{"id":9529,"date":"2024-09-08T11:00:46","date_gmt":"2024-09-08T03:00:46","guid":{"rendered":"https:\/\/tommykwan.com\/blog\/?p=9529"},"modified":"2025-07-20T21:37:27","modified_gmt":"2025-07-20T13:37:27","slug":"clouds-%e9%9b%b2","status":"publish","type":"post","link":"https:\/\/tommykwan.com\/blog\/aviation\/clouds-%e9%9b%b2\/","title":{"rendered":"Clouds \u96f2"},"content":{"rendered":"

Ref: https:\/\/cloudatlas.wmo.int\/en\/clouds.html<\/a><\/p>\n

\u96f2\u4fc2\u4e00\u7a2e\u540c\u6c34\u6709\u95dc\u65e2\u5927\u6c23\u73fe\u8c61<\/p>\n

A cloud is a\u00a0hydrometeor<\/a>\u00a0consisting of minute particles of liquid water or ice, or of both, suspended in the atmosphere and usually not touching the ground. It may also include larger particles of liquid water or ice, as well as non-aqueous liquid or solid particles such as those present in fumes, smoke or dust.<\/p>\n

 <\/p>\n

Distinguish clouds by levels<\/strong><\/span><\/h3>\n

Clouds<\/strong> are generally encountered over a range of altitudes varying from sea level to<\/strong> the top of the troposphere<\/strong> (i.e the tropopause).<\/p>\n

<\/p>\n

Table 6. Approximate heights of each level, and the genera occurring in each. (Information from WMO)<\/strong><\/p>\n

\n\n\n\n\n\n\n
Level<\/em><\/td>\nGenera<\/em><\/td>\nPolar<\/strong> region<\/em><\/td>\nTemperate<\/strong> region<\/em><\/td>\nTropical<\/strong> region<\/em><\/td>\n<\/tr>\n
High<\/strong><\/td>\nCirrus
\nCirrocumulus
\nCirrostratus<\/td>\n		3 \u2013 8 km
\n(10 000<\/strong> \u2013 25 000 ft<\/strong>)<\/td>\n		5 \u2013 13 km
\n(16 500 \u2013 45 000 ft<\/strong>)<\/td>\n		6 \u201318 km
\n(20 000 \u2013 60 000 ft<\/strong>)<\/td>\n<\/tr>\n
Middle<\/strong><\/td>\nAltocumulus
\nAltostratus
\nNimbostratus<\/td>\n		2 \u2013 4km
\n(6 500<\/strong> \u2013 13 000 ft)<\/td>\n		2 \u2013 7 km
\n(6 500 \u2013 23 000 ft)<\/td>\n		2 \u2013 8 km
\n(6 500 \u2013 25 000 ft<\/strong>)<\/td>\n<\/tr>\n
Low<\/strong><\/td>\nStratus
\nStratocumulus
\nCumulus
\nCumulonimbus<\/td>\n		From the Earth\u2019s surface to 2 km
\n(0 \u2013 6 500ft<\/strong>)<\/td>\n		From the Earth\u2019s surface to 2 km
\n(0 \u2013 6 500ft)<\/td>\n		From the Earth\u2019s surface to 2 km
\n(0 \u2013 6 500ft)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Most clouds are confined within their level with the following\u00a0few notable exceptions:<\/p>\n

(a) Altostratus is usually found in the middle level, but it often extends higher;<\/p>\n

(b) Nimbostratus (Ns)<\/span> is almost always found in the middle level<\/span>, but it usually extends into the other two levels;<\/p>\n

(c) Cumulus and Cumulonimbus (Cb)<\/span> usually have their bases in the low level<\/span>, but their vertical extent is often so great that their tops may reach into the middle and high levels.<\/p>\n

When the height of a particular cloud is known, the concept of levels may be of some help to the observer in identifying the cloud. The genus can be determined by making a choice from among the genera normally encountered in the level corresponding to its height.<\/p>\n

 <\/p>\n<\/div>\n

Distinguish clouds by Genera<\/strong><\/span><\/h3>\n

Consideration of the most typical forms of clouds leads to the recognition of (10) ten genera<\/strong><\/span>. The definitions of the genera given below do not cover all possible aspects, but are limited to a description of the main types and of the essential characteristics necessary to distinguish a given genus from genera having a somewhat similar appearance<\/strong>.<\/p>\n

High level: Ci, Cs, Cc
\nMedium level: As, Ac, Ns
\nLow level : Sc, St, Cu, Cb<\/p>\n

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  1. Cirrus (Ci)<\/a> – High level\n