What will the weather system like if Earth didn't rotate?

[Cesrate]

Well, I guess some features in major climate belt may disappear...

Edit: Oops, I forgot the sun... I just wanna ask the Coriolis effects as K^2 said.

Edited May 28, 2013 by Cesrate

[Flixxbeatz]

-snip-

oops.

Edited May 28, 2013 by Flixxbeatz

[gmpd2000]

Nothing Here

Wait, What?

Edited May 28, 2013 by gmpd2000

[Flixxbeatz]

Wait, What?

wrong thread, sorry please unquote

[WestAir]

I'd imagine it would be relatively the same short of the effects caused by the coriolis(so) effect and centrifugal force.

[GROOV3ST3R]

I wouldn't be the same.

The wind would blow from the poles towards the equator - so in the North, all wind would go to the South and in the South all wind would go to the North. That would change how everything else heats up and most likely kill off a lot of species in the process - as every major change does

UK would probably get a climate closer to that of Moscow.

[K^2]

What do you mean "didn't rotate"? If it faced the Sun with the same side all the time, there wouldn't really be much of weather at all. Just tremendous winds blowing along the surface across the day/night terminator. The sun-ward side would be close to 150°C generating major thermal updrafts. Most of the water would be accumulated as mountains of ice on the night side. Liquid water would only exist underneath all that ice due to tremendous pressure. Atmosphere would be a mix of carbon dioxide and nitrogen and quite a bit thinner than it is now.

If the Earth really had zero angular momentum, then it would have a 1 year long day-night cycle. That wouldn't be quite as bad, but pretty close. The most interesting consequence is that you'd have liquid water on the surface. Water released from melting ice on the "morning side" would be blown to the day side by the aforementioned winds. Now, there is not enough energy in sun light released over the year to boil away all of that water. So the temperatures will only reach boiling in a very small region if at all. This means the temperatures well under 100° through most of the day side, and that means atmospheric pressure would probably be much closer to what we have now, with composition dominated by nitrogen gas. Water vapor carried by upper atmosphere to he night side would also form quite fantastic clouds and rather powerful blizzards once all that moisture is brought down. This I might actually call weather.

Finally, we can look at one more possibility. Suppose, Earth orbited a much colder Sun at such a close proximity that it had a "year" that is comparable to our day in duration. Then it could have day-night cycle comparable to ours without rotating. Of course, this situation can't last very long, as an object orbiting that close to a star would quickly become tidally locked, but until that happens, such a planet would have weather patterns very similar to our own. The only effect that's missing is the Coriolis effect, and it's not that important for the weather. Mostly, you'd lose prevailing winds. So no Westerlies or Trade winds. Coriolis effect also helps form cyclones. Note that we'd still have these. We'd just end up having about an equal number of clockwise and counter-clockwise cyclones in both hemispheres. That can lead to some interesting phenomena whenever two cyclones rotating in opposite directions would happen to collide. But otherwise, the weather would be much the same.

P.S. Note, I'm not saying the climate would be the same. GROOV3ST3R's note is valid for that last scenario. Changes in wind patters would certainly shift climate zones about.

Edited May 28, 2013 by K^2

[WestAir]

I wouldn't be the same.

It was a tongue-in-cheek joke. Just like my post said, the lack of a Coriolis effect would remove the existence of the westerlies and drastically change the currents (both sea and air) and the jet stream.

The wind would blow from the poles towards the equator - so in the North, all wind would go to the South and in the South all wind would go to the North. That would change how everything else heats up and most likely kill off a lot of species in the process - as every major change does

Other way around. If the Earth didn't rotate (but day-night cycles and the moons relative orbit didn't change) the winds would flow from the equatorial regions towards the poles. I know what you're originally thinking, that because warm air rises the air at the equator would rise up, sucking colder air from the poles towards it, but if you look at a map of the westerlies you'll notice that winds actually start out blowing away from the subtropical ridge and towards the mid-latitudes. They are obviously then turned by the Coriolis effect (So they blow from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere.) If you're referring to the fact that the winds at the poles would initially move towards the equator, they already do now - check that map of the westerlies one more time. In that regards, nothing would change.

What do you mean "didn't rotate"?

I imagine the OP meant "what if the Earth stopped rotating, but the day/night cycle and the gravitational effects caused by the moon remained unchanged." At least that's what I assumed. Could totally be wrong though!

