Classification of particles in stratiform clouds using the 33 and 95 GHz polarimetric cloud profiling radar system (CPRS)

Lohmeier, S.P.; Sekelsky, S.M.; Firda, J.M.; Sadowy, G.; McIntosh, R.E.

doi:10.1109/36.563264

Cited by 28 publications

(13 citation statements)

References 35 publications

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“…Values of SLDR measured vertically in rain, in the melting layer, in ice areas, and in regions dominated by scattering from insects are consistent with direct measurements of LDR (Lohmeier et al, 1997;Di Girolamo et al, 2012;Görs-dorf et al, 2015). Values of ρ CX for meteorological scatterers are 0 as it follows from theoretical considerations (Myagkov et al, 2015).…”

supporting

confidence: 85%

“…The plates were mounted into the waveguide system of a ground-based Ka-band radar, operated by the Wave Propagation Laboratory of the National Oceanic and Atmospheric Administration. A number of studies present polarimetric measurements of winter clouds taken by airborne (Galloway et al, 1997;Wolde and Vali, 2001) and groundbased cloud radars (Pazmany et al, 1994;Lohmeier et al, 1997;Reinking et al, 2002). Often such measurements were compared with the microphysical properties of the ice crystals observed in situ with aircraft or on ground.…”

Section: A Myagkov Et Al: Cloud Radar With Hybrid Mode Towards Estimentioning

confidence: 99%

“…The corresponding operation mode is denoted as the linear depolarization ratio mode (LDR mode). Often, LDR measurements taken with vertically pointed cloud radars are used for clutter filtering (Görsdorf et al, 2015) and a reliable detection of the melting layer (Lohmeier et al, 1997). At the same time the applicability of the LDR mode for the shape estimation is limited because of its high sensitivity to the orientation of cloud particles (Matrosov et al, 2001).…”

Section: Mira-35 With Hybrid Modementioning

confidence: 99%

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Cloud radar with hybrid mode towards estimation of shape and orientation of ice crystals

et al. 2016

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Abstract. This paper is devoted to the experimental quantitative characterization of the shape and orientation distribution of ice particles in clouds. The characterization is based on measured and modeled elevation dependencies of the polarimetric parameters differential reflectivity and correlation coefficient. The polarimetric data are obtained using a newly developed 35 GHz cloud radar MIRA-35 with hybrid polarimetric configuration and scanning capabilities. The full procedure chain of the technical implementation and the realization of the setup of the hybrid-mode cloud radar for the shape determination are presented. This includes the description of phase adjustments in the transmitting paths, the introduction of the general data processing scheme, correction of the data for the differences of amplifications and electrical path lengths in the transmitting and receiving channels, the rotation of the polarization basis by 45 • , the correction of antenna effects on polarimetric measurements, the determination of spectral polarimetric variables, and the formulation of a scheme to increase the signal-to-noise ratio. Modeling of the polarimetric variables is based on existing backscattering models assuming the spheroidal representation of cloud scatterers. The parameters retrieved from the model are polarizability ratio and degree of orientation, which can be assigned to certain particle orientations and shapes. The developed algorithm is applied to a measurement of the hybridmode cloud radar taken on 20 October 2014 in Cabauw, the Netherlands, in the framework of the ACCEPT (Analysis of the Composition of Clouds with Extended Polarization Techniques) campaign. The case study shows the retrieved polarizability ratio and degree of orientation of ice particles for a cloud system of three cloud layers at different heights. Retrieved polarizability ratios are 0.43, 0.85, and 1.5 which correspond to oblate, quasi-spherical, and columnar ice particles, respectively. It is shown that the polarizability ratio is useful for the detection of aggregation/riming processes. The orientation of oblate and prolate particles is estimated to be close to horizontal while quasi-spherical particles were found to be more randomly oriented.

