PROOF COPY 519310PHF

摘要: Balloons have been increasingly attracting the interest of researchers. They have been used as scientific platforms with useful loads for experiments, space observations, and particularly for the study of the atmosphere of the Earth and other planets. The main atmospheric applications are for the study of phenomena and for in situ measurements. A relevant advantage is given by the unimprovable spatial and temporal resolutions of collected data, considering the moderate balloon speeds and the high performance of actual instruments. The highest vertical resolution for atmospheric observations, on the order of 1 m, stems from balloons. 1 Their mission success is rated among many factors by the payload weight they are able to lift, the operational altitude range, and the duration at target height with minimum excursions. Balloons fall into two basic categories: open (zeropressure) and closed (superpressure). The former have one or several openings at the base of the envelope and are therefore said to be open to the external atmosphere. The film is either filled with hot air or a gas lighter than the atmosphere. These balloons usually fly science and technology missions up to the stratosphere, lasting a few hours to a few days. They vary in volume from several thousand to over one million cubic meters and can carry payloads weighing tens of kilograms to a few tons. Their altitude can be controlled by a valve at the top of the balloon and by ballasting. A balloon responds to its environment in a complex way. Essentially, its horizontal speed mimics the ambient air, but even this simple assumption may be sometimes questioned. Its vertical motion is a …