Observations of Mixed-Phase Precipitation within a CaPE Thunderstorm

Smith, Paul L.; Musil, Dennis J.; Detwiler, Andrew; Ramachandran, Rahul

doi:10.1175/1520-0450(1999)038<0145:oomppw>2.0.co;2

Cited by 32 publications

(36 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hubbert et al (1998) showed that 30%-40% of the hailstones from the storm they studied had frozen drops as embryos, strongly suggesting the importance of Z DR columns in hail growth. Smith et al (1999) agreed that freezing of drops is important for the LDR enhancements and as a possible hail embryo source and presented photographic evidence of partially frozen raindrops in an LDR cap, confirming inferences from the polarimetric radar measurements. Kennedy et al (2001) showed that these LDR caps on Z DR columns preceded the occurrence of hail at the surface.…”

Section: A Observations Of Z Dr Columnssupporting

confidence: 59%

“…Reductions in r hy and enhancements in LDR (''LDR caps'') atop Z DR columns were also reported in Bringi et al (1996Bringi et al ( , 1997, Jameson et al (1996), Hubbert et al (1998), Smith et al (1999, and Kennedy et al (2001). Jameson et al (1996) explained the LDR enhancements by wet frozen drops growing in environments of high cloud water content, whereas Bringi et al (1997) argued wet growth was not likely in the storms that they investigated.…”

Section: A Observations Of Z Dr Columnsmentioning

confidence: 76%

See 1 more Smart Citation

The Anatomy and Physics of ZDR Columns: Investigating a Polarimetric Radar Signature with a Spectral Bin Microphysical Model

Kumjian

Хаин

Benmoshe

et al. 2014

Journal of Applied Meteorology and Climatology

152

127

View full text Add to dashboard Cite

Polarimetric radar observations of deep convective storms frequently reveal columnar enhancements of differential reflectivity Z DR . Such ''Z DR columns'' can extend upward more than 3 km above the environmental 08C level, indicative of supercooled liquid drops being lofted by the updraft. Previous observational and modeling studies of Z DR columns are reviewed. To address remaining questions, the Hebrew University Cloud Model, an advanced spectral bin microphysical model, is coupled with a polarimetric radar operator to simulate the formation and life cycle of Z DR columns in a deep convective continental storm. In doing so, the mechanisms by which Z DR columns are produced are clarified, including the formation of large raindrops in the updraft by recirculation of smaller raindrops formed aloft back into the updraft at low levels. The internal hydrometeor structure of Z DR columns is quantified, revealing the transition from supercooled liquid drops to freezing drops to hail with height in the Z DR column. The life cycle of Z DR columns from early formation, through growth to maturity, to demise is described, showing how hail falling out through the weakening or ascending updraft bubble dominates the reflectivity factor Z H , causing the death of the Z DR column and leaving behind its ''ghost'' of supercooled drops. In addition, the practical applications of Z DR columns and their evolution are explored. The height of the Z DR column is correlated with updraft strength, and the evolution of Z DR column height is correlated with increases in Z H and hail mass content at the ground after a lag of 10-15 min.

show abstract

Section: A Observations Of Z Dr Columnssupporting

confidence: 59%

Section: A Observations Of Z Dr Columnsmentioning

confidence: 76%

The Anatomy and Physics of ZDR Columns: Investigating a Polarimetric Radar Signature with a Spectral Bin Microphysical Model

Kumjian

Хаин

Benmoshe

et al. 2014

Journal of Applied Meteorology and Climatology

152

127

View full text Add to dashboard Cite

show abstract

“…Smith et al (1999) reported, for a model of the freezing of drops in updraft regions, that the required freezing time and the final diameter in the updraft region are functions of initial raindrop size. In this study, the values of Z DR around the ambient 08C level are approximately 1 dB in the CNL area in Fig.…”

Section: B Vertical Change In Height Of the Mlsm Level In The CML Rementioning

confidence: 99%

Polarimetric Radar Observation of the Melting Layer in a Convective Rainfall System during the Rainy Season over the East China Sea

