scholarly journals Review of “The TRIple-frequency and Polarimetric radar Experiment for improving process observation of winter precipitation”

2019 ◽  
Author(s):  
Anonymous
Keyword(s):  
Winter Precipitation ◽  
Polarimetric Radar ◽  
Triple Frequency ◽  
Process Observation

scholarly journals The TRIple-frequency and Polarimetric radar Experiment for improving process observation of winter precipitation

2018 ◽  
Author(s):  
José Dias Neto ◽  
Stefan Kneifel ◽  
Davide Ori ◽  
Silke Trömel ◽  
Jan Handwerker ◽  
...  
Keyword(s):  
Winter Season ◽  
Winter Precipitation ◽  
Doppler Velocity ◽  
Depolarization Ratio ◽  
Time Duration ◽  
Frequency Space ◽  
Triple Frequency ◽  
Linear Depolarization Ratio ◽  
Process Observation ◽  
Processing Steps

Abstract. This study describes a two-months dataset of ground-based triple-frequency (X, Ka, and W-Band) Doppler cloud radar observations during the winter season obtained at the Jülich ObservatorY for Cloud Evolution core facility (JOYCE-CF), Germany. All relevant post-processing steps, such as re-gridding, offset and attenuation correction as well as quality flagging are described. The dataset contains all information needed to recover data at intermediate processing steps for user-specific applications and corrections (DOI: https://doi.org/10.5281/zenodo.1405539). The rather long time duration of the dataset allowed for a statistical analysis, which we focused on the ice and snow part of the cloud. The reflectivity differences quantified by dual-wavelength ratios revealed temperature regimes, where aggregation seems to be triggered. Overall, the aggregation signatures found in the triple-frequency space agree with and corroborate conclusions from previous studies. Combining the information from reflectivity information with mean Doppler velocity and linear depolarization ratio, enables us to distinguish signatures of rimed particles and melting snowflakes; while the riming signatures agree well with results from previous studies, we find very strong aggregation signatures close to the melting layer, which have not been reported before. Mean Doppler velocity and the linear depolarization ratio have been used to separate the extreme aggregation signature from the triple-frequency characteristics of melting particles.

scholarly journals Accurate Characterization of Winter Precipitation Using Multi-Angle Snowflake Camera, Visual Hull, Advanced Scattering Methods and Polarimetric Radar

Atmosphere ◽  
2016 ◽  
Vol 7 (6) ◽  
pp. 81 ◽  
Author(s):  
Branislav Notaroš ◽  
Viswanathan Bringi ◽  
Cameron Kleinkort ◽  
Patrick Kennedy ◽  
Gwo-Jong Huang ◽  
...  
Keyword(s):  
Winter Precipitation ◽  
Visual Hull ◽  
Polarimetric Radar

scholarly journals The TRIple-frequency and Polarimetric radar Experiment for improving process observations of winter precipitation

2019 ◽  
Vol 11 (2) ◽  
pp. 845-863 ◽  
Author(s):  
José Dias Neto ◽  
Stefan Kneifel ◽  
Davide Ori ◽  
Silke Trömel ◽  
Jan Handwerker ◽  
...  
Keyword(s):  
Doppler Radar ◽  
Winter Season ◽  
Winter Precipitation ◽  
Doppler Velocity ◽  
Depolarization Ratio ◽  
Frequency Space ◽  
Triple Frequency ◽  
Temperature Regimes ◽  
Linear Depolarization Ratio ◽  
Processing Steps

Abstract. This paper describes a 2-month dataset of ground-based triple-frequency (X, Ka, and W band) Doppler radar observations during the winter season obtained at the Jülich ObservatorY for Cloud Evolution Core Facility (JOYCE-CF), Germany. All relevant post-processing steps, such as re-gridding and offset and attenuation correction, as well as quality flagging, are described. The dataset contains all necessary information required to recover data at intermediate processing steps for user-specific applications and corrections (https://doi.org/10.5281/zenodo.1341389; Dias Neto et al., 2019). The large number of ice clouds included in the dataset allows for a first statistical analysis of their multifrequency radar signatures. The reflectivity differences quantified by dual-wavelength ratios (DWRs) reveal temperature regimes where aggregation seems to be triggered. Overall, the aggregation signatures found in the triple-frequency space agree with and corroborate conclusions from previous studies. The combination of DWRs with mean Doppler velocity and linear depolarization ratio enables us to distinguish signatures of rimed particles and melting snowflakes. The riming signatures in the DWRs agree well with results found in previous triple-frequency studies. Close to the melting layer, however, we find very large DWRs (up to 20 dB), which have not been reported before. A combined analysis of these extreme DWR with mean Doppler velocity and a linear depolarization ratio allows this signature to be separated, which is most likely related to strong aggregation, from the triple-frequency characteristics of melting particles.

