scholarly journals Supplementary material to "Coherent backscatter enhancement in bistatic Ku-/X-band radar observations of dry snow"

2021 ◽  
Author(s):  
Marcel Stefko ◽  
Silvan Leinss ◽  
Othmar Frey ◽  
Irena Hajnsek
Keyword(s):  
Radar Observations ◽  
X Band ◽  
Supplementary Material ◽  
Coherent Backscatter

Bistatic radar observations of the coherent backscatter opposition effect in dry snow

2021 ◽  
Author(s):  
Marcel Stefko ◽  
Silvan Leinss ◽  
Irena Hajnsek
Keyword(s):  
Mean Free Path ◽  
Radar System ◽  
Bistatic Radar ◽  
Snow Layer ◽  
Radar Observations ◽  
Opposition Effect ◽  
Snow Properties ◽  
X Band ◽  
Coherent Backscatter ◽  
Ku Band

<p>In this submission we report on observations of the coherent backscatter opposition effect (CBOE) in seasonal snow layers using bistatic radar, and the possible pathways towards estimation of snow properties from these radar observations.</p><p>Bistatic radar refers to a configuration where the transmitter and the receiver are not in the same location. From the point of view of the observed target, there thus exists a non-zero angular separation between  directions towards the transmitter and towards the receiver, referred to as the bistatic angle. The coherent backscatter opposition effect (CBOE) is a phenomenon that causes increased backscatter of coherent radiation at small bistatic angles (less than 1 degree) in refractive but non-absorbing disordered media (e.g. snow). It has been previously investigated to characterize surfaces of various water-ice covered Solar System bodies [1], however it has received comparatively little attention in Earth-focused observations, despite the well-known occurrence of significant volume scattering within snow and ice.</p><p>Scattering models of CBOE relate the shape of the intensity peak (width, height) to specific parameters of the random medium (grain size, mean free path, reflectivity) [2]. Measurements of the CBOE peak profile are thus a possible pathway towards improving the accuracy of estimates of these parameters, and those closely connected to them, such as the snow water equivalent (SWE).</p><p>We report on two separate observations of the CBOE-intensity peak in snow. We carried out ground-based observations using an experimental bistatic Ku-band radar system KAPRI [3], to observe the effect in a winter snow layer on top of the peak Rinerhorn in Davos, Switzerland. We also report on observations of backscatter enhancement in the accumulation zone of Aletsch glacier, using the spaceborne bistatic X-band synthetic aperture radar system TanDEM-X. Applying the aforementioned scattering models to the observations, we can estimate the mean free path of the scattered signal within the snow layer to be 10 cm at Ku-band, and 17 cm at X-band.</p><p>We believe that further study of CBOE in the context of Earth-focused observations of snow and ice opens new opportunities for development of quantitative models aiming to derive snow properties from bistatic radar observations.</p><p>REFERENCES</p><p>[1] Black et al. 2001: Icy Galilean Satellites: Modeling Radar Reflectivities as a Coherent Backscatter Effect. Icarus, 151(2), 167–180.<br>[2] Hapke et al. 1998: The Opposition Effect of the Moon: Coherent Backscatter and Shadow Hiding. Icarus, 133(1), 89–97.<br>[3] Baffelli et al. 2017: Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer. IEEE Transactions on Geoscience and Remote Sensing, 56(4), 2295–2311.</p>

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

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 Genesis, Maintenance and Demise of a Simulated Tornado and the Evolution of Its Preceding Descending Reflectivity Core (DRC)

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 236 ◽  
Author(s):  
Dan Yao ◽  
Zhiyong Meng ◽  
Ming Xue
Keyword(s):  
Cloud Model ◽  
Three Dimensional ◽  
Radiosonde Data ◽  
Phase Array ◽  
Bottom Up ◽  
Near Surface ◽  
Radar Observations ◽  
X Band ◽  
Homogeneous Background ◽  
Tornado Event

This study demonstrates the capability of a cloud model in simulating a real-world tornado using observed radiosonde data that define a homogeneous background. A reasonable simulation of a tornado event in Beijing, China, on 21 July 2012 is obtained. The simulation reveals the evolution of a descending reflectivity core (DRC) that has commonalities with radar observations, which retracts upward right before tornadogenesis. Tornadogenesis can be divided into three steps: the downward development of mesocyclone vortex, the upward development of tornado vortex, and the eventual downward development of condensation funnel cloud. This bottom-up development provides a numerical evidence for the growing support for a bottom-up, rapid tornadogenesis process as revealed by the state-of-the-art mobile X-band phase-array radar observations. The evolution of the simulated tornado features two replacement processes of three near-surface vortices coupled with the same midlevel updraft. The first replacement occurs during the intensification of the tornado before its maturity. The second replacement occurs during the tornado’s demise, when the connection between the midlevel mesocyclone and the near-surface vortex is cut off by a strong downdraft. This work shows the potential of idealized tornado simulations and three-dimensional illustrations in investigating the spiral nature and evolution of tornadoes.

Supplementary material to "Retrieving horizontally resolved wind fields using multi-static meteor radar observations"

2018 ◽  
Author(s):  
Gunter Stober ◽  
Jorge L. Chau ◽  
Juha Vierinen ◽  
Christoph Jacobi ◽  
Sven Wilhelm
Keyword(s):  
Meteor Radar ◽  
Wind Fields ◽  
Radar Observations ◽  
Supplementary Material

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.

scholarly journals Radar Applications in Northern Scotland (RAiNS)

2020 ◽  
Author(s):  
Ryan R Neely ◽  
Louise Parry ◽  
David Dufton ◽  
Lindsay Bennett ◽  
Chris Collier
Keyword(s):  
High Resolution ◽  
Weather Radar ◽  
Polarimetric Radar ◽  
Summer Period ◽  
Radar Observations ◽  
X Band ◽  
Precipitation Estimates ◽  
Radar Applications ◽  
Quantitative Precipitation Estimates ◽  
Hydrological Applications

AbstractThe Radar Applications in Northern Scotland (RAiNS) experiment took place from February to August 2016 near Inverness, Scotland. The campaign was motivated by the need to provide enhanced weather radar observations for hydrological applications for the Inverness region. Here we describe the campaign in detail and observations over the summer period of the campaign that show the improvements that high-resolution polarimetric radar observations may have on quantitative precipitation estimates in this region compared to concurrently generated operational radar quantitative precipitation estimates (QPE). We further provide suggestions of methods for generating QPE using dual-polarisation X-band radars in similar regions.

Sign in / Sign up

Export Citation Format

Share Document