Millimeter wave scattering from ice crystals and their aggregates: Comparing cloud model simulations with X- and Ka-band radar measurements

Giovanni Botta, Kultegin Aydin, Johannes Verlinde, Alexander E. Avramov, Andrew S. Ackerman, Ann M. Fridlind, Greg M. McFarquhar, Mengistu Wolde

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Arctic clouds are often mixed-phase, such that the radiative properties of the clouds are a strong function of the relative amounts of cloud liquid and ice. Modeling studies have shown that the poorly understood ice phase processes are the regulators of the liquid water fraction. However, evaluating the fidelity of the model ice parameterizations has proven to be a difficult task. This study evaluates results of different ice microphysics representations in a cloud resolving model (CRM) using cloud radar measurements. An algorithm is presented to generate realistic ice crystals and their aggregates from which radar backscattering cross sections may be calculated using a generalized solution for a cluster of spheres. The aggregate is composed of a collection of ice crystals, each of which is constructed from a cluster of tiny ice spheres. Each aggregate satisfies the constraints set by the component crystal type and the mass-dimensional relationship used in the cloud resolving model, but is free to adjust its aspect ratio. This model for calculating radar backscattering is compared to two spherical and two spheroidal (bulk model) representations for ice hydrometeors. It was found that a refined model for representing the ice hydrometeors, both pristine crystals and their aggregates, is required in order to obtain good comparisons between the CRM calculations and the radar measurements. The addition of the radar-CRM comparisons to CRM-in situ measurements comparisons allowed conclusions about the appropriateness of different CRM ice microphysics parameterizations.

Original languageEnglish (US)
Article numberD00T04
JournalJournal of Geophysical Research Atmospheres
Volume116
Issue number17
DOIs
StatePublished - Jan 1 2011

Fingerprint

Radar measurement
wave scattering
radar measurement
radar
ice crystal
Ice
Millimeter waves
millimeter waves
crystals
simulation models
ice
Scattering
Crystals
simulation
hydrometeors
Radar
Backscattering
Parameterization
parameterization
backscattering

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Botta, Giovanni ; Aydin, Kultegin ; Verlinde, Johannes ; Avramov, Alexander E. ; Ackerman, Andrew S. ; Fridlind, Ann M. ; McFarquhar, Greg M. ; Wolde, Mengistu. / Millimeter wave scattering from ice crystals and their aggregates : Comparing cloud model simulations with X- and Ka-band radar measurements. In: Journal of Geophysical Research Atmospheres. 2011 ; Vol. 116, No. 17.
@article{dc8dddde9fd649f89bb3244c5d154bf7,
title = "Millimeter wave scattering from ice crystals and their aggregates: Comparing cloud model simulations with X- and Ka-band radar measurements",
abstract = "Arctic clouds are often mixed-phase, such that the radiative properties of the clouds are a strong function of the relative amounts of cloud liquid and ice. Modeling studies have shown that the poorly understood ice phase processes are the regulators of the liquid water fraction. However, evaluating the fidelity of the model ice parameterizations has proven to be a difficult task. This study evaluates results of different ice microphysics representations in a cloud resolving model (CRM) using cloud radar measurements. An algorithm is presented to generate realistic ice crystals and their aggregates from which radar backscattering cross sections may be calculated using a generalized solution for a cluster of spheres. The aggregate is composed of a collection of ice crystals, each of which is constructed from a cluster of tiny ice spheres. Each aggregate satisfies the constraints set by the component crystal type and the mass-dimensional relationship used in the cloud resolving model, but is free to adjust its aspect ratio. This model for calculating radar backscattering is compared to two spherical and two spheroidal (bulk model) representations for ice hydrometeors. It was found that a refined model for representing the ice hydrometeors, both pristine crystals and their aggregates, is required in order to obtain good comparisons between the CRM calculations and the radar measurements. The addition of the radar-CRM comparisons to CRM-in situ measurements comparisons allowed conclusions about the appropriateness of different CRM ice microphysics parameterizations.",
author = "Giovanni Botta and Kultegin Aydin and Johannes Verlinde and Avramov, {Alexander E.} and Ackerman, {Andrew S.} and Fridlind, {Ann M.} and McFarquhar, {Greg M.} and Mengistu Wolde",
year = "2011",
month = "1",
day = "1",
doi = "10.1029/2011JD015909",
language = "English (US)",
volume = "116",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "2169-897X",
number = "17",

