General Water World Weather

[gchuck]

How do you handle weather on those 90-100% water worlds? If at all?
I'm trying to flesh out a WA world, and would like to add weather with a 'thin-veneer-of-logic' (TVL).
Equatorial regions are easily into the mid-too low double digits.
Opinions sought; Are 'storms' going to be more or less prevalent/severe?

 

[Spinward Flow]

Well, one of the more recent attempts on TV was two Stargate Atlantis episodes (S01E10-11, The Storm and The Eye) that you might want to use as *a* reference point on the topic.
LINK

Try to ignore the "dramatized for TV" plot elements and just focus on the Worldwide Weather Forecasting stuff as a partial answer to your question.

 

[Enoki]

The biggest thing I've put on them relate to wave action. With little land to break up wave movement, the world's waves are often towering, sometimes cross current (waves coming in at acute angles to each other), and of varying frequency. This means when they do reach land you get things like 100 meter tsunamis one after the other, waves that make ship movement difficult or impossible, and shallower depths in the ocean a potential death trap of wave motion. Or, without tidal action due to a moon, the oceans could be relatively calm leading to little mixing (aka Titan, Saturn's moon).

I would think, atmospherically, either you have a relatively still atmosphere or one where weather moves pretty rapidly across the surface. With no land or things like mountain ranges to break fronts up they'd simply move until their energy is expended. A jet stream-like effect could be found at lower altitudes with nothing to obstruct it so there could be potential for hurricane level winds with mountainous waves whipping the surface. Or the atmosphere and water could be still, particularly if there was little temperature gradient across the planet from equator to poles.

 

[Spinward Flow]

The biggest thing I've put on them relate to wave action.

In which case, submersibles, rather than surface transport, becomes the OBVIOUS way to go in order to avoid hazardous local weather conditions.

You don't even need to submerge "that far" below the surface in order to be substantially "immune" to the wave action going on at the ocean surface.

Which then creates a curious circumstance where living UNDER the water, even if not very deep, becomes the "obvious" way to live that isn't subject to the hazards of trying to live above the water on a Water World.

 

[atpollard]

In which case, submersibles, rather than surface transport, becomes the OBVIOUS way to go in order to avoid hazardous local weather conditions.

You don't even need to submerge "that far" below the surface in order to be substantially "immune" to the wave action going on at the ocean surface.

Which then creates a curious circumstance where living UNDER the water, even if not very deep, becomes the "obvious" way to live that isn't subject to the hazards of trying to live above the water on a Water World.

… or a Cloud City once Grav-Tech arrives.

 

[atpollard]

What might be interesting is a floating cylinder “Skyscraper”. Imagine a hollow tube 200 meters in diameter and 2000 meters long with the bottom 500 meters weighted and open at the top. Now float it vertical in the ocean. Small waves will just slip around it and giant waves will just lift it and settle it back down. The buoyancy and mass will dampen the rise and fall. If it projects 500 meters out of the water (1500 meters submerged) then waves will not crest the lip or significantly tip it. It just rises and falls with the waves (just like a ship).

The inside edge of the cylinder can be lined with buildings (a skyscraper built around a central light well) and the top covered with a glass dome to keep rain out. The dome retracts to allow VTOL aircraft to land.

 

[atpollard]

How do you handle weather on those 90-100% water worlds? If at all?
I'm trying to flesh out a WA world, and would like to add weather with a 'thin-veneer-of-logic' (TVL).
Equatorial regions are easily into the mid-too low double digits.
Opinions sought; Are 'storms' going to be more or less prevalent/severe?

I would go both directions. To make things interesting, I would have a single hurricane “superstorm” that migrated across the surface driven by the jet stream. This superstorm, sucks all the bad weather from the rest of the world (the way a hurricane draws all the rain from around itself creating a calm before and after it on Earth). Thus most of the world is calm most of the time, but the Mother of all Storms with hundred meter waves and CAT 5 winds wanders the planet with a 3 day warning that it is predicted to head for your location and could last for a week or two as it passes.

