calm(redirected from calms down)
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a condition of little or no wind. On the Beaufort scale, wind velocity during a calm is 0–0.2 m/sec. Calms are usually observed within stable anticyclones, in cols, and in the intertropical convergence zone. Calms occur more often in valleys and basins than in open areas with free circulation of air. There is little turbulence during a calm, and therefore harmful atmospheric aerosols (smoke and gas) may accumulate in the lowest atmospheric layer.