Microphysical Ice Cloud Data

Field Campaign Data

A summary of the in situ data is presented in Table 1. Field campaigns located in the midlatitudes include the First ISCCP Regional Experiments (FIRE; ISCCP refers to the International Satellite Cloud Climatology Project) in Madison, WI in 1986 and Coffeyville, KS in 1991. Another midlatitude data set was derived in the vicinity of the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Lamont, Oklahoma in March, 2000. The midlatitude cirrus generally had temperatures ranging from -65^oC to -20^oC, with visible optical thickness values between 0.5 and 7. These ice cloud layers formed in association with synoptic-scale lifting.

In 1998 and 1999, four field campaigns were conducted under the auspices of the Tropical Rainfall Measurement Mission (TRMM). While the purpose of the campaigns was to evaluate the performance of the TRMM radar and radiometer retrieval algorithms, they also provided validation data for TRMM mesoscale and regional-scale models, as well as in situ data from deep tropical cirrus and stratiform precipitating clouds. The tropical data used in this study were obtained from the flights conducted in Kwajalein, Marshall Islands [Kwajalein Experiment: KWAJEX] in 1999. The tropical ice cloud temperatures ranged from -70^oC to 0^oC, with optical thickness values between 20 and 30, and formed in association with deep convection. Additionally, recent high-quality measurements have been acquired during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) during a series of flights by the NASA WB57F aircraft and the University of North Dakota (UND) Citation. The CRYSTAL-FACE data used in this study were obtained from a flight track recorded off the coast of Nicaragua, and provides data from extremely cold cirrus (-76 ^oC to -58^oC).

Imaging probes provide the aircraft-based size spectra measurements (Heymsfield et al. 2002). The Particle Measuring Systems, Inc. (PMS) 2D-C probes provide sizes from about 50 to 1000 microns. The 2D-C resolution is 25 microns for FIRE I but 33 microns for the other campaigns listed in Table 1. A PMS 2D-P probe measured larger particle sizes (1000 to more than 3000 microns) for the FIRE-I and ARM campaigns, with resolutions of 100 microns for FIRE-I and 200 microns for ARM. Additionally for the TRMM field campaign, large particle sizes from 1 to more than 30 mm were obtained from a Stratton Park Engineering Com-pany (SPEC) high volume precipitation spectrometer (HVPS) probe with a resolution of 0.2 mm. A SPEC cloud particle imager (CPI) provided imagery for the ARM and TRMM campaigns over a range of sizes from 20 to 2000 microns with a 2-micron resolution. While the CPI probe provides spectacular imagery of the ice particles, its accuracy in measuring PSDs has yet to be established. Therefore the CPI data were not used to evaluate the numbers of small crystals in the PSDs.

Particle size distributions and habit imagery from FIRE II were obtained from balloon-borne replicators. Particle sizes were obtained over a range from 10 to between 500 and 1000 microns, with a resolution of about 2 microns. The replicators measure size distributions and yield particle imagery reliably even for the smallest particles in the 10-20 micron diameter range. The continuous replicator observations are averaged over vertical distances of about 300 m (Heymsfield and Miloshevich 2003). Aircraft data from FIRE-II are also available, but the forward scattering spectrometer probe (FSSP) data, which provides particle sizes from 2 to 30 microns), are thought to be unreliable due to possible particle breakup in the probe inlet and are not used in this study. Further discussion of the measurement techniques and analysis of field campaign data are provided in Heymsfield and Miloshevich (2003), Heymsfield et al. (2002, 2004), and Heymsfield (2004), with full references provided below.

References

Heymsfield, A. J., A. Bansemer, P. R. Field, S. L. Durden, J. Stith, J. E. Dye, W. Hall, and T. Grainger, 2002: Observations and parameterizations of particle size distribu-tions in deep tropical cirrus and stratiform precipitating clouds: Results from in situ observations in TRMM field campaigns. J. Atmos. Sci., 59, 3457-3491.

Heymsfield, A. J., and L. M. Miloshevich, 2003: Parameterizations for the cross-sectional area and extinction of cirrus and stratiform ice cloud particles. J. Atmos. Sci., 60, 936-956.

Heymsfield, A. J., 2003: Properties of Tropical and Midlatitude Ice Cloud Particle Ensembles: Part I: Median Mass Diameters and Terminal Velocities. J. Atmos. Sci., 60, 2592--2611.

Heymsfield, A. J., C. G. Schmitt, A. Bansemer, D. Baumgardner, E. M. Weinstock, J. T. Smith, and D. Sayres, 2004: Effective ice particle densities for cold anvil cirrus. Geophys. Res. Ltrs., 31, L02101.

