A Method for Determining Cirrus Cloud Particle Sizes Using Lidar and Radar Backscatter Technique

Intrieri, J. M.; Stephens, Graeme L.; Eberhard, Wynn L.; Uttal, Taneil

doi:10.1175/1520-0450(1993)032<1074:amfdcc>2.0.co;2

Cited by 103 publications

(78 citation statements)

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“…Millimetre microwave radars have been only applied to the study of hydrometeors and their sensitivity to ultragiant aerosol is mainly unknown. Studies focused on cirrus clouds report that the detection of ice particle with an effective radius lower than 30 mm using Ka-band radars should be not feasible, due to the their limited sensitivity to these particle sizes [Intrieri et al, 1993]. Nevertheless, this sensitivity threshold depends on the experimental design of the radar system.…”

Section: Introductionmentioning

confidence: 99%

Observation of non‐spherical ultragiant aerosol using a microwave radar

Madonna¹,

Amodeo²,

D’Amico³

et al. 2010

Geophysical Research Letters

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Observations of ultragiant aerosol particles performed at the CNR‐IMAA Atmospheric Observatory using a Ka‐Band Doppler radar in four different periods from 19 April to 13 May 2010 are presented. In the reported cases, the aerosol radar signatures are characterized by a similar scenario. In particular, the linear depolarization ratio shows values higher than −4 dB probably related to the effect of bulk density and to the non‐sphericity of the ultragiant particles. During the same period, volcanic aerosol layers coming from Eyjafjallajökull volcano were observed over most of European countries, including Southern Italy, using lidar technique. The observation of volcanic layers over Potenza by multi‐wavelength Raman lidar measurements suggests a volcanic origin of the ultragiant aerosol particles observed by the radar, revealing that these particles might travel in the atmosphere for more than 4000 km after their injection in the atmosphere.

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Section: Introductionmentioning

confidence: 99%

Observation of non‐spherical ultragiant aerosol using a microwave radar

Madonna¹,

Amodeo²,

D’Amico³

et al. 2010

Geophysical Research Letters

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“…The sign of the cirrus cloud feedback to climatic variation is sensitive to the effective ice particle radius and the ice water content (IWC) (Stephens et al, 1990). Using remote sensing, the effective ice particle radius can be determined by the radar/lidar backscatter ratio (Intrieri et al, 1993), and IWC can be estimated using the effective ice particle radius and radar reflectivity Z (Atlas et al, 1995; or by Z and cloud temperature T , but all these procedures depend upon the accurate determination of radar reflectivity Z, which is not only sensitive to the particle density distributions , but is also expected to be affected by different ice particle shapes in cirrus clouds (Evans and Stephens, 1995).…”

Section: Introductionmentioning

confidence: 99%

Error analysis of backscatter from discrete dipole approximation for different ice particle shapes

Illingworth

1997

Atmospheric Research

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Ice sphere backscatter has been calculated using both Mie theory and the discrete dipole approximation (DDA) at a wavelength of 3.2 mm (94 GHz). The electric dipole, magnetic dipole and electric quadrupole contributions to spherical particle backscatter have been analyzed. The results show that there is a resonance area around particle size parameter of 1.5, where the calculated backscatter errors are very large due to the neglect of the magnetic dipole, and this is confirmed by applying Mie theory to 8.66 mm (35 GHz) and 3.21 cm (X-band) wavelengths. Based on the backscatter calculation using a cube and a hexagon column randomly oriented in space, it was found that the backscatter error from the inaccurate representation of the particle surface shape is much smaller than that from the neglect of the magnetic dipole, and the resonance occurs at different particle sizes depending upon the exact particle shapes. At a wavelength of 3.2 mm, the particle shape has little effect on backscatter when volume-equivalent spherical particle radius r v < 500 /zm, and Rayleigh backscatter can be used as a reasonable approximation for r v < 300 /xm. © 1997 Elsevier Science B.V.

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“…Eberhard (1993) showed that the backscatter-to-extinction ratio S is a good indicator of the mean or effective radius of a cloud drop size distribution. When the lidar probes an optically thick cloud, the average value of S over the penetration depth can be obtained by integrating the measured, calibrated backscatter.…”

Section: ) Path-averaged Mean Radius or Effective Radius Of Dropsmentioning

confidence: 99%

“…CO, lidar backscatter scales as ND2. A method was developed earlier (Intrieri et al, 1993) to retrieve vertical profiles of the,effective radius of the cirrus particle size distribution from the ratio of calibrated radar and lidar backscatter.…”

Section: ) Cirrus Particle Size Microphysics From Radar and Co Lidarmentioning

confidence: 99%

Additional development of remote sensing techniques for observing morphology, microphysics, and radiative properties of clouds and tests using a new, robust CO{sub 2} lidar. Final report

Eberhard¹,

Brewer²,

Intrieri³

1998

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SUMMARYA three-year project with a goal of advancing CO, lidar technology and measurement An eyesafe, infrared lidar with good sensitivity and improved Doppler accuracy was techniques for cloud studies was successfully completed.designed, constructed, and demonstrated. Dual-wavelength operation was achieved. A major leap forward in robustness was demonstrated.Great Plains CART site. The first used an older lidar and was intended primarily for measurement technique development. The second used the new lidar and was primarily a demonstration and evaluation of its performance. measurement techniques using CO, lidar. The radadlidar concept for deriving cirrus particle size information was expanded to include retrieval of profiles of ice water content and number concentration. An analysis of the difference in vertical Doppler measured by the two instruments showed useful information on the breadth of the size distribution, but separation of air from particle settling motions would be quite difficult. Path-averaged effective radius of cloud droplets were derived from CO, lidar measurements. A comparison with aircraft in situ measurements was encouraging, but experimenta I limitations prevented any clear conclusions about the accuracy of this new method. A paper presenting the theoretical basis for dual-wavelength CO, lidar discrimination of ice and water clouds was finalized and published. The LIRAD method for obtaining cirrus optical parameters was adapted to CO, lidar and demonstrated.obtained with a visible-wavelength lidar and cloud radar. CO, lidars were operated as part of two Intensive Operations Periods at the SouthernProgress was demonstrated in the development, evaluation, and application of A simulation showed that the profile of water cloud microphysical parameters could be DISCLAIMER

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A Method for Determining Cirrus Cloud Particle Sizes Using Lidar and Radar Backscatter Technique

Cited by 103 publications

References 0 publications

Observation of non‐spherical ultragiant aerosol using a microwave radar

Observation of non‐spherical ultragiant aerosol using a microwave radar

Error analysis of backscatter from discrete dipole approximation for different ice particle shapes

Additional development of remote sensing techniques for observing morphology, microphysics, and radiative properties of clouds and tests using a new, robust CO{sub 2} lidar. Final report

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