| 释义 |
infralateral tangent arcs infralateral tangent arcs[¦in·frə¦lad·ə·rəl ′tan·jənt ‚ärks] (meteorology) Two oblique, colored arcs, convex toward the sun and tangent to the halo of 46° at points below the altitude of the sun, produced by refraction (90° effective prism angle) in hexagonal columnar ice crystals whose principal axes are horizontal but randomly directed in azimuth; if the sun's elevation exceeds about 68°, the arcs cannot appear. |