Edited May 28, 2013 by WestAir

[K^2]

I thought I remembered something about there being multiple cells of high/low. I wasn't quite certain if that was the cause for Westerlies, though. Good picture to have in mind. Thanks, westair.

[Brotoro]

No, I think GROOV3ST3R and K^2 are correct about the pole-to-equator direction of the surface winds on a non-rotating planet. Such a planet would have a single Hadley cell per hemisphere in the north-south direction carrying the hot air that rises at the equator to the poles. The return flow of the cooler, denser air from the poles will cause the surface winds to go from pole to equator. Venus exhibits this effect due to its very slow rotation. On Earth, the air that rises at the equator does not make it all the way to the poles because the coriolis force breaks the meridional flow up into multiple Hadley cells, and we get the zonal surface winds shown in the diagram above.

Edited May 28, 2013 by Brotoro
Fixed names

[WestAir]

Okay, so I now have three people telling me that I'm wrong. Obviously, that means either I'm really smart, or have no idea what I'm talking about. In this case, the later is true.

I looked up some scholarly information on the subject and got to some information written by Nathan Gasser from the University of Tennessee. He gave a pretty detailed answer to the OP's question. Here's the link: http://csep10.phys.utk.edu/astr161/lect/earth/coriolis.html

The most relevant quote here is this one:

"If solar heating were the only thing influencing the weather, we would then expect the prevailing winds along the Earth's surface to either be from the North or the South, depending on the latitude. However, the Coriolis force deflects these wind flows to the right in the Northern hemisphere and to the left in the Southern hemisphere. This produces the prevailing surface winds illustrated in the adjacent figure."

Indeed I had no idea what I was talking about. Winds would flow from the poles to the equator because the warm air will rise and leave a low pressure area the colder air will flow to along the surface. I really apologize for that one K^2 & GROOV3ST3R. You both were perfectly right.

[jeti140973]

I would expect that the event that made it stop rotating had a bigger effect than the non-rotation itself :-).

Anyone know if rotation is a prerequisite for an atmosphere/weather system to develop? I mean, we don't have empirical data from anywhere, do we?

[K^2]

Anyone know if rotation is a prerequisite for an atmosphere/weather system to develop? I mean, we don't have empirical data from anywhere, do we?

Again, what do you mean by rotation? Coriolis force doesn't seem to be necessary. It contributes, but we can have weather without it. Uneven heating is crucial however. And no, we don't have any empirical data for planets with one without the other. How could we?

[jeti140973]

Again, what do you mean by rotation? Coriolis force doesn't seem to be necessary. It contributes, but we can have weather without it. Uneven heating is crucial however. And no, we don't have any empirical data for planets with one without the other. How could we?

I meant any kind of rotation - if any type of rotation is a prerequisite for an atmosphere/weather system that would be enough of an answer for me. Then the OPs question would become invalid for *that* type of rotation, at least. And the question about empirical data was not just meant as a question - also a subtle hint that we may not yet be able to answer this without a large amount of speculation, as is often the case with counterfactional conditionals. But until then, if all known bodies with atmosphere/weather seem to rotate (somehow), then it seems fair to assume that rotation may well be a prerequisite or consequence. If science suggest otherwise, then we will know for certain when we eventually find an example.

[ncc1912]

This is a very interesting thread and, as a professional “weather guesserâ€Â, I love to read theories on this; too bad this thread seems to have lost steam a few months ago.

If you don’t mind, I’d like to go back to the original poster (OP) so we can establish some basic assumptions. The question was, "What [would] the weather system [be] like if Earth didn't rotate?" This is the assumptions I take away from this hypothetical scenario:

1) The Earth is still revolving around the Sun at the same angular velocity. It would have to or the Earth would either escape the Sun's gravity and "fly" out into space or be "sucked" in by it and burn up.

2) The Earth is still on a 23.5° tilt relative to its orbital plane. No indication to the contrary.

3) Average gravitational force on Earth is still 1g at the surface. Why would you assume otherwise?

First, I’m pretty sure most of you are correct: if the Earth stopped spinning there would be no more Coriolis effect. However, this is a symptom of a much more important change that would occur… the lack of centrifugal force. Centrifugal force is the only reason we have oceans at the equator. Learn more… Witold Fraczek’s ArcGIS model and article are a basis for what follows.

