Wave Cloud

Is there any difference between lee waves and gravity waves?

ChatGPT said:

Yes, lee waves and gravity waves are related phenomena, but they are distinct in their context and characteristics:

1. Gravity Waves

Definition: Gravity waves are oscillations in a fluid medium (e.g., the atmosphere or ocean) where the restoring force is gravity. These waves can occur when fluid layers are displaced vertically and gravity works to restore equilibrium.
Occurrence: They occur in various settings, including atmospheric layers, oceans, or any medium where buoyancy plays a role.
Examples:
- Ocean waves created by wind.
- Atmospheric waves generated by storms or other disturbances.
- Internal gravity waves propagating within stable atmospheric layers.

2. Lee Waves

Definition: Lee waves are a specific type of atmospheric gravity wave that forms when stable air flows over a mountain or similar topographic obstacle. The obstruction forces the air to oscillate vertically, producing a wave pattern on the lee side (downwind side) of the mountain.
Occurrence: They are a subset of gravity waves that specifically arise due to the interaction of airflow with terrain.
Characteristics:
- They often result in standing waves that do not move relative to the mountain, giving them a fixed appearance.
- Associated with features like lenticular clouds, which form at the crests of the waves.
- Can produce turbulence, affecting aviation.

Key Differences

Aspect	Gravity Waves	Lee Waves
Definition	General waves caused by gravity as a restoring force.	A specific type of gravity wave caused by airflow over terrain.
Cause	Broad (e.g., buoyancy, storms, etc.).	Flow of air over topography.
Location	Atmosphere, oceans, or other fluids.	Downwind side of mountains or ridges.
Motion	Can be traveling or standing waves.	Typically standing waves.

Relationship:

Lee waves are a subset of gravity waves, specific to atmospheric conditions involving terrain-induced airflow.

December 19, 2024

Artificial Intelligence, Gravity Waves, Wave Cloud

Is there any difference between lee waves and gravity waves? Read More »

31 Oct 2024 – Wave cloud downwind of NE Scotland

A terrific display of orographic lee wave cloud across NENE North East Scotland that extends eastward into Norway. Unusually, all the LCBR across northeast Scotland are reporting zilch in terms of medium or upper cloud heights this lunchtime, so I had to revert to some Weather Watcher images as a last resort.

These Weather Watcher pictures show the base of the lenticular ACAC Altocumulus clouds are generally associated with settled weather and will normally appear white or grey with shading. Height of base: 7,000 - 18,000 ft Shape: Bands or areas of individual cells Latin: altum - height; cumulus - heap Altocumulus clouds are small mid-level layers or patches of clouds, called cloudlets, which most commonly exist in the shape of rounded clumps. There are many varieties of altocumulus, however, meaning they can appear in a range of shapes. Altocumulus are made up of a mix of ice and water, giving them a slightly more ethereal appearance than the big and fluffy lower level cumulus./CICI Cloud, comprised of ice crystals that form wispy filamentous tufted streaks or ‘mare's tails’ at high altitude usually 16,500 to 45,000 ft./CSCS Ice cloud forming a thin, more or less uniform semi-translucent layer at high altitude, usually 16,500 to 45,000 ft. cloud is very high, maybe 18,000 ft or higher by the look of it.