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	Field Campaign Data A summary of the in situ data is presented in Table 1. Field campaigns located in the midlatitudes include the First ISCCP Regional Experiments (FIRE; ISCCP refers to the International Satellite Cloud Climatology Project) in Madison, WI in 1986 and Coffeyville, KS in 1991. Another midlatitude data set was derived in the vicinity of the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Lamont, Oklahoma in March, 2000. The midlatitude cirrus generally had temperatures ranging from -65^oC to -20^oC, with visible optical thickness values between 0.5 and 7. These ice cloud layers formed in association with synoptic-scale lifting. In 1998 and 1999, four field campaigns were conducted under the auspices of the Tropical Rainfall Measurement Mission (TRMM). While the purpose of the campaigns was to evaluate the performance of the TRMM radar and radiometer retrieval algorithms, they also provided validation data for TRMM mesoscale and regional-scale models, as well as in situ data from deep tropical cirrus and stratiform precipitating clouds. The tropical data used in this study were obtained from the flights conducted in Kwajalein, Marshall Islands [Kwajalein Experiment: KWAJEX] in 1999. The tropical ice cloud temperatures ranged from -70^oC to 0^oC, with optical thickness values between 20 and 30, and formed in association with deep convection. Additionally, recent high-quality measurements have been acquired during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) during a series of flights by the NASA WB57F aircraft and the University of North Dakota (UND) Citation. The CRYSTAL-FACE data used in this study were obtained from a flight track recorded off the coast of Nicaragua, and provides data from extremely cold cirrus (-76 ^oC to -58^oC). Imaging probes provide the aircraft-based size spectra measurements (Heymsfield et al. 2002). The Particle Measuring Systems, Inc. (PMS) 2D-C probes provide sizes from about 50 to 1000 microns. The 2D-C resolution is 25 microns for FIRE I but 33 microns for the other campaigns listed in Table 1. A PMS 2D-P probe measured larger particle sizes (1000 to more than 3000 microns) for the FIRE-I and ARM campaigns, with resolutions of 100 microns for FIRE-I and 200 microns for ARM. Additionally for the TRMM field campaign, large particle sizes from 1 to more than 30 mm were obtained from a Stratton Park Engineering Com-pany (SPEC) high volume precipitation spectrometer (HVPS) probe with a resolution of 0.2 mm. A SPEC cloud particle imager (CPI) provided imagery for the ARM and TRMM campaigns over a range of sizes from 20 to 2000 microns with a 2-micron resolution. While the CPI probe provides spectacular imagery of the ice particles, its accuracy in measuring PSDs has yet to be established. Therefore the CPI data were not used to evaluate the numbers of small crystals in the PSDs. Particle size distributions and habit imagery from FIRE II were obtained from balloon-borne replicators. Particle sizes were obtained over a range from 10 to between 500 and 1000 microns, with a resolution of about 2 microns. The replicators measure size distributions and yield particle imagery reliably even for the smallest particles in the 10-20 micron diameter range. The continuous replicator observations are averaged over vertical distances of about 300 m (Heymsfield and Miloshevich 2003). Aircraft data from FIRE-II are also available, but the forward scattering spectrometer probe (FSSP) data, which provides particle sizes from 2 to 30 microns), are thought to be unreliable due to possible particle breakup in the probe inlet and are not used in this study. Further discussion of the measurement techniques and analysis of field campaign data are provided in Heymsfield and Miloshevich (2003), Heymsfield et al. (2002, 2004), and Heymsfield (2004), with full references provided below. References Heymsfield, A. J., A. Bansemer, P. R. Field, S. L. Durden, J. Stith, J. E. Dye, W. Hall, and T. Grainger, 2002: Observations and parameterizations of particle size distribu-tions in deep tropical cirrus and stratiform precipitating clouds: Results from in situ observations in TRMM field campaigns. J. Atmos. Sci., 59, 3457-3491. Heymsfield, A. J., and L. M. Miloshevich, 2003: Parameterizations for the cross-sectional area and extinction of cirrus and stratiform ice cloud particles. J. Atmos. Sci., 60, 936-956. Heymsfield, A. J., 2003: Properties of Tropical and Midlatitude Ice Cloud Particle Ensembles: Part I: Median Mass Diameters and Terminal Velocities. J. Atmos. Sci., 60, 2592--2611. Heymsfield, A. J., C. G. Schmitt, A. Bansemer, D. Baumgardner, E. M. Weinstock, J. T. Smith, and D. Sayres, 2004: Effective ice particle densities for cold anvil cirrus. Geophys. Res. Ltrs., 31, L02101. Back to Bryan A. Baum's Home Page