Posted: Thu May 27, 2010 5:48 am
No, it's here.patiku wrote:Here's the address.Anguipes wrote:Hey, guys, the Church of Exobiology is across the street.
WE ARE MOVING - see Ephemera
http://www.incatena.org/
No, it's here.patiku wrote:Here's the address.Anguipes wrote:Hey, guys, the Church of Exobiology is across the street.
A standard illustration summarising this for the Earth is here: http://en.wikipedia.org/wiki/File:AtmosphCirc2.pngSal wrote:1. Hot air rises on the equator, and spreads out from there
2. The hot air eventually cools, and so falls - in a different place from where it rose
3. The falling air hits the ground and spreads out, in both directions. So some of it goes back toward the tropics, some of it also goes toward the poles.
4. The air heading toward the poles is warmer than the air it meets, so eventually it rises again
5. The risen air spreads out, again in both directions - some toward the pole, some toward the tropics
6. The air going toward the tropics goes as far as meeting the falling are from stage 2, and falls with it
7. The air going toward the poles cools further and falls again. And so on.
8. This creates 'cells' in the atmosphere of circulating air. Earth has three per hemisphere, but if coriolis forces are greater there may be more (because greater deflection means the air doesn't get as far before it cools/warms)
There will be an odd number because the cells will always begin with rising air at the equator, and end with sinking air at the poles. An even number of cells would result in a pattern where air rises or falls at both ends of the cycle, which is not at all likely.Sal wrote:9a. However many cells, there will be an odd number.
Whoops Must've gotten ahead of myself. I didn't see bricka's thread until he pointed it out on the second page (wasn't aware this thread had a second page either, at first). My replies to the other posts will be on there.Anguipes wrote:Hey, guys, the Church of Exobiology is across the street.
Thanks for that link, patiku. I have joined and posted my introduction.patiku wrote:Here's the address.Anguipes wrote:Hey, guys, the Church of Exobiology is across the street.
The connection between planetary density and rotation speed (if there is one, I'm not sure) is a bit beyond what I'm discussing here. Not that I'm not interested in the answer, but I don't want to get too sidetracked.Mashmakhan wrote:Now, back on topic: What happens when a planet is smaller and has a lighter density? Will that effect the equatorial velosity and rotation speed? Will the planet have less atmospheric cells, more atmospheric cells, or will the cells just be smaller?
I think this answers my question. Thank you.Anguipes wrote:Cells sizes are proportional - you could fit the Earth in one of Jupiter's "small" cells. A small planet would have a smaller absolute size of cell, but not necessarily more cells because of it.
I assumed as much. The former having to do with rotation speed and the latter having to do with gravity. I think Geoff/bricka discusses this on his old website so I can always go back to that. And yes, I know where to find itFinal note: don't confuse equatorial rotation velocity with (equatorial) escape velocity. I'm talking about the former.
Hurricanes need a combination of warm high-pressure air and cool low-pressure air coming together at the same time to produce a massive storm. You need a lot of land area to produce the warm high-pressure air and a lot of water area to produce the cool low-pressure air. This is why you only tend to see hurricanes along the coasts of large landmasses like North America and Asia. My guess is that with a world that was mostly water but had a few tiny landmasses on it you would just get a lot of rain.vampyre_smiles wrote:Oh wow, so a planet with a lot of ocean overall, but most of the land broken into large islands might have very few hurricanes?
Ditto.eodrakken wrote:I'm still reading this too. Very useful stuff and well explained. Thanks for taking the trouble, Anguipes!
So, for this model you're ignoring the fact that low pressure areas should make the wind spiral the other way, and just doing clockwise in the north and counter-clockwise in the south? Does the change of direction in low pressure regions not make enough of a difference for this to matter?Anguipes wrote:The coriolis effect will cause winds to spiral out of high pressure zones (clockwise in the northern hemisphere, anticlockwise in the southern) and into low pressure zones (anticlockwise in the northern hemisphere, clockwise in the southern). [...]
Then, to simulate deflection from coriolis, rotate it one place clockwise in the northern hemisphere (above the rotational equator), or one place anticlockwise in the southern hemisphere
I'm not. The wind is only deflected in one direction per hemisphere and the clockwise/anticlockwise spirals are a consequence of that, not an inherent property of high and low pressure. It happens because the "arrows" point from high to low - so on the west edge of a high pressure zone the arrow points west out of the pressure system (and is then deflected, in the northern hemisphere to NW), but on the west edge of a low pressure zone the arrow would point east into the pressure system (then be deflected to the SE).eodrakken wrote:So, for this model you're ignoring the fact that low pressure areas should make the wind spiral the other way
From what I know, strong seasonal patterns [so a big axial tilt, I guess, or some other seasonal cause, like eccentricity] and a big enough continent makes sufficiently low pressure areas in the center of the continent in the summer to draw in a lot of moist air from some nearby sea. As this wet air rises it cools and no longer can hold moisture, which falls. This means summer rain.Shihali wrote:Could somebody outline the conditions for a relevant monsoon pattern to form? I have a con-continent in the tropics shaped vaguely like Africa, and I'm not sure whether it should have an important monsoon.