Shusse

Takahashi

Nakagawa

et al. 2011

Journal of Applied Meteorology and Climatology

View full text Add to dashboard Cite

During the rainy season over the East China Sea, convective rainfalls often show melting layer (ML) characteristics in polarimetric radar variables. In this research, the appearance ratio of the ML (the ratio of rainfall area accompanied by polarimetric ML signatures) and the variation in height of the level of the ML signature maximum (MLSM level; defined by the level of the r hv minimum in the ML) in a convective rainfall region in a rainfall system over the East China Sea observed on 2 June 2006 were studied using C-band polarimetric radar (COBRA). For this analysis, a method of rainfall type classification that evaluates the presence of an ML in addition to providing conventional convective-stratiform classification using rangeheight indicator (RHI) observation data was developed. This rainfall type classification includes two steps: conventional convective-stratiform separation using the horizontal distribution of Z h at 2-km altitude, and ML detection using the vertical profile of r hv at each horizontal grid point. Using a combination of these two classifications, the following four rainfall types were identified: 1) convective rainfall with an ML, 2) convective rainfall with no ML, 3) stratiform rainfall with an ML, and 4) stratiform rainfall with no ML. An ML was detected in 53.9% of the convective region in the rainfall system. Using the same definition, an ML was detected in 83.1% of the stratiform region. The ML in the convective region showed a marked decrease in r hv coincident with an increase in Z DR around the ambient 08C level, as did that in the stratiform region. Melting aggregated snow was the likely cause of the ML signature in the convective region. The average height of the MLSM level in the convective region was 4.64 km, which is 0.46 km higher than that in the stratiform region (4.18 km) and 0.27 km higher than the ambient 08C level (4.37 km).

show abstract

“…Above the freezing level, we assume that there is a mixedphase layer. Analyses of differential reflectivity (Z DR ) and linear depolarization ratio (LDR) observations made by polarimetric radars in several other studies (Smith et al 1999;Bringi et al 1997;Balakrishnan and Zrnic 1990;and Sax and Keller 1980) lead us to infer a layer of mixed-phase particles, consisting of water and ice, to a substantial height above the freezing level, because of vigorous vertical motions in convective updrafts. The relatively strong reflectivity (>30 dBZ) observed by PR in convective towers above the freezing level (see Fig.…”

Section: Model and Results For Convective Rainmentioning

confidence: 99%

TRMM Precipitation Radar and Microwave Imager Observations of Convective and Stratiform Rain over Land and their Theoretical Implications.

Prabhakara

Iacovazzi

Yoo

2002

Journal of the Meteorological Society of Japan

View full text Add to dashboard Cite

Observations of brightness temperature, Tb, made over land regions by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) radiometer are analyzed with the help of nearly simultaneous measurements of the vertical profiles of reflectivity factor, Z, made by the Precipitation Radar (PR) onboard the TRMM satellite. Furthermore, this analysis is done separately over convective and stratiform rain regions. This examination reveals a clear relationship between TMI and PR data. Possible explanation for this relationship is explored with the help of radiative transfer calculations. With this approach, we demonstrate that the 85 GHz observations of TMI can be simulated crudely from the observations of Z. However, the 37 and 19 GHz observations are not as well simulated, possibly because of horizontal non-uniformity in the hydrometeor distribution in the broad footprints of these channels and contamination introduced by land-surface emissivity. On the other hand, from TMI and PR observations, we find that the brightness temperature difference (T19-T37) minimizes these sources of error. Our simulations of (T19-T37) over convective rain regions are in reasonable agreement with this finding. This investigation indicates that the TMI 85 GHz channel yields the best information about rain over tropical land, because it has minimal surface contamination, strong extinction, and a fine footprint. The brightness temperature difference (T19-T37) can supplement the information given by the 85 GHz channel.

show abstract

Observations of Mixed-Phase Precipitation within a CaPE Thunderstorm

Cited by 32 publications

References 21 publications

The Anatomy and Physics of ZDR Columns: Investigating a Polarimetric Radar Signature with a Spectral Bin Microphysical Model

The Anatomy and Physics of ZDR Columns: Investigating a Polarimetric Radar Signature with a Spectral Bin Microphysical Model

Polarimetric Radar Observation of the Melting Layer in a Convective Rainfall System during the Rainy Season over the East China Sea

TRMM Precipitation Radar and Microwave Imager Observations of Convective and Stratiform Rain over Land and their Theoretical Implications.

Contact Info

Product

Resources

About