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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© 2025 209
