Orographic precipitation

Seeder And Feeder Clouds

Orographic precipitation is commonly regarded as a distinct type, but this requires careful qualification. Mountains are not especially efficient in causing moisture to be removed from airstreams crossing them, yet because precipitation falls repeatedly in more or less the same locations, the cumulative totals are large. An orographic barrier may produce several effects, depending on its alignment and size. They include 1 forced ascent on a smooth mountain slope, producing adiabatic cooling,...

The centripetal acceleration

Surface Friction Coriolis Wind

Observations in the free atmosphere above the level affected by surface friction up to about 500 to 1000 m show that the wind blows more or less at right angles to the pressure gradient i.e. parallel to the isobars with, for the northern hemisphere, high pressure on the right and low pressure on the left when viewed downwind. This implies that for steady motion the pressure-gradient force is balanced exactly by the Coriolis deflection acting in the diametrically opposite direction Figure 6.3A ....