The climate of a retrograde rotating Earth (2018)

https://www.earth-syst-dynam.net/9/1191/2018/

by otagekki • 7 years ago

29 15 7 years ago

gus_massa2• 7 years ago

In a previous post of a map of a retrograde Earth(based on this?) I notice the change of climate in Central America, and I thought it was weird.

In the real Earth there is a lot of wind from the Caribean to the Pacific that caries a lot of humidity and rain.

In a retrograde Earth, the winds in that area go from north to south, and don't have so much humidity. (I expected winds going from the Pacific to the Caribean, without a big change in humidity.) (It is still weird.)

perl4ever2• 7 years ago

The abstract confused me.

Near the beginning, it refers to "the switch in the character of the European–African climate with that of the Americas, with a drying of the former and a greening of the latter"

Later on, it says "the temperature gradient between Europe and eastern Siberia is reversed, and the Sahara greens, while large parts of the Americas become deserts"

These seem somewhat contradictory, and I'm wondering if something was inadvertently reversed.

perl4ever2• 7 years ago

aka "Velikovskian climate change"...

ncmncm• 7 years ago

This is a very surprising topic. Why should anything be different?

But it's not about rotation not matching direction of motion around the sun. It's more about how climates on the continents, as they lie, would be affected by jet streams and ocean currents which are driven by earth's rotation. They would encounter the coastlines and mountain ranges from different directions. On the real earth, for example, we see England and Norway oddly warm, equatorial Africa oddly dry, the Amazon uniquely wet. This being about fluid dynamics, every detail is unpredictable, from an armchair perspective. Some alterations seem sensible, but that sense is too frequently illusory.

gus_massa2• 7 years ago

The direction of the Trade Winds [1] is determined by the rotation of the Earth due to the Coriolis effect. They would reverse, and I guess it would cause more humidity in West Africa and less humidity in East Africa.

The effect of the big mountain range is more difficult to estimate (without a good simulation). In South America the Andes cover all the West Cost. In the South part the winds go mostly to the East, so it rains a lot in the small west past of the Andes, and there is a semi desert part in the big part to the ease of the Andes. In the North part of South America, the winds go mostly to the West, so you get a big humid part in the Amazon. If the winds are reversed, the semi desert part and the rainforest part somewhat exchange positions.

I don't understand the sea currents enough for handwaving, but a big change in the Gulf Stream [2] would make the United Kingdom much cooler.

[1] https://en.wikipedia.org/wiki/Trade_winds

[2] https://en.wikipedia.org/wiki/Gulf_Stream

labster• 7 years ago

As someone who studied meterology and paleoclimatology in university, the result seems completely obvious that a whole lot would be different if circulation was reversed. Weather is mostly large-scale turbulence, driven by the entropically irreversible phase change of water. I suspect a mild case of Dunning-Kruger effect here -- on encountering evidence, you changed your position quite quickly.

If you look at some prehistorical events, like the closing of the isthmus of Panama or the opening of the Tasmanian sea, these had a huge effect on heat flow throughout the atmosphere continents away, enough to inaugurate new geological eras, you can see how everything changes based on the shapes of the turbulence.

There are interesting things in the results though. When the wind direction switches in California now, you turn into a downslope wind driven desert with power failures. But if you reverse the flow everywhere, this study looks like it's doing some sort of eddy thing through the Gulf of Mexico, and probably driving a bunch of hurricanes to L.A. Can't really tell looking at that weird ITCZ though... but it looks like the Congo would get absolutely slammed by hurricanes in this scenario.

h2odragon• 7 years ago

Yeah sure fancy plans but how do you implement them? Just grabbing the earth to stop it is hard, and thats just half the acceleration. It turns out the planet is distressingly blobby for such geoengineering projects.

jvm_• 7 years ago

Just strap a bunch of rockets and point them to the horizon... until you realize that the earths crust isn't that deep and your rockets just end up ripping a scab of earth off and flying off into space. I guess that would be one way to make a local volcano.

HocusLocus• 7 years ago

[Mom pops down to the basement to say Hi and see what you're up to] ;-)

chrisco255• 7 years ago

Does anyone know if Earth's rotation is influenced by it's electromagnetic polarity and if shifts in rotation are possible during magnetic pole shifts?

jcranmer2• 7 years ago

Earth's rotation is almost certainly affected by the magnetic field, and I suspect a complete reverse of the field would flip the sign contribution.

But recall that there is conservation of angular momentum, and there is an awful lot of mass spinning at high speed and large radius to Earth's center of inertia. The contribution of the magnetic field to the rotation time of Earth's surface is on the order of ms, or parts per million, as the total term itself is 86.4 ks.

In comparison to the effects of things such as the orbit of the Moon, the magnetic field doesn't have enough energy to meaningfully affect the Earth's rotation.

ClumsyPilot• 7 years ago

This doesn't seem right to me, If earth were a rotating magnet in free space, it would have to interact with another magnet to experience any net force.

Also Earth magnetic field is very weak, think of how much force a compass needle has, and that's while you are standing right on the surface - it falls off with distance.

ShadowKitten• 7 years ago

dude... https://www.youtube.com/watch?v=1VPfZ_XzisU

we could be in for some serious shit

The climate of a retrograde rotating Earth (2018)

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