A097403 Minimum wind speed in knots for Beaufort Number n.

0, 1, 4, 7, 11, 17, 22, 28, 34, 41, 48, 56, 64

Offset

0,3

Comments

The indices of this sequence, Beaufort Numbers 0 through 12, originally (in 1805) represented different categories of wind force and their effects on a "well-conditioned man-of-war" (Admiral Beaufort's type of ship). Only later were specific ranges of wind speeds attached to the force numbers. The World Meteorological Organization has associated a brief descriptive name to each Beaufort Number (see NWS link); for example, 0=Calm, 8=Gale, 10=Storm, 12=Hurricane. The Met Office link indicates that this scale was extended in 1944 to Beaufort Number 17 and 118 knots; 13 through 17 are only intended to be used for special circumstances such as tropical cyclones. The extension limits the definition of Force 12 to no more than 71 knots. (Most sources I've seen list only Beaufort Numbers 0 through 12 so I'm attaching keyword "full" here.)

Links

Table of n, a(n) for n=0..12.

Met Office, The Beaufort Scale.

National Weather Service - Portland, Beaufort Wind Scale.

R. Rowlett, Beaufort Scales (Wind Speed).

Example

a(8) = 34 because Beaufort Number 8 (Wind Force 8 of the Beaufort Scale, a gale) corresponds to 34 knots up to a(9)-1 = 40 knots of wind speed.

Crossrefs

Cf. A097404 (same, in statute mph).

Sequence in context: A038835 A360138 A310766 * A126618 A171452 A049648

Adjacent sequences: A097400 A097401 A097402 * A097404 A097405 A097406

Keyword

fini,full,nonn

Author

Rick L. Shepherd, Aug 14 2004

Status

approved