Synoptic-Physical Implications of 1.25-CM Vertical-Beam Radar Echoes

Boucher, Roland J.

doi:10.1175/1520-0469(1959)016<0312:spiocv>2.0.co;2

Cited by 20 publications

(5 citation statements)

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“…Generating cells are a critical component of the comma head precipitation structure. Their existence has been confirmed in a variety of environments (e.g., Marshall 1953;Gunn et al 1954;Boucher 1959;Wexler 1955;Douglas et al 1957;Wexler and Atlas 1959;Henrion et al 1978;Houze et al 1981;Browning 1983;Locatelli et al 1983;Businger and Hobbs 1987;Sienkiewicz et al 1989;Syrett et al 1995;Wolde and Vali 2002;Evans et al 2005;McFarquhar et al 2011;Cunningham and Yuter 2014;Kumjian et al 2014;Rauber et al 2014b;Rosenow et al 2014). Statistical analyses of the radar reflectivity and radial velocity structure of GCs presented by Rosenow et al (2014) show that the cells are typically about 1-2 km in horizontal and vertical extent and have convective vertical velocities of 61-2 m s 21 or more.…”

Section: Introductionsupporting

confidence: 81%

Microphysical Properties of Convectively Generated Fall Streaks within the Stratiform Comma Head Region of Continental Winter Cyclones

Plummer

McFarquhar

Rauber

et al. 2015

Journal of the Atmospheric Sciences

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This paper presents analyses of the microphysical structure of comma head stratiform precipitation in 14 continental cyclones, focusing on fall streaks of hydrometeors produced by cloud-top convective generating cells. Data were obtained at temperatures between 248 and 2458C using in situ instrumentation and the W-band University of Wyoming Cloud Radar, all operated aboard the National Science Foundation/National Center for Atmospheric Research C-130. Analyses are presented first for a case study of one cyclone, followed by statistical analyses of the full dataset.Using radar-based objective classifications, the statistical percentile number concentrations averaged 1.9 times larger within the fall streaks compared to the regions between them, and the corresponding ice water content and median mass diameter values averaged 2.2 and 1.1 times larger. Ice-phase conditions were predominant within the stratiform precipitation, with deposition and aggregation the primary ice growth mechanisms. No distinct vertical velocity signatures were associated with the fall streaks, and similar ice growth mechanisms were common within and between them.Combined with observations of cloud-top generating cells in many of the same cyclones, these analyses provide a more complete description of the comma head microphysical structure and the physical processes producing precipitation. Whereas the generating cells are critical to nucleation and initial ice growth, the majority of ice growth (exceeding 90% of the median ice water contents in the case study) typically occurred below the generating-cell level, where enhanced moisture associated with synoptic-scale ascent was present.

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Section: Introductionsupporting

confidence: 81%

Microphysical Properties of Convectively Generated Fall Streaks within the Stratiform Comma Head Region of Continental Winter Cyclones

Plummer

McFarquhar

Rauber

et al. 2015

Journal of the Atmospheric Sciences

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“…1 Early studies using vertically pointing radars, such as those of Marshall (1953), Gunn et al (1954), Boucher (1959), Wexler (1955), Langleben (1956), Douglas et al (1957), and Wexler and Atlas (1959), noted kilometer-scale GC activity near cloud top that produced precipitation streamers, or fall streaks, into stratiform cloud layers below. Subsequent research involving Doppler radar (Carbone and Bohne 1975) estimated maximum vertical velocities on the order of 61.5 m s 21 for the GC convection.…”

Section: Introductionmentioning

confidence: 99%

Structure and Statistical Analysis of the Microphysical Properties of Generating Cells in the Comma Head Region of Continental Winter Cyclones

Plummer

McFarquhar

Rauber

et al. 2014

Journal of the Atmospheric Sciences

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This paper presents analyses of the microphysical structure of cloud-top convective generating cells at temperatures between 2108 and 2558C across the comma head of 11 continental cyclones, using data collected by the W-band Wyoming Cloud Radar and in situ instrumentation aboard the National Science Foundation (NSF)/NCAR C-130. A case study of one cyclone is presented, followed by statistical analyses of the entire dataset.Ice particle number concentrations averaged 1.9 times larger inside generating cells compared to outside, and derived ice water contents and median mass diameters averaged 2.2 and 1.1 times larger in cells, respectively. Supercooled water was directly measured at temperatures between 231.48 and 211.18C, with the median and 95th-percentile liquid water content increasing from ;0.09 to 0.12 g m 23 and 0.14 to 0.28 g m 23 over this temperature range, respectively. Liquid water was present in 26% of observations within cells and 18% of observations between cells over the same temperature range, and it was nearly ubiquitous at temperatures above 2168C.The larger ice particle concentrations in cells are consistent with greater ice production in convective updrafts. The increased mass and diameter of the ice particles demonstrate that generating cells provide environments favorable for enhanced particle growth. The impact of water saturation and supercooled water in the cells was evident, with rapid particle growth by diffusion and sometimes riming apparent, in addition to aggregation. Turbulent mixing lessened the observed differences between cells and surrounding regions, with supercooled water observed within and between cells, similar habits within and between cells, and rimed particles evident even in ice-phase conditions.

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“…In the larger scale employment of radar, efforts have been made to combine visual and radar return from clouds with the existing synoptic pattern [Boucher, 1959;Wilk, 1958] and to demonstrate the successful forecasting technique of combining the returns from several radars to give echo patterns on a synoptic scale [Ligda, 1958b]. By associating precipitation echoes with liquid water content, it has been shown that radar can be used effectively to study the distribution of three dimensional winds in the atmosphere [Kessler, 1958].…”

Section: Radar Meteorologymentioning

confidence: 99%

URSI National Committee Report: Commission 2. Tropospheric Radio Propagation

1960

J. RES. NATL. BUR. STAN. SECT. D. RAD. PROP.

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The USA National Committee of Commission 2 Tropospheric Radio Propagation , has been quite active sin ce the XIIth General Assembly held in Boulder, Colo ., 1957. This report contains a brief summary of the work of this Commission arranged in accordance with the topics to be discussed at the XlIIth General Assembly, London, 1960. The bibliography at the end of this report includes principally the papers published since the XIIth General Assembly. References to work that is not generally available in the published literature have not been included.The following m embers of Commission 2 participated in the preparation of this report: I. H. Gerks, US Chairman, J . ",V. H erbstreit, coordinator, W.

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Synoptic-Physical Implications of 1.25-CM Vertical-Beam Radar Echoes

Cited by 20 publications

References 0 publications

Microphysical Properties of Convectively Generated Fall Streaks within the Stratiform Comma Head Region of Continental Winter Cyclones

Microphysical Properties of Convectively Generated Fall Streaks within the Stratiform Comma Head Region of Continental Winter Cyclones

Structure and Statistical Analysis of the Microphysical Properties of Generating Cells in the Comma Head Region of Continental Winter Cyclones

URSI National Committee Report: Commission 2. Tropospheric Radio Propagation

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