抄録
This paper clarifies a method to predict clear air turbulence (CAT) using the 6-7 micron infra-red image data taken from satellite. The existence of CAT could be estimated, when it is accompanied by clouds. But, there is no way of foreseeing it, when it is accompanied by no cloud.
As for the prediction method of CAT, two ways have been considered. One is a radar method, and another is a method using an infra-red sensor instrument. The former principle is to detect the density difference of water vapor along the CAT layer using high power radar. The later is to detect the density difference of water vapor at the front of the aircraft using a pair of infra-red sensors. However, these methods are not capable of observing the CAT uniformly in the wide aviation area.
Proposed method here is a technique to predict the CAT existence by observing the vertical vibration of water vapor by infra-red observation from satellite, upon the knowledge of the hydrodynamics.
CAT is caused from two main reasons, i.e., jet stream and mountain wave. Position of CAT appearance due to jet stream can be determined relatively to the core position. Jet stream observation by the 6-7 micron infra-red image has been reported already.
Position of CAT caused with mountain wave can be determined relatively also from the mountain wave pattern. This paper shows that mountain wave length and amplitude in clear sky can be detected from the 6-7 micron water vapor image.
Besides, when it is accompanied by clouds, the lower atmospheric wave can be observed simultaneously using the 10 micron infra-red image. Namely, this presents us a vertical profile of mountain wave.
Three examples of mountain wave in the clear sky which may involve the CAT are exhibited here from MOS-1/VTIR data. A direct proof of vertical vibration of the atmosphere was obtained by the observation of the jet trail in the layer.
