matter circulation on roshar; some predictions and deductions

[king of nowhere]

I was just doing some calculations about the highstorms and the kind of movement of water required. probably someone already did it, but what the hell, I'd rather do it again than look all the archives.

first, about their frequency. in one of young kaladin's flashback, he remarks that many people like the weepings because there are less highstorms than usual, only one in the middle of the 4 weeks period. a rosharan weeek is 5 days, so the weepings grant 10 days without storms, which is longer than usual. an average of one highstorm per week seems a reasonable approximation. the storms cover all the continent, and they bring rain. not just any rain, but crem-filled rain. normal rain comes from water evaporation, but how the crem did end up in the stratosphere? It has to be seawater going up bringing the crem with it. therefore, it is likely that in the origin of the storms, whatever is there, there will also be a huge column of water rising from the sea.

Every cm of rain is 10 liters per square meter, which is 10000 cubic meters of water per square km. even if roshar is smaller than earth, it cannot be THAT smaller. the continent of roshar is bound to take a few tens of millions of square km, meaning that even with the extremely conservative estimates of 10 Mkm^2 (that's not even the surface of russia alone) of land and 1 cm of rain per storm there are one hundred billions cubic meters of water rising up once per week. then times that much seems more likely.

with 20 hours-day and 5 days-weeks, it means that to support one highstorm per week there must be several millions cubic meters of water rising into the air every second. While this is not as big a number as I initially assumed, and it may not be enough to generate a significant current directed towards the origin (for comparison, the gulf stream is about 30 million cubic meters per second; the antartic circumpolar current, the strongest current on earth, is 125 million cubic meters per second), it is still enough for the column on the origin to be quite big. Also, it could easily be understimated by a factor of 10, in which case it would be a very large current with a strong influence on all oceanic circulation

Notice that roshar also experience normal rain from water evaporation; I don't remember ever seeing it in the book outside of the highstorms, but if there was no rain outside of the weeping, they wouldn't have a word for rain; just as they don't have a word for "noble" that do not imply clarity of eyes. I can't find data for how much it rains on our planet, the closer I can find is that all the rivers combined carry roughly one million cubic meter per second. since some of the water is going to evaporate before reaching a river, it's safe to assume that the total rain falling over landmasses is between 1.1 and 2 million cubic meters per second. Roshar has a similar average temperature to our planet, so a similar rate of water evaporation, but being smaller it will experience less overall rain (the same average amount of rain per unit of area). So, most of the water on roshar falls in the highstorms.

 

Time for some conclusions:

1) All that water must flow back to the sea, and it must do so quite efficiently. roshar must have huge rivers. if they aren't on the surface, they must be underground (also implied by the way the shattered plains don't fill with rainwater).

2) all those continuous storms must wear down the land. crem deposition will at least partially compensate that, but it seems reasonable that there is a net loss of material. More important, if there was a net accumulation of crem, then the amount of crem suyspended in seawater would decrease over time.

therefore, roshar must be geologically very active, so that the continents can uplift quickly enough to compensate erosion.

on earth we have the phosphorous cycle, where the phosphorous from dead organisms get dissolved in water, carried by rivers to the sea, it depositates behind the sea as phosphatic rocks, and is then uplifted by tectonic forces and brought out of the sea where living organisms can access to it again. crem must undergo a similar cycle on roshar, but quicker becase of the greater rain. In fact, crem is almost certainly rich in phosphorous.

2b) This would imply big volcanoes and heartquakes on roshar, which we haven't seen so far. so either we never had a chance to see them, or there is another explanation for how the crem that sedimentate on the bottom of the ocean can come back in the cycle, or the actual situation on roshar isn't sustainable in the long term.

3) there must be a big column of water rising into the air at the origin of the storm

4) there must be  an oceanic current bringing water to the origin. that current may vary in strenght from "just one among many others" to "strong enough that an industrialized roshar would have infinite electricity just by putting tidal generators over its course".

Now that I think about it, all that water falling from the sky must have HUGE potential for hydroelectric energy.

 

One last idea, it is possible that the origin don't drain water at a constant rate. in such case, periods of increased or decreased activity would continuously alter the oceanic currents. since currents carry lots of heat and are a huge influence on local climate (new york and naples are at the same latitude, but thanks to the gulf stream you can sometimes sunbathe in the second while it's snowing in the first), randomly shifting oceanic currents may explain why seasons are erratic.

And if brandon tought about all of that during worldbuilding, I must go kneel in front of him to pay homage to his thoroughness.

Edited November 26, 2013 by king of nowhere

[Two McMillion]

One thing to remember is that not all of the land gets the highstorms.