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supporting

confidence: 85%

Section: A Myagkov Et Al: Cloud Radar With Hybrid Mode Towards Estimentioning

confidence: 99%

Section: Mira-35 With Hybrid Modementioning

confidence: 99%

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Cloud radar with hybrid mode towards estimation of shape and orientation of ice crystals

et al. 2016

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“…Relationships between radar reflectivity and rainfall rate, median particle diameter, and liquid water content. we employed mathematical models characterized by frequently employed power-law nonlinearities (e.g., Lohmeier et al 1997;Uijlenhoet 2001) over a broad range of exponents, with particular interest in the amplification of error in R, W, and D 0 . The pervasiveness of power-law relationships is evident in the literature; these have even been developed to relate precipitation in the form of snowfall rate to radar reflectivity at W band (e.g., Matrosov et al 2008).…”

Section: Data Productsmentioning

confidence: 99%

Effects of Tunable Data Compression on Geophysical Products Retrieved from Surface Radar Observations with Applications to Spaceborne Meteorological Radars

Gabriel

Yeh

Tsay

2014

Journal of Atmospheric and Oceanic Technology

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This paper presents results and analyses of applying an international space data compression standard to weather radar measurements that can easily span eight orders of magnitude and typically require a large storage capacity as well as significant bandwidth for transmission. By varying the degree of the data compression, the nonlinear response of models that relates measured radar reflectivity and/or Doppler spectra to the moments and properties of the particle size distribution characterizing clouds and precipitation was analyzed. Preliminary results for the meteorologically important phenomena of clouds and light rain indicate that for a 60.5-dB calibration uncertainty, typical for the ground-based pulsed-Doppler 94-GHz (or 3.2 mm, W band) weather radar used as a proxy for spaceborne radar in this study, a lossless compression ratio of only 1.2 is achievable. However, further analyses of the nonlinear response of various models of rainfall rate, liquid water content, and median volume diameter show that a lossy data compression ratio exceeding 15 is realizable. The exploratory analyses presented are relevant to future satellite missions, where the transmission bandwidth is premium and storage requirements of vast volumes of data are potentially problematic.

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“…The rate of precipitation formation and the life cycle of mixed-phase clouds in general depend on the liquid and ice partitioning (e.g., Tremblay et al 1996;Jiang et al 2000;Khain et al 2011). Knowledge of the phase composition of clouds is important for development of remote sensing retrieval algorithms (e.g., Schols et al 1999) and validation of radar and lidar measurements (e.g., Lohmeier et al 1997;Iguchi et al 2012;Young 1974). The phase composition determines to a large extent the radiation balance (e.g., Oshchepkov and Isaka 1997) and is important for climate modeling (e.g., Sun and Shine 1995;Wilson 2000).…”

Section: Introductionmentioning

confidence: 99%

Analytical Investigation of Glaciation Time in Mixed-Phase Adiabatic Cloud Volumes

Pinsky

Хаин

Korolev

2014

Journal of the Atmospheric Sciences

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Glaciation in mixed-phase adiabatic cloudy parcels is investigated analytically using two new equations: the equation for coexistence of liquid water and ice and the mass balance equation. The analysis of glaciation time is performed for a vertically moving adiabatic mixed-phase cloud parcel. The effects of vertical velocity, liquid water content, and concentrations of ice particles, liquid droplets, temperature, and other parameters on the glaciation process are discussed. It is shown analytically that, for a certain envelope of vertical velocities, the glaciation time depends only on the vertical displacement of the parcel and does not depend on the trajectory along which the cloud parcel travels toward the glaciation point. Analytical dependencies of the glaciation time and of the altitude of glaciation on vertical velocity are presented. The results demonstrate a good agreement with those obtained using the corresponding parcel model. The limitations of the newly proposed approach are discussed as well, and it is shown that implementation of a simple correction factor allows one to calculate the glaciation time within a wide range of temperatures, from 08 down to 2308C.

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Classification of particles in stratiform clouds using the 33 and 95 GHz polarimetric cloud profiling radar system (CPRS)

Cited by 28 publications

References 35 publications

Cloud radar with hybrid mode towards estimation of shape and orientation of ice crystals

Cloud radar with hybrid mode towards estimation of shape and orientation of ice crystals

Effects of Tunable Data Compression on Geophysical Products Retrieved from Surface Radar Observations with Applications to Spaceborne Meteorological Radars

Analytical Investigation of Glaciation Time in Mixed-Phase Adiabatic Cloud Volumes

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