Corona-producing ice clouds: A case study of a cold mid-latitude cirrus layer
- University of Utah, Salt Lake City, Utah 84112 (United States)
- Desert Research Institute, Reno, Nevada 89506 (United States)
- University of North Dakota, Grand Forks, North Dakota 58202 (United States)
A high (14.0-km), cold ({minus}71.0thinsp{degree}C) cirrus cloud was studied by ground-based polarization lidar and millimeter radar and aircraft probes on the night of 19 April 1994 from the Cloud and Radiation Testbed site in northern Oklahoma. A rare cirrus cloud lunar corona was generated by this 1{endash}2-km-deep cloud, thus providing an opportunity to measure the composition {ital in situ}, which had previously been assumed only on the basis of lidar depolarization data and simple diffraction theory for spheres. In this case, corona ring analysis indicated an effective particle diameter of {approximately}22 {mu}m. A variety of {ital in situ} data corroborates the approximate ice-particle size derived from the passive retrieval method, especially near the cloud top, where impacted cloud samples show simple solid crystals. The homogeneous freezing of sulfuric acid droplets of stratospheric origin is assumed to be the dominant ice-particle nucleation mode acting in corona-producing cirrus clouds. It is speculated that this process results in a previously unrecognized mode of acid-contaminated ice-particle growth and that such small-particle cold cirrus clouds are potentially a radiatively distinct type of cloud. {copyright} 1998 Optical Society of America
- DOE Contract Number:
- FG03-94ER61747
- OSTI ID:
- 642460
- Journal Information:
- Applied Optics, Vol. 37, Issue 9; Other Information: PBD: Mar 1998
- Country of Publication:
- United States
- Language:
- English
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