 

[AlanMN]

The ttrpg Blue Planet is set on a water world. Strong tropical storms and hurricanes year round. It is set in the Serpentis system so I suspect the frequency and strength of the storms would depend on how much energy the planet receives from the central star.

 

[Enoki]

In which case, submersibles, rather than surface transport, becomes the OBVIOUS way to go in order to avoid hazardous local weather conditions.

You don't even need to submerge "that far" below the surface in order to be substantially "immune" to the wave action going on at the ocean surface.

Which then creates a curious circumstance where living UNDER the water, even if not very deep, becomes the "obvious" way to live that isn't subject to the hazards of trying to live above the water on a Water World.

Exactly. This would be the norm for a turbulent water world. For a calmer one, living on the surface of the water would be possible. With high technology and a stable atmosphere, a grav city would be an alternative.

 

[whartung]

Having weather like that would make colonizing such a world very sketchy. That's a lot to overcome right away. It's almost a "DUNE" like scenario in terms of environmental hostility. There better be something really worthwhile there to justify all the trouble.

Submersibles can certainly work (depending on what resource is being extracted). However, similarly, you could probably just do as well with a reinforced space ship that can either weather the events via straight buoyancy, or "simply" lift up and off out of trouble to a new, calmer area, or park in orbit for the storm to pass. In the end, having no actual, permanent surface installation.

 

[Enoki]

I would go both directions. To make things interesting, I would have a single hurricane “superstorm” that migrated across the surface driven by the jet stream. This superstorm, sucks all the bad weather from the rest of the world (the way a hurricane draws all the rain from around itself creating a calm before and after it on Earth). Thus most of the world is calm most of the time, but the Mother of all Storms with hundred meter waves and CAT 5 winds wanders the planet with a 3 day warning that it is predicted to head for your location and could last for a week or two as it passes.

Or you have several of these circulating in each hemisphere with the floating city able to move to avoid them. If you want more of a cyberpunk / steampunk feel the city could be made up of interlocking ships and such of various sizes that were cobbled together over time into a floating city.

Depending on government type, you might even have these at political odds with one and another.

 

[kilemall]

Having weather like that would make colonizing such a world very sketchy. That's a lot to overcome right away. It's almost a "DUNE" like scenario in terms of environmental hostility. There better be something really worthwhile there to justify all the trouble.

Submersibles can certainly work (depending on what resource is being extracted). However, similarly, you could probably just do as well with a reinforced space ship that can either weather the events via straight buoyancy, or "simply" lift up and off out of trouble to a new, calmer area, or park in orbit for the storm to pass. In the end, having no actual, permanent surface installation.

Spice-fish!

 

[Spinward Flow]

… or a Cloud City once Grav-Tech arrives.

Problem is that OTU canon (from CT) puts engineering projects such as gravitic cities into the TL=G+ range, before becoming "practical" enough to attempt (let alone succeed long enough for habitation to commence). My point being that TL=9 isn't enough to make gravitic floating cities a viable prospect.

 

[atpollard]

Problem is that OTU canon (from CT) puts engineering projects such as gravitic cities into the TL=G+ range, before becoming "practical" enough to attempt (let alone succeed long enough for habitation to commence). My point being that TL=9 isn't enough to make gravitic floating cities a viable prospect.

I am going to go out on a limb and express the opinion that something that I can design in LBB5 at TL7 should probably be possible at TL 9 … but what do I know about the infinite wisdom of the OTU.

 

[Spinward Scout]

How do you handle weather on those 90-100% water worlds? If at all?
I'm trying to flesh out a WA world, and would like to add weather with a 'thin-veneer-of-logic' (TVL).
Equatorial regions are easily into the mid-too low double digits.
Opinions sought; Are 'storms' going to be more or less prevalent/severe?

