Atmospheric ice halos
raef 7-16 December 2002
1. Introduction
text
2. What to look for
Contents
- weather conditions
- where to look
- common halos
- coloured and white structures
- symmetry and asymmetry
- halos below the horizon
3. Ice crystals
Contents
- snowflakes
- single crystals
- plates
- rods
- pyramids
- octagons?
- clusters
- conditions of formation
- ice clouds
- windblown crystals
- can snowflakes make halo phenomena?
4. Halo families
Contents
- refractions
- reflections
- ray paths, 60deg and 90deg prisms (how we get 90deg refractions in ice))
- crystal orientations
5. How crystals fall
Contents
text
the specific orientations mean that some halos change shape and position as the sun changes altitude
6. Simulations
Contents
- history of simulating halos
- modern methods
- examples
- comparing simulations with photographs
- what we can learn from them
- what the simulations don't do
7. Rare halos
Contents
- Halos on the ground
- Unususal crystal orientations
- Unusual crystal forms
- Halos formed close to the eye
8. How to record and photograph halos
Contents
- what to take note of
- photographic techniques; exposure; masking the sun
- measuring angles
- recording time, position and conditions
- 5/li>
- 6
- 7
- 8
- 9
9. History
Contents
- ancient records in paintings/drawings
- famous displays
- who understood what was going on
- Bravais
- Tape; Greenler
- Traenkle & Pattloch
- Schroeder & Cowley
10. Forefront research
Contents
I'm not sure what should go here. I know there is some work on crystal collection from aircraft and attempts to make model (non-ice) crystals. A good place to look would be the J. of the Optical Society of America.
11. Halos on other planets
Contents
what ices casn be expected; predictions from the literature
List of illustrations
Just a few ideas for the moment. This need a lot more thought.
- Overall diagram showing what and where (Lars/Martin)
- Graphic of crystal types: example
- Photograph of crystals with scale
- Photographs of real halos (4-6 examples)
- Simulations (examples)
- Simulation/photograph comparisons
- graphics illustrating and explaining falling crystals
- non-terrestrial halos
