Operational X-band polarimetric radar provides information on three-dimensional ash fall amount distribution. The terminal fall velocity of ash particles was studied by using optical disdrometers, together with the main specifications of observation instruments.

scholarly journals Mobile, Phased-Array, Doppler Radar Observations of Tornadoes at X Band

2014 ◽  
Vol 142 (3) ◽  
pp. 1010-1036 ◽  
Author(s):  
Michael M. French ◽  
Howard B. Bluestein ◽  
Ivan PopStefanija ◽  
Chad A. Baldi ◽  
Robert T. Bluth
Keyword(s):  
Conceptual Model ◽  
Phased Array ◽  
Doppler Radar ◽  
Weather Radar ◽  
Volumetric Data ◽  
Radar Observations ◽  
X Band

Abstract A mobile, phased-array Doppler radar, the Mobile Weather Radar, 2005 X-band, Phased Array (MWR-05XP), has been used since 2007 to obtain data in supercells and tornadoes. Rapidly updating, volumetric data of tornadic vortex signatures (TVSs) associated with four tornadoes are used to investigate the time–height evolution of TVS intensity, position, and dissipation up through storm midlevels. Both TVS intensity and position were highly variable in time and height even during tornado mature phases. In one case, a TVS associated with a tornado dissipated aloft and a second TVS formed shortly thereafter while there was one continuous TVS near the ground. In a second case, the TVS associated with a long-lived, violent tornado merged with a second TVS (likely a second cyclonic tornado) causing the original TVS to strengthen. TVS dissipation occurred first at a height of ~1.5 km AGL and then at progressively higher levels in two cases; TVS dissipation occurred last in the lowest 1 km in three cases examined. Possible explanations are provided for the unsteady nature of TVS intensity and a conceptual model is presented for the initial dissipation of TVSs at ~1.5 km AGL.

The Multiple-Vortex Structure of the El Reno, Oklahoma, Tornado on 31 May 2013

2018 ◽  
Vol 146 (8) ◽  
pp. 2483-2502 ◽  
Author(s):  
Howard B. Bluestein ◽  
Kyle J. Thiem ◽  
Jeffrey C. Snyder ◽  
Jana B. Houser
Keyword(s):  
Doppler Radar ◽  
Radar Data ◽  
Rapid Scan ◽  
X Band ◽  
Close Range ◽  
Formation And Evolution ◽  
Using Data ◽  
Secondary Vortices ◽  
The Right ◽  
Gust Front

Abstract This study documents the formation and evolution of secondary vortices associated within a large, violent tornado in Oklahoma based on data from a close-range, mobile, polarimetric, rapid-scan, X-band Doppler radar. Secondary vortices were tracked relative to the parent circulation using data collected every 2 s. It was found that most long-lived vortices (those that could be tracked for ≥15 s) formed within the radius of maximum wind (RMW), mainly in the left-rear quadrant (with respect to parent tornado motion), passing around the center of the parent tornado and dissipating closer to the center in the right-forward and left-forward quadrants. Some secondary vortices persisted for at least 1 min. When a Burgers–Rott vortex is fit to the Doppler radar data, and the vortex is assumed to be axisymmetric, the secondary vortices propagated slowly against the mean azimuthal flow; if the vortex is not assumed to be axisymmetric as a result of a strong rear-flank gust front on one side of it, then the secondary vortices moved along approximately with the wind.

Rain-induced characteristics in C- and X-band synthetic aperture radar observations of tropical cyclones

2021 ◽  
Vol 12 (6) ◽  
pp. 573-584
Author(s):  
Xinzhe Yuan ◽  
Weizeng Shao ◽  
Bing Han ◽  
Xiaochen Wang ◽  
Xiaoqing Wang ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Tropical Cyclones ◽  
Synthetic Aperture ◽  
Radar Observations ◽  
X Band ◽  
Aperture Radar
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