Peter, T. H. and Luo, B. P. and Wernli, H. and Wirth, M. and Kiemle, C. and Flentje, H. and Yushkov, V. A. and Khattatov, V. and Rudakov, V. and Thomas, A. and Borrmann, S. and Toci, G. and Mazzinghi, P. and Beuermann, J. and Schiller, C. and Cairo, F. and Didonfrancesco, G. and Adriani, A. and Volk, C. M. and Ström, J. and Noone, K. and Mitev, V. and Mackenzie, A. Robert and Carslaw, K. S. and Trautmann, T. and Santacesaria, V. and Stefanutti, L. (2003) Ultrathin tropical tropopause clouds: I. Cloud morphology and occurrence. Atmospheric Chemistry and Physics, 3 (4). pp. 1083-1091.
Full text not available from this repository.Abstract
Subvisible cirrus clouds (SVCs) may contribute to dehydration close to the tropical tropopause. The higher and colder SVCs and the larger their ice crystals, the more likely they represent the last efficient point of contact of the gas phase with the ice phase and, hence, the last dehydrating step, before the air enters the stratosphere. The first simultaneous in situ and remote sensing measurements of SVCs were taken during the APE-THESEO campaign in the western Indian ocean in February/March 1999. The observed clouds, termed Ultrathin Tropical Tropopause Clouds (UTTCs), belong to the geometrically and optically thinnest large-scale clouds in the Earth's atmosphere. Individual UTTCs may exist for many hours as an only 200--300 m thick cloud layer just a few hundred meters below the tropical cold point tropopause, covering up to 105 km2. With temperatures as low as 181 K these clouds are prime representatives for defining the water mixing ratio of air entering the lower stratosphere.