VOLCANIC ASH DETECTOR AND WEATHER CONDITION DETERMINATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a volcanic ash detector capable of detecting a fall of volcanic ash separately from rain or snow without accumulating the volcanic ash on the surface of the detector.;SOLUTION: An irradiation part 15 is constituted so as to irradiate a measuring region 5, through which falling volcanic ash passes, with a parallel light beam and a first light detection part 16 detects a plurality of light beams (passing light beams) formed through a plurality of slits 15c wherein a plurality of horizontally long slits are vertically provided in parallel on the opposite bank after the light beam passes the measuring region 5. A second light detection part 18 detects the scattered light formed by scattering the light beam emitted from the irradiation part 15 by the particles in the measuring region 5. When the particles fall through the measuring region 5, the quantity of the passing light changes so as to be undulated by the presence of the slits 15c. Decision parts 26 and 27 calculate the presence of the particles falling through the measuring region 5 the falling speed of the particles, the particle size of the particles, the density of the particles, etc. from the quantity of passing light or scattered light, the change quantity of light, a change ratio, a change cycle, a change cycle, a waveform, etc. to detect the presence of the falling of the volcanic ash.;COPYRIGHT: (C)2008,JPO&INPIT