[Arook]

One thing to remember is that not all of the land gets the highstorms.

 

Also the storms are at least a little bit magical in nature. 

 

you also so should note that the storm tends to rip up the land. If the coast line closest to origin was not especially deep the sediment could be ripped up combined with the spiritual energy of the storm could create the crem. thus making the land rocky and preventing to much erosion.

 

very impressive by the way.

[Satsuoni]

Hmm... Well, the obvious question would be: what happens to the salt? AFAIK, the Roshar seas have saltwater, and Highstorms carry potable water (as long as you get the crem out). If it is fed from the sea, then the water should desalinate at some point.

As for undeground: we know that the water goes underground in Purelake just before Highstorm, so there is probably a lot of it underground, as you said (and probably part of it gets sucked out on the way by the Highstorm wave)

[Aether]

It should also be noted that we know from the Eshonai chapter of WoR that

the Shattered Plains is actually a huge city where the plateaus are buldings covered in a thick layer of Crem.

This would suggest that there is a net gain of mass to counteract the erosion, thanks to the Crem - at the very least this far east - though it might build really slowly since the area likely hasn't been inhabited for centuries, possibly millennia.

[The Rooster]

Speaking strictly in my capacity as a professional Chemical Engineer, trained in mass transfer phenomena and whatnot... I think it's magic.

[name_here]

Hmm... Well, the obvious question would be: what happens to the salt? AFAIK, the Roshar seas have saltwater, and Highstorms carry potable water (as long as you get the crem out). If it is fed from the sea, then the water should desalinate at some point.

As for undeground: we know that the water goes underground in Purelake just before Highstorm, so there is probably a lot of it underground, as you said (and probably part of it gets sucked out on the way by the Highstorm wave)

Salt stays behind when water evaporates. Actually, it's strange crem doesn't. Since it seems to be pretty stable as a solid once it comes back down, I doubt it's soluble in gasses, so it must be drawn up into the highstorms somehow or form from other materials inside the storm. It could be that there's a bunch of Ashmount-style volcanoes at the Origin, and the highstorms trap the ash and gasses and make crem.

There is apparently also more normal weather, mentioned when Dalinar attends the feast. But I expect that the highstorms tend to absorb or scatter local weather and happen often enough major normal storms are rare.

[Satsuoni]

Salt stays behind when water evaporates. Actually, it's strange crem doesn't. Since it seems to be pretty stable as a solid once it comes back down, I doubt it's soluble in gasses, so it must be drawn up into the highstorms somehow or form from other materials inside the storm. It could be that there's a bunch of Ashmount-style volcanoes at the Origin, and the highstorms trap the ash and gasses and make crem.

 

That was what I meant - if the water evaporates, then the crem - that precipitates out of storm water within days, IIRC, and forms a solid enough stone - should do the same. I guess that the volcanoes mixing in ash may have merit, but another thing to consider is the amount of the stuff - there is enough of crem to be in the water all over the continent - just how huge the volcano would have to be?

Actually, I've thought of a strange theory : we know that there exists water underground, and that water goes somewhere after the storm, and apparently not all of it goes into the rivers. So what if the underground layers of Roshar are somewhat sponge-like, possibly due to crem sediment? The storm never made sense to me as the weather pattern - it looked more like an explosion, aka detonation, which is (wiki):

 

Detonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it

IIRC, the storm structure is as follows:"low pressure" zone (water goes underground in Purelake), stormwall (moves in a single direction - outwards), sphere recharge zone(seemingly a lull), turbulent zone (wind and water going from any direction).

So what if the storm is like a detonation shockwave, but instead of the exothermic reaction, there is a zone where energy leaks from Spiritual realm, driving pressure front, that, in places, sucks the water out from the ground and drives it outwards? The water would be rich in minerals, being forcefully drawn from underground, and would create the observed zones (and would look like a wave in the sea, covering the fact that it is replenished from underground).

Well, I admit I don't know much about weather patterns, though, so I am probably wrong.

[Natans]

It should also be noted that we know from the Eshonai chapter of WoR that

the Shattered Plains is actually a huge city where the plateaus are buldings covered in a thick layer of Crem.

This would suggest that there is a net gain of mass to counteract the erosion, thanks to the Crem - at the very least this far east - though it might build really slowly since the area likely hasn't been inhabited for centuries, possibly millennia.

 

This was confirmed ?

[Satsuoni]

Well, there was indeed the city there, though rather than buried, it was part buried part eroded. It is in Eshonai readings.[

Edited November 27, 2013 by Windrunner
Spoilers...