Roll 2d6
1.) Clear sky
2.) Overcast
3.) Cloudy
4.) Light Rain
5.) Heavy Rain
6.) Major Storm

 

[Grav_Moped]

@Spinward Flow & @atpollard:

Depends on how one views the term "city".

For example, Boughene Station is at least the size of six Tigress class dreadnaughts, or 3 times the upper "limit" in HG'81, with a population of at least 300,000 (but much closer to 600,000). 600,000 is a fair-sized city -- Sacramento, CA, USA, without its suburbs and such.

It's not NYC, though! Puttng even NYC on lifters that you'd expect to function for hundreds of years, is going to be a bit more complex. Now try envisioning doing that with Mumbai or Shanghai...

I mean, yeah, you could do it once you have grav tech, but not at megastructure scale. Towns? Sure. Link the towns as as an urban core and suburbs? Of course. But expect mishaps -- potentially catastrophic mishaps -- either due to weather or infrastructure failure.

At least until the tech is so routine as to pass unnoticed for decades at a time, the way streets and bridges are.

(Yes, I know there's a lot of behind-the-scenes periodic inspection and maintenance involved.)

 

[Spinward Flow]

something that I can design in LBB5 at TL7 should probably be possible at TL 9

Possible ... yes.
PRACTICAL ... not yet ... @ TL=9.

Puttng even NYC on lifters that you'd expect to function for hundreds of years, is going to be a bit more complex.

Think of the energy consumption that would require ... along with the UNINTERRUPTIBLE POWER SUPPLY that would be absolutely critical for a floating city type of megastructure to function on an enduring basis (measured in decades, minimum, with centuries being preferable).

Now compare the costs of building such a megastructure inside a planetary troposhpere NEAR the surface ... rather than building a similar sized capacity megastructure in ORBIT. The big difference being the amount of energy/power required for station keeping (low atmosphere under gravity = LOTS, in orbit beyond most of the atmosphere = remarkably little).

Consider that the energy consumption budget NEEDED to keep "a city afloat" is NOT AVAILABLE for other purposes. You're getting a service (floating above the surface) but that service isn't "producing" anything (economically speaking) aside from "slightly better environmental conditions" than if you weren't being lifted by gravitics.
Nice to have ... SURE.
NECESSARY to have in order to survive when compared to the alternatives? Not so much ...



My point being that gravitic floating cities don't start becoming "practical" until the cost of gravitics (power generation along with the gravitics systems themselves) starts dropping into the "marginal costs" range in a city's budget ... and THAT doesn't happen until TL=G+.

Yes, the tech might be AVAILABLE to do it @ TL=8-9, but it doesn't become PRACTICAL to do it until much (much!) later on down the Tech Tree.

Remember, gravitic city megastructures "are not competing in a vacuum" ... instead they are quite literally(!!) competing with similar sized megastructures that can be built IN A VACUUM @ TL=9 ... in orbit.
At that point, it's simply a lot SAFER (not to mention, cheaper!) to just build a space station (in space) and shuttle craft for transits between surface and orbit than it is to build a "grav station" in the low atmosphere and make the whole thing "float" on gravitics power.

 

[atpollard]

What percentage of Highports crash to the surface during their operational lifetimes (per OTU canon)?
What percentage of the MANY starships that land and take off from the Downport EVERY DAY crash?

… So just how common are catastrophic failures?

[On the subject of a Million Person City, all human settlements, irrespective of size, are ultimately comprised of “neighborhoods” of about 500 people maximum. It is hard-wired into human social patterns. So there is no reason the “floating city” could and would not be comprised of 500 person “modules”. This limits a catastrophic failure to less than half a Skyscraper collapse or just above a Jumbo Jet Crash.]

500 staterooms x 4 dTons = 2000 dT of living space (plus MD, PP & support infrastructure) for a ballpark size estimate.

 

[whartung]

Grav cities are an interesting topic.

