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Dynamical and Microphysical Characteristics of Arctic Clouds Obtained From Observations Collected During FIRE.ACE Flights Over SHEBA in April 1998 |
(1;2)Meteorological Service of Canada, Cloud Physics Research Division, 4905
Dufferin St., Toronto, ONT. M3H-5T4, Canada,
(3)National Environmental Satellite, Data, and Information Service, National
Oceanic and Atmospheric Administration, 1225 West Dayton St., Madison, WI
53706,
(4)Air Quality Processes Research Division, Meteorological Service
of Canada, Center For Atmospheric Research Experiments, R-R#1, Egbert, Ontario,
L0L 1N0, Canada,
(5;6)NOAA R/E/ET6, 325 Broadway, Boulder, CO 80303
ismail.gultepe@ec.gc.ca
The purpose of this study is to better understand the dynamical and microphysical processes within Arctic clouds which occurred over the SHEBA ship during FIRE.ACE in April of 1998. The observations used in the present study were collected on four days by the instruments mounted onboard the National Research Council (NRC) Convair, as well as, NOAA AVHRR satellite, SHEBA surface based NOAA Doppler radar (35 GHz, Ka- Band), and NOAA polarized lidar (0.523 micrometer) measurements. The aircraft observations were collected at 32Hz (3-m scale). The MSC lidar (1.064 micrometer) operated onboard the Convair, the NOAA Doppler radar, and NOAA lidar observations represent 100 m, 45 m, and 30 m in the horizontal, respectively. The AVHRR observations representing 5-km horizontal resolution were used to estimate particle size, phase, and optical thickness. Constant altitude flight legs were made at close to the ocean surface. Vertical air velocities (wa), reflectivity and Doppler velocity, and backscatter and depolarization ratio values were used to define the size of the important dynamical structures. Ice crystal number concentration (Ni), ice water content (IWC), droplet number concentration (Nd), liquid water content (LWC) and characteristic particle size and shape were summarized for each case. Ni was found directly related to dynamical parameters e.g. wa, with large values of wa resulting in low values of NI. The variability in parameters obtained from various platforms can be attributed to their instrumental capabilities, resolution, as well as the cloud development.