}

Millimeter wave scattering from ice crystals and their aggregates : Comparing cloud model simulations with X- and Ka-band radar measurements. / Botta, Giovanni; Aydin, Kultegin; Verlinde, Johannes; Avramov, Alexander E.; Ackerman, Andrew S.; Fridlind, Ann M.; McFarquhar, Greg M.; Wolde, Mengistu.

In: Journal of Geophysical Research Atmospheres, Vol. 116, No. 17, D00T04, 01.01.2011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Millimeter wave scattering from ice crystals and their aggregates

T2 - Comparing cloud model simulations with X- and Ka-band radar measurements

AU - Botta, Giovanni

AU - Aydin, Kultegin

AU - Verlinde, Johannes

AU - Avramov, Alexander E.

AU - Ackerman, Andrew S.

AU - Fridlind, Ann M.

AU - McFarquhar, Greg M.

AU - Wolde, Mengistu

PY - 2011/1/1

Y1 - 2011/1/1

N2 - Arctic clouds are often mixed-phase, such that the radiative properties of the clouds are a strong function of the relative amounts of cloud liquid and ice. Modeling studies have shown that the poorly understood ice phase processes are the regulators of the liquid water fraction. However, evaluating the fidelity of the model ice parameterizations has proven to be a difficult task. This study evaluates results of different ice microphysics representations in a cloud resolving model (CRM) using cloud radar measurements. An algorithm is presented to generate realistic ice crystals and their aggregates from which radar backscattering cross sections may be calculated using a generalized solution for a cluster of spheres. The aggregate is composed of a collection of ice crystals, each of which is constructed from a cluster of tiny ice spheres. Each aggregate satisfies the constraints set by the component crystal type and the mass-dimensional relationship used in the cloud resolving model, but is free to adjust its aspect ratio. This model for calculating radar backscattering is compared to two spherical and two spheroidal (bulk model) representations for ice hydrometeors. It was found that a refined model for representing the ice hydrometeors, both pristine crystals and their aggregates, is required in order to obtain good comparisons between the CRM calculations and the radar measurements. The addition of the radar-CRM comparisons to CRM-in situ measurements comparisons allowed conclusions about the appropriateness of different CRM ice microphysics parameterizations.

AB - Arctic clouds are often mixed-phase, such that the radiative properties of the clouds are a strong function of the relative amounts of cloud liquid and ice. Modeling studies have shown that the poorly understood ice phase processes are the regulators of the liquid water fraction. However, evaluating the fidelity of the model ice parameterizations has proven to be a difficult task. This study evaluates results of different ice microphysics representations in a cloud resolving model (CRM) using cloud radar measurements. An algorithm is presented to generate realistic ice crystals and their aggregates from which radar backscattering cross sections may be calculated using a generalized solution for a cluster of spheres. The aggregate is composed of a collection of ice crystals, each of which is constructed from a cluster of tiny ice spheres. Each aggregate satisfies the constraints set by the component crystal type and the mass-dimensional relationship used in the cloud resolving model, but is free to adjust its aspect ratio. This model for calculating radar backscattering is compared to two spherical and two spheroidal (bulk model) representations for ice hydrometeors. It was found that a refined model for representing the ice hydrometeors, both pristine crystals and their aggregates, is required in order to obtain good comparisons between the CRM calculations and the radar measurements. The addition of the radar-CRM comparisons to CRM-in situ measurements comparisons allowed conclusions about the appropriateness of different CRM ice microphysics parameterizations.

UR - http://www.scopus.com/inward/record.url?scp=80053082019&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80053082019&partnerID=8YFLogxK

U2 - 10.1029/2011JD015909

DO - 10.1029/2011JD015909

M3 - Article

AN - SCOPUS:80053082019

VL - 116

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 2169-897X

IS - 17

M1 - D00T04

ER -