Abstract: A parent unit is provided having: a precedent base for accumulating data from child units; an element data determination unit for processing the data into element data; an element data classification unit for creating a classification; an element data change classification unit for determining which classification the element data belongs to, and calculates transition probabilities among the classifications, and a display unit for displaying data. The child unit collects air current data, processes the data, obtains the transition probabilities, and calculates a probability of encountering air turbulence. The child unit then displays certain data when the probability of encountering air turbulence satisfies predetermined conditions.

Abstract: A turbulent layer detecting apparatus in accordance with the present invention is equipped with a transmitting section that transmits beams of electromagnetic waves, sound waves or light waves into the atmosphere, a receiving section that receives the electromagnetic waves, the sound waves, or the light waves that have been transmitted by the transmitting section and scattered by particulates or the like in the atmosphere, a wind velocity measuring section that measures a beam direction component of a wind velocity at two or more observation points on a beam from a received signal received by the receiving section, or a density measuring section that measures a density at two or more observation points on the beam, and a turbulent layer detecting section that detects the presence of a turbulent layer on the basis of the output of either the wind velocity measuring section or the density measuring section.