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Meteorology
3.4.8.2 Wind gusts and wind squalls ............................................................. 264
3.4.8.3 Veering and backing ......................................................................... 264
3.4.8.4 Windsock ......................................................................................... 265
3.5 Humidity and precipitation ..................................................................... 266
3.5.1 States of water ..................................................................................... 266
3.5.2 Air’s humidity content .......................................................................... 267
3.5.3 Vapor pressure and saturation pressure ............................................... 268
3.5.3.1 Absolute humidity ............................................................................ 269
3.5.3.2 Relative humidity ............................................................................. 269
3.5.3.3 Humidity indication in aviation ......................................................... 270
3.5.4 Stable and unstable air ......................................................................... 271
3.5.4.1 Stable, unstable and conditionally unstable air mass ........................ 271
3.5.5 Adiabatic processes .............................................................................. 273
3.5.5.1 Dry adiabatic process ....................................................................... 273
3.5.5.2 Saturated adiabatic process.............................................................. 273
3.6 Clouds..................................................................................................... 276
3.6.1 Formation of clouds .............................................................................. 276
3.6.1.1 Condensation level ............................................................................ 276
3.6.2 Clouds - types ....................................................................................... 278
3.6.2.1 Strato – low-level clouds .................................................................. 278
3.6.2.2 Alto – middle-level clouds ................................................................ 279
3.6.2.3 Cirro – high-level clouds ................................................................... 279
3.6.2.4 Nimbus – precipitation clouds .......................................................... 280
3.6.3 Formation of clouds .............................................................................. 281
3.6.3.1 Convective clouds............................................................................. 281
3.6.3.2 Front clouds / advection clouds ........................................................ 281
3.6.3.3 Orographic clouds ............................................................................ 282
3.6.4 Cumulonimbus cloud ............................................................................ 281
3.6.4.1 Condition for the growth of a CB cloud ............................................. 283
3.6.4.2 Development of a CB cloud .............................................................. 284
3.6.5 Wind gradient and wind gust during takeoff and landing ...................... 285
3.6.5.1 Indication of cloud amount............................................................... 286
3.6.6 Fog ....................................................................................................... 286
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© marts 2026 209