Winter Precipitation Microphysics Characterized by Polarimetric Radar and Video Disdrometer Observations in Central Oklahoma

2011 ◽  
Vol 50 (7) ◽  
pp. 1558-1570 ◽  
Author(s):  
Guifu Zhang ◽  
Sean Luchs ◽  
Alexander Ryzhkov ◽  
Ming Xue ◽  
Lily Ryzhkova ◽  
...  
Keyword(s):  
Prediction Models ◽  
Weather Prediction ◽  
Winter Season ◽  
Winter Precipitation ◽  
Polarimetric Radar ◽  
Particle Size Distributions ◽  
Physical Processes ◽  
Polarimetric Weather Radar ◽  
Numerical Weather Prediction Models ◽  
Precipitation Events

AbstractThe study of precipitation in different phases is important to understanding the physical processes that occur in storms, as well as to improving their representation in numerical weather prediction models. A 2D video disdrometer was deployed about 30 km from a polarimetric weather radar in Norman, Oklahoma, (KOUN) to observe winter precipitation events during the 2006/07 winter season. These events contained periods of rain, snow, and mixed-phase precipitation. Five-minute particle size distributions were generated from the disdrometer data and fitted to a gamma distribution; polarimetric radar variables were also calculated for comparison with KOUN data. It is found that snow density adjustment improves the comparison substantially, indicating the importance of accounting for the density variability in representing model microphysics.

scholarly journals Analysis of the microphysical properties of snowfall using scanning polarimetric and vertically pointing multi-frequency Doppler radars

2021 ◽  
Vol 14 (7) ◽  
pp. 4893-4913
Author(s):  
Mariko Oue ◽  
Pavlos Kollias ◽  
Sergey Y. Matrosov ◽  
Alessandro Battaglia ◽  
Alexander V. Ryzhkov
Keyword(s):  
Early Stage ◽  
Particle Growth ◽  
Particle Identification ◽  
Joint Analysis ◽  
Doppler Velocity ◽  
Polarimetric Radar ◽  
Dual Frequency ◽  
Growth Processes ◽  
Ka Band ◽  
Triple Frequency

Abstract. Radar dual-wavelength ratio (DWR) measurements from the Stony Brook Radar Observatory Ka-band scanning polarimetric radar (KASPR, 35 GHz), a W-band profiling radar (94 GHz), and a next-generation K-band (24 GHz) micro rain radar (MRRPro) were exploited for ice particle identification using triple-frequency approaches. The results indicated that two of the radar frequencies (K and Ka band) are not sufficiently separated; thus, the triple-frequency radar approaches had limited success. On the other hand, a joint analysis of DWR, mean Doppler velocity (MDV), and polarimetric radar variables indicated potential in identifying ice particle types and distinguishing among different ice growth processes and even in revealing additional microphysical details. We investigated all DWR pairs in conjunction with MDV from the KASPR profiling measurements and differential reflectivity (ZDR) and specific differential phase (KDP) from the KASPR quasi-vertical profiles. The DWR-versus-MDV diagrams coupled with the polarimetric observables exhibited distinct separations of particle populations attributed to different rime degrees and particle growth processes. In fallstreaks, the 35–94 GHz DWR pair increased with the magnitude of MDV corresponding to the scattering calculations for aggregates with lower degrees of riming. The DWR values further increased at lower altitudes while ZDR slightly decreased, indicating further aggregation. Particle populations with higher rime degrees had a similar increase in DWR but a 1–1.5 m s−1 larger magnitude of MDV and rapid decreases in KDP and ZDR. The analysis also depicted the early stage of riming where ZDR increased with the MDV magnitude collocated with small increases in DWR. This approach will improve quantitative estimations of snow amount and microphysical quantities such as rime mass fraction. The study suggests that triple-frequency measurements are not always necessary for in-depth ice microphysical studies and that dual-frequency polarimetric and Doppler measurements can successfully be used to gain insights into ice hydrometeor microphysics.

Characterizing secondary ice production events in mixed-phase clouds using ground-based polarimetric radar

2020 ◽  
Author(s):  
Nicholas Kedzuf ◽  
J. Christine Chiu ◽  
Venkatachalam Chandrasekar ◽  
Christopher Westbrook
Keyword(s):  
Doppler Radar ◽  
Radar Data ◽  
Number Concentration ◽  
Mixed Phase ◽  
Polarimetric Radar ◽  
Triple Frequency ◽  
Ice Production ◽  
The Uk ◽  
Cloud Ice ◽  
Mixed Phase Clouds

