Helicopter-Borne Radiosonde System and Its Experimental Uses

[摘要] A helicopter-borne radiosonde system is developed to determine thermal structures of the lower atmospheric layer. It consists of a radiosonde instrument, a winch, a receiver with a receiving antenna and a recorder. An on-board winch hangs down the radiosonde instruments from a hovering helicopter and winds it, up with a nylon cord tied at the top of the instrument, to the helicopter again after measurements. Radiosonde sensors attached to or packed in a metalic watertight cylindrical vessel can measure dry- and wet-bulb temperatures and pressure, and detect also water temperature when it alights on the water. Measurement signals are transmitted from the radiosonde instrument to an on-board receiver. Easy and rapid movement of a helicopter from place to place makes it possible to measure (1) vertical profiles of the dry-and wet-bulb temperatures above any target site by making a helicopter to hover at given height and (2) horizontal distributions of dry- and wet-bulb temperatures along a prescribed path of a flying helicopter suspending the radiosonde instrument at a given height. Correction of surface temperatures remotely-sensed by means of a helicopter-borne infrared thermographical instrument at the height of about 300m for absorbing and emitting effects of atmospheric water vapor is carried out as an application of the radiosonde system to indicate that reduction of temperatures due to effects of water vapor is several degrees Centigrade. Another example is also shown.

[学科分类] 大气科学