Coriolis “effect†is the basis for the perceived (or relative) direction of the winds across the planet’s surface and the direction of rotation of both migratory (baroclinic) and semi-permanent (barotropic) pressure systems, but it has only an incidental effect on the wind and in no way causes it. On Earth at least, the one true source of the wind will always be the Sun. This is why you have a semi-permanent low pressure at the equator known as the Intertropical Convergence Zone (ICZ), where the southeasterly winds from the Tropic of Capricorn converge with the northeasterly winds from the Tropic of Cancer. Since Coriolis is strongest at the equator, this is where the cyclonic turning of pressure systems is going to be the strongest and most frequent, hence tropical storms, hurricanes, typhoons, etc. What direction does the tropics flow? That’s right, west… with the Sun. The air then ascends the column of the atmosphere

But remember, the “perceived†direction is incidental to the Earth’s rotation. If Earth rotated in the opposite direction, the winds would be in the opposite direction, even if somehow the Earth revolved around the Sun parallel to its axis as opposed to perpendicular to it. I’m pretty sure Coriolis would “trump†thermodynamics in that scenario. Besides, the Sun has easterly ecliptic movement across celestial sphere.

I digress. Back to the question at hand: In the absence of Coriolis, atmospheric thermodynamics would dictateâ€â€essentiallyâ€â€the wind will always follow the primary heat source. Or, in other words flow toward the sun where low-pressure would be formed at the surface (of the Earth) and the air would ascend into the upper troposphere, cool and descend into a surface high-pressure on the other side of the planet.

But, remember Fraczek’s article; the absence of centrifugal causes the oceans to recede toward the greatest gravity, the poles. So, the poles are now covered by water/ice and the equator is now all bare land. This means the poles would be moderately warm (as the massive body of water would significantly moderate the temperature) with whipping winds always toward the direction of the sun-lit side of the planet (factoring in surface friction with topography, vegetation etc.).

So, with all this given information, I think I can deduce some conclusions:

1) Latitudes, in reference to a geographic equator, likely won’t matter to anyone anymore with regard to weather.

2) I believe, one of the most notable differences would be, since the Sun has easterly ecliptic movement across celestial sphere, the Sun would appear to traverse the sky from west to east at about 1° every 24 hours as perceived from any given point on the Earth’s surface near the orbital plane. Have lots of sunscreen!

3) “Solstice extremesâ€Â. Near the waterless equator, in what we currently call “the tropicsâ€Â, there is likely to be an arid wasteland about 3,000 km wide along a line from roughly 23.5° N (northern extreme) on one side of the planet to 23.5° S (southern extreme) on the other side along the orbital plane. This region would see virtually no rainfall/snowfall year-round.

4) There would be a massive semi-permanent cold-core high pressure center (continental polar air mass) on the dark side and a warm-core low (continental tropical air mass) on the sun-lit side that circumnavigate the Earth every year along the orbital plane.

5) There would be an almost constant band of weather from 15° N or S of the orbital plane to the northern and southern coastline and this would be where most life would exist.

6) There would still be seasons, albeit quick and devastatingly drastic (near the orbital plane) to slow and virtually indistinguishable (at the Tropics opposite the “solstice extremeâ€Â).

7) Along the orbital plane, summer would be uninhabitably hot and dry, and winters unimaginably cold, but just as dry. Picture a moon-like environment with a very fine powder like dust on the ground. In the spring and fall it would be plagued with duststorms and howling winds toward the subsolar point (the point on the Earth’s surface directly below the Sun’s zenith). At the subsolar point (and the point opposite, on the winter “dark sideâ€Â), winds would be dead calm as in the “eye of a stormâ€Â.

8) Winter on the continent would see no virtually no clouds or precipitation since the prevailing winds would be from the orbital plane and there would be no significant moisture source region in that direction, besides large lakes (i.e. lake-effect snow).

9) The northern and southern poles would still have their “bright†summers and “dark†winters.

10) Polar ice caps (if any) would be small and migrate around the poles.

11) Weather would be most extreme where the greatest thermal contrast is. In this case north of the northern solstice extreme along at Tropic of Cancer and south of the southern extreme at the Tropic of Capricorn toward closest respective circumpolar ocean… and likely in the spring and fall.

[Khrissetti]

If the Earth stopped rotating, I suspect the weather would be the least of our problems... enjoy your nine hundred mile-an-hour hop to the east...

[Tommygun]

National Geographic did a one hour show on this topic you might be interested in?

http://www.youtube.com/watch?v=w8SaPPV4Ov4