<p>Secondary ice production processes are widely proposed as the pathway by which observed cloud ice number concentration can markedly exceed what is expected from primary ice nucleation alone. These processes play a critical, yet poorly constrained, role in the lifecycle of mixed-phase clouds. Presently, main constraints on secondary ice production come from airborne observations, but the transiency of such observations makes it difficult to paint a complete picture of these processes. Here, we develop a novel method for retrieving ice number concentration in a Lagrangian reference frame, allowing us to unearth information not accessible from existing aircraft observations. Our retrieval method employs an iterative ensemble approach, advanced ice crystal models, and the traditional suite of polarimetric radar observables. We will present examples from the Atmospheric Radiation Measurement (ARM) program Mobile Facility deployment in Finland and evaluations against in-situ observations from the UK Parameterizing Ice Clouds using Airborne obServationS and triple-frequency dOppler radar data (PICASSO) field campaign. We will also present a climatology of cloud ice number concentration from the Finland campaign, shedding light on the spatiotemporal evolution, process rates, and trigger requirements of secondary ice production events.</p>

scholarly journals Winter Precipitation Liquid–Ice Phase Transitions Revealed with Polarimetric Radar and 2DVD Observations in Central Oklahoma

2017 ◽  
Vol 56 (5) ◽  
pp. 1345-1363 ◽  
Author(s):  
Petar Bukovčić ◽  
Dušan Zrnić ◽  
Guifu Zhang
Keyword(s):  
Radar Data ◽  
Winter Precipitation ◽  
Precipitation Event ◽  
Vertical Profiles ◽  
Polarimetric Radar ◽  
Phase Precipitation ◽  
Local Enhancement ◽  
Model Simulations ◽  
Differential Reflectivity ◽  
Ice Phase

AbstractObservations and analysis of an ice–liquid phase precipitation event, collected with an S-band polarimetric KOUN radar and a two-dimensional video disdrometer (2DVD) in central Oklahoma on 20 January 2007, are presented. Using the disdrometer measurements, precipitation is classified either as ice pellets or rain/freezing rain. The disdrometer observations showed fast-falling and slow-falling particles of similar size. The vast majority (>99%) were fast falling with observed velocities close to those of raindrops with similar sizes. In contrast to the smaller particles (<1 mm in diameter), bigger ice pellets (>1.5 mm) were relatively easy to distinguish because their shapes differ from the raindrops. The ice pellets were challenging to detect by looking at conventional polarimetric radar data because of the localized and patchy nature of the ice phase and their occurrence close to the ground. Previously published findings referred to cases in which ice pellet areas were centered on the radar location and showed a ringlike structure of enhanced differential reflectivity ZDR and reduced copolar correlation coefficient ρhv and horizontal reflectivity ZH in PPI images. In this study, a new, unconventional way of looking at polarimetric radar data is introduced: slanted vertical profiles (SVPs) at low (0°–1°) radar elevations. From the analysis of the localized and patchy structures using SVPs, the polarimetric refreezing signature, reflected in local enhancement in ZDR and reduction in ZH and ρhv, became much more evident. Model simulations of sequential drop freezing using Marshall–Palmer DSDs along with the observations suggest that preferential freezing of small drops may be responsible for the refreezing polarimetric signature, as suggested in previous studies.

scholarly journals Combination Analysis of Multi-Wavelength, Multi-Parameter Radar Measurements for Snowfall

2021 ◽  
Author(s):  
Mariko Oue ◽  
Pavlos Kollias ◽  
Sergey Y. Matrosov ◽  
Alessandro Battaglia ◽  
Alexander V. Ryzhkov
Keyword(s):  
Early Stage ◽  
Particle Growth ◽  
Particle Identification ◽  
Joint Analysis ◽  
Doppler Velocity ◽  
Polarimetric Radar ◽  
Growth Processes ◽  
Ka Band ◽  
Triple Frequency ◽  
W Band

Abstract. Radar dual wavelength ratio (DWR) measurements from the Stony Brook Radar Observatory Ka-band Scanning Polarimetric Radar (KASPR, 35 GHz), a profiling W-band (94 GHz) and a next generation K-band (24-GHz) Micro Rain Radar (MRRPro) were exploited for ice particle identification using triple frequency approaches. The results indicated that two of the radar frequencies (K- and Ka-band) are not sufficiently separated, thus, the triple radar frequency approaches had limited success. On the other hand, a joint analysis of DWR, mean vertical Doppler velocity (MDV), and polarimetric radar variables indicated potential in identifying ice particle types and distinguishing among different ice growth processes and even in revealing additional microphysical details.We investigated all DWR pairs in conjunction with MDV from the KASPR profiling measurements and differential reflectivity (ZDR) and specific differential phase (KDP) from the KASPR quasi-vertical profiles. The DWR-versus-MDV diagrams coupled with the polarimetric observables exhibited distinct separations of particle populations attributed to different rime degrees and particle growth processes. In fallstreaks, the 35–94 GHz DWR pair increased with the magnitude of MDV corresponding to the scattering calculations for aggregates with lower degrees of riming. The DWR values further increased at lower altitudes while ZDR slightly decreased, indicating further aggregation. Particle populations with higher rime degrees had a similar increase of DWR, but the 1–1.5 m s−1 larger magnitude of MDV and rapid decreases in KDP and ZDR. The analysis also depicted the early stage of riming where ZDR increased with the MDV magnitude collocated with small increases of DWR. This approach will improve quantitative estimations of snow amount and microphysical quantities such as rime mass fraction.

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