Beaufort Scale of Wind  蒲福風(fēng)級(jí)表

?

Beaufort Scale  Description  Wind speed(knot)

0         Calm 無風(fēng)                     <0
     Sea like a mirror

1        light air 軟風(fēng)                  1-2
Ripples but without foam crests

2       Light breeze 輕風(fēng)           3-6
Small wavelets. Crests do not break

3       Gentle breeze 微風(fēng)        7-10
Large wavelets. Perhaps scattered white horses

4    Moderate breeze  和風(fēng)      11-15
Small waves. Fairly frequent white horses

5    Fresh breeze 清風(fēng)            16-20
Moderate waves, many white horses

6    Strong breeze 強(qiáng)風(fēng)          21-26     
Large waves begin to form; white foam crests,probably spray
                                                               
7    Near gale   疾風(fēng)              27-33
Sea heaps up and white foam blown in streaksalong the direction of the wind


8      Gale 大風(fēng)                     34-40
Moderately high waves, crests begin to break into spindrift


9      Strong gale  烈風(fēng)          41-47
High waves. Dense foam along the direction ofthe wind. Crests of waves begin to roll over. Spray may affect visibility


10       Storm  狂風(fēng)               48-55
Very high waves with long overhanging crests. The surface of the seatakes a white appearance. The tumbling of the sea becomes heavy and shocklike. Visibility affected


11     Violent storm  暴風(fēng)      56-63
Exceptionally high waves. The seais completelycovered with long white patches of foam lying inthe direction of the wind. Visibility affected


12    Hurricane  颶風(fēng)              ≥64
The air is filled with foam and spray. Sea completely white with driving spray. Visibility very seriously affected

蒲福風(fēng)級(jí)（Beaufort scale）是國際通用的風(fēng)力等級(jí)，由英國人弗朗西斯·蒲福（Francis Beaufort）于1805年擬定，用以表示風(fēng)強(qiáng)度等級(jí)。風(fēng)力等級(jí)簡稱風(fēng)級(jí)，是風(fēng)強(qiáng)度（風(fēng)力）的一種表示方法，故又稱“蒲福風(fēng)力等級(jí)表”。它最初是根據(jù)風(fēng)對(duì)地面物體或海面的影響大小分為0—12級(jí)， 共13個(gè)等級(jí)。 自1946年以來，風(fēng)力等級(jí)又作了擴(kuò)充，增加到18個(gè)等級(jí)（0—17級(jí)）。蒲福風(fēng)級(jí)表最開始時(shí)只運(yùn)用于海上，經(jīng)改良后也可用于陸地。1947年第12屆國際氣象臺(tái)長會(huì)議上被正式承認(rèn)。