Regarding the 2000 dT neighborhood, you could certainly have a collection of these structures. These structures can be soft-docked to each other using, perhaps bridges and walkways (gangways), but ones that are designed to move vs rigid mountings. The premise is that while that the structures are, in the large, stable, in the small, they "float", so it will be like connecting boats at sea together. During rough storms, it can be policy to detach the bridges. If we just state that the structures are 6 meters thick (roughly 2 stories), they work out to be about 70m square. Not quite football fields all linked together in the sky.

With TNE (FF&S), a TL9 Contra Grav unit consumes 600 of power. At TL 10 (required for thrusters), they consume 400MW. They use a guideline of 15 tons per dT for mass, so a 2000 dTon structure masses 30000 tons. Contra Grav knocks that down to "99%", so with CG on, we now have a compensate for a structure massing 300 tons.

In TNE, you need to compensate for that with thrusters, or some other technique. It's suggested in high density atmospheres that ships can become buoyant. But you still need thrusters, minimally for station keeping. TNE thrusters come in at TL10. TNE use G-turns, which is 1G of thrust for 30 minutes. 1 G-turn of fuel for 2000 dTon is 125m3. Since we need .01Gs to compensate for the Contra Grav, that's 1.25m3 per 30m, of 60m3 (almost 4 dTons) a day. This is about half of a normal railroad tank car.

So, ideally, you would spread several power plants/thrusters (as TNE thrusters are bolted to power plants) around the structure. Ideally you'd have redundant ones. So, say, if you could meet the need with 8, you'd over provision to 12 or 16 thrusters, thus allowing individual maintenance whiles the others are running. And you'd have a redundant fuel system as well.

300 tons of thrust / 8 thrusters is 37.5 tons of thrust per thruster. That's basically 2 MW of power plant. At TL 10 a 2MW fusion plant is 1m3. Times 16 thrusters (for redundancy) that 16m3 plus 400m3 for the contra grav. 416m3, 30 dtons of the structure dedicated to power just for lift.

The Contra Grav itself takes 1000m3, ~72dTons.

4 dT of fuel per day, 120 per month. With the 30, that 150, plus 72, 222 total dTons, just over 10% of structure dedicated to lift. I would recommend topping off the fuels tanks at least once a week with a shuttle (should be fast, it's not that much).

The good news is that not everything needs to be contained, it's, ideally, a habitable world that folks could be out and about on.

You'd also have lifting barges that can dock with the structures to support them in time of crisis. Single biggest risk is the Contra Grav just outright fails. That would be Bad. The overall goal is that the system not fail catastrophically and simply have a structure fall out and plunge into the surface below. That'd there'd be time to respond if necessary to support an entire structure, or at least evacuate one.

 

[Grav_Moped]

What percentage of Highports crash to the surface during their operational lifetimes (per OTU canon)?
What percentage of the MANY starships that land and take off from the Downport EVERY DAY crash?

… So just how common are catastrophic failures?

Highports can be (and probably are, on general principles) in orbit rather than levitating on grav drives, so it'd take a lot of neglect (or rather unlikely series of cascading failures) to make one literally fall before its orbital track could be returned to stability.

Starships? Not covered well, with that whole 1G M-Drive vs. up to 1.2G planetary gravity. But the game is a SF simulator, not a future-tech simulator. Accidents happen when dramatically required, and probably don't happen otherwise.

[On the subject of a Million Person City, all human settlements, irrespective of size, are ultimately comprised of “neighborhoods” of about 500 people maximum. It is hard-wired into human social patterns. So there is no reason the “floating city” could and would not be comprised of 500 person “modules”. This limits a catastrophic failure to less than half a Skyscraper collapse or just above a Jumbo Jet Crash.]

500 staterooms x 4 dTons = 2000 dT of living space (plus MD, PP & support infrastructure) for a ballpark size estimate.

Again, this depends on how you think of a city. Is it relatively horizontal, like a small town? Failures can be isolated.

Are we talking about New York City, where it'd be massively vertical as well? If the latter, what happens when the lifters in an upper-level module fail and it crashes through a few other modules on the way down?