Spindrift Spindrift Spindrift (more rarely spoondrift) usually refers to spray, particularly to the spray blown from cresting waves during a gale. This spray, which "drifts" in the direction of the gale, is one of the characteristics of a wind speed of 8 Beaufort and higher at sea. In Great Britain "spindrift" is the telltale sign used by mariners to define a Force 8 (Beaufort Scale) wind (not higher) when observed at sea. See this example of information provided by Lymington Harbour authority, Hampshire, England, UK, explaining the whole scale, the associated wind speeds, and its telltale signs. Text from the site
Wind gradient wind is similar to the geostrophic wind but also includes centrifugal force (or centripetal acceleration). Wind direction is usually expressed in terms of the direction from which it originates. For example, a "northerly" wind blows from the north to the south. Weather vanes pivot to indicate the direction of the wind. At airports, windsocks indicate wind direction, and can also be used to estimate wind speed by the angle of hang. Wind speed is measured by anemometers, most commonly using rotating cups or propellers. When a high measurement frequency is needed (such as in research applications), wind can be