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.