|
Credit & Copyright: Joel Knain
Explanation:
What could create a huge hole the clouds?
Such a hole, likely hundreds of meters across, was
photographed last month from a driveway near
Mobile, Alabama,
USA.
Very unusual to see,
hole-punch clouds like this are still the topic of
meteorological speculation.
A leading hypothesis holds that the
hole-punch cloud is caused by falling ice-crystals.
The ice-crystals could originate in a higher cloud or be
facilitated by a passing airplane exhaust.
If the air has just the
right temperature and moisture content, the
falling crystals
will absorb water from the air and grow.
For this to happen, the water must be
so cold that all it needs is a surface to freeze on.
The moisture lost from the air increases the
evaporation rate from the cloud water droplets
so they dissipate to form the hole.
The now heavier ice crystals continue to fall and form the more
tenuous wispy cloud-like
virga seen inside and just below the hole.
Water and ice from the
virga evaporates before it reaches the ground.
|
January February March April May June July August September October November December |
| ||||||||||||||||||||||||||||||||||||||||||||||||
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Earth - clouds
Publications with words: Earth - clouds
See also: