Niven style Ringworld weather patterns?

[Natorgator]

I recently finished reading Ringworld and Ringworld Engineers and have been wondering what the weather would be like on the ring. Since it's always high noon except at night, wouldn't it basically be summer all the time? And with so much space (a million miles wide and 3 million times the area of Earth) how much water would you need to make sure the ring world wasn't really arid?

Also with no truly deep bodies of water and no Coriolis effect, would you ever see hurricanes?

[GrandMasterTerwynn]

I recently finished reading Ringworld and Ringworld Engineers and have been wondering what the weather would be like on the ring. Since it's always high noon except at night, wouldn't it basically be summer all the time?

Yes. Weather on a ring would be bloody boring. The main driver of atmospheric circulation would be the shadow-squares . . . since these provide a rather abrupt transition between sunshine and darkness. So air would tend to warm and rise during the day, and cool and sink at night. Enough of these cycles will set up a prevailing circulation in the direction the shadow-squares are moving. So the air would move.

Over the vast, vast oceans, heating and cooling would be uniform. A ringworld of the size you're talking about would have huge oceans, with enormous heat content. The oceanic airmasses would be absolutely stable (except near the edges of the ring and the coastlines.) Days will be warm and sunny. Nights will be warm and clear (as the heat content of the oceans would tend to moderate the change in temperature with altitude.)

When these prevailing winds reach land, you'll have terrain-driven weather. Coastal mountain ranges will provide orographic lift, allowing the formation of convection. You will have coastal rainforests, where mountains are destabilizing otherwise stable, but moist, maritime air. Rainfall along the coasts will be high, until the land has wrung out all the moisture from the air. However, in the interiors of continents, it will be quite arid. You'll have mesoscale high and low-pressure systems in the interior, since land cools off faster at night, and terrain can create interesting circulation patterns . . . but they will by dry and windy, with only high clouds to mark where orographic lift has destabilized the atmosphere enough for what little moisture it holds to condense out into clouds. Otherwise, the daytime forecast will be warm and sunny, with diurnally driven winds. Nighttimes will be cool and clear with winds diminishing before 'midnight.' You'll get more unsettled weather near the rims of the world, but it will largely stabilize a couple thousand miles from the rims.

[Swindle1984]

Doesn't Ringworld describe the shadow-squares as being designed to generate lots of twilight before and after nightfall?

[Simon_Jester]

Hmm.

You could do that by having the edges of the squares be made of some kind of mesh or screen of varying density, so that when the outermost edge passes between you and the sun it blocks only, say, 10% of sunlight... but it blocks 50% of sunlight an hour later, and 90% an hour after that.

[Broomstick]

Niven covered some of this with his essay "Worlds in Flight", where, among other things, he suggests bobbing the ring up and down in relation to the sun in order to vary the seasons.

I would assume any species capable of building a ringworld would also be able to build pumps to send rivers through arid areas, or perhaps some mechanism to get water into the atmosphere for more varied weather, should they desire.

[Junghalli]

I remember from reading Ringworld that the coasts were highly irregular, with lots of bays and islands. It would be reasonable to think they'd also be highly irregular on a larger scale, with lots of small seas, islands, peninsulae etc. In fact I remember the book mentioning that the Ringworld's water was mostly in small seas, with the Great Oceans being the only really big bodies, which would fit with that. Since the terrain of Ringworld is completely artificial (with the exception of things like Fist Of God Mountain) if a wet climate were desirable the builders could easily have created an arrangement of land and water that would maximize moist maritime climates and minimize dry continental climates.

Although I wonder what this might mean for the Maps; their climates might not mirror those of the planets they're supposed to represent very well without a lot of intervention in detail.

[Swindle1984]

Niven covered some of this with his essay "Worlds in Flight", where, among other things, he suggests bobbing the ring up and down in relation to the sun in order to vary the seasons.

I would assume any species capable of building a ringworld would also be able to build pumps to send rivers through arid areas, or perhaps some mechanism to get water into the atmosphere for more varied weather, should they desire.

I remember, at least in the first book, the characters fly over a huge desert and several dry riverbeds, many of which are swept bare of soil down to the scrith material that makes up the Ringworld. But this was a result of a meteor hole affecting weather patterns, not long-term results of Ringworld climate.

[Crossroads Inc.]

This may be a bit off topic, but how would "weather" function on an enclosed habitate like an O'Neil colony? I just suddenly thought of all those paintings with immense lush forrests and rolling grass hills and realized without internal rain storms, the colonies would need the mother of all irragation systems.

[sirocco]

This may be a bit off topic, but how would "weather" function on an enclosed habitate like an O'Neil colony? I just suddenly thought of all those paintings with immense lush forrests and rolling grass hills and realized without internal rain storms, the colonies would need the mother of all irragation systems.

I think this is quite difficult to estimate. It depends on the structure of the habitat, position of water bodies and of main water consumers, distribution of temperature, and probably the most important is the air circulation. But I'm positive that thr weather won't be as simple as on Earth. You'll need to manage every parameter and its implications.

The bright side is that, except unforeseen events, you'll be able to know the exact weather at any moment of the future.

You should look into HVAC systems for better answers.

[Swindle1984]

This may be a bit off topic, but how would "weather" function on an enclosed habitate like an O'Neil colony? I just suddenly thought of all those paintings with immense lush forrests and rolling grass hills and realized without internal rain storms, the colonies would need the mother of all irragation systems.

Recalling from my O'Neill cylinder thread... There should be a more-or-less constant breeze from the spin. Temperature should be easily regulated. There would be weather, including rain, if there was enough atmospheric humidity. Sunlight is entirely controlled. Rivers and ponds would be artificial, obviously. Plantlife would process the atmosphere naturally, no need for environmental controls except inside buildings, which would double as vacuum and radiation shelters in case of solar eruptions and major/local hull breaches.