[Gloom]

In regards to Roshar

Brandon Sanderson

It is a supercontinent. I won't say there is NOTHING out there, but (unlike Scadrial) there is not another full continent. Plate tectonics are not a factor on the supercontinent.

 

If I'm not mistaken, that would mean that most tectonic activity like earthquakes and volcanoes would not be naturally occurring.

 

I'm leaning towards a very porous crust that causes pressure to build from drainage on the Pangaea resulting in a semi weekly super geyser at the source.

[king of nowhere]

the salt argument is a good one. we already know that the highstorms are magical in nature, but I assumed it could be explained just by water getting sucked into the sky by the magic of the origin and then being nebulized so that it stays suspended long enough. but if that was the case, highstorm water would be as salty as seawater.

Another option then: we can considered established at thius point that roshar has a very large underground water system, big enough to drain the purelake during storms and to drain most of the water falling during highstorms. what if it is THAT undergorund system that feeds the origin of the storms? it would explain why the water is crem rich but not salty, and would keep a good mass balance. most of the substances carried away by water would be recycled in that underground system, turned into crem. it would not work in the long run, because some of the crem would still end up into the sea, where it cannot be recycled. so if vulcanism/plate tectonics are not a factor, I have to say either some shard is regularly digging up phosphorous from the bottom of the sea, or life on roshar is running on a clock and cannot last forever. it can still last for several millions years, however, which would make the point irrelevant to the story.

 

Of course, since the storms are magical in origin, it is fully possible that all the water and crem are "magicked in" and "magicked out", but I don't see a shard creating and destroying billions of tons of matter on a weekly basis just for the sake of it. I find more likely that it's moving stuff that is already around, hence I started calculating what kind of fluxes it would involve.

[Satsuoni]

Um, isn't that about the same as what I said?

And Gloom, it mean that the continent doesn't have volcanoes, nothing about sea floor, as to my understanding.

[Gloom]

I was clarifying. You did mention volcanoes.

 

 I guess that the volcanoes mixing in ash may have merit, but another thing to consider is the amount of the stuff - there is enough of crem to be in the water all over the continent - just how huge the volcano would have to be?

 

I also brought along a friendly quote.

[Satsuoni]

The first sentence was addressed to king of nowhere, gloom The origin of water, I mean, though I may not agree that all the water is available at the start of the storm- I think part of it gets replenished on the way.

And I just list possibilities: "have merit" means "I cannot discard a possibility", not that I agree with the idea...

[Shardbearer]

What if the crem exists as a very find dust in the air that basically stays afloat for a long time and only comes down when weighed down by the rain in the highstorms?

 

Then again, how would the dust get there in the first place? And how would it effect visibility? They don't seem to have trouble seeing the stars at night or anything like that.

 

So it's almost definitely something in the highstorms that isn't in the rest of the air.

 

What if there's a giant spren at the Origin that spews all that underground water into the atmosphere at an angle that makes it go from east to west in a big storm?

[Gloom]

Hmmm, another spren like Cusicesh the Protector, possibly even bigger, that blasts large volumes of water back into the atmosphere? A spren that may also create the whether conditions necessary for that water to remain airborne and create a highstorm?

 

Yeah, I could buy that.

[Swimmingly]

What if the crem is actually a chemical precipitate formed by a catalyst on the ground and several reactants in the air? Just throwing this out there, but it seems to be some kind of fertilizer (in that cremlings can take nutrients from it) and while the behaviour is more analogous to Earthly plants, please remember that this. Is. Roshar.

[Aether]

What if the crem is actually a chemical precipitate formed by a catalyst on the ground and several reactants in the air? Just throwing this out there, but it seems to be some kind of fertilizer (in that cremlings can take nutrients from it) and while the behaviour is more analogous to Earthly plants, please remember that this. Is. Roshar.

They do use crem as a fertilizer, at least on Lavis Polyp farms. Presumably, most plants use crem as a source of nutrients, not just cremlings.

 

EDIT: capitalisation run amok.

Edited December 13, 2013 by Aether

[dionysus]

Interesting observations.

 

My solution to the salt problem would be that the water does not drain towards the oceans like on earth, but towards the origin. Or at least the underground rivers. Now that theory has its own problem with water mass loss to highstorms over the oceans. My solution to this is that there is regular rainfall as well I believe. So water evaporating from the oceans and deposited as normal rainfall on the continent balances out the water loss of the highstorms as they pass over the oceans.

 

Also the process of getting crem into the highstorms simply cannot be explained using just our understanding of earthly weather. The evaporation to condensation cycle is purifying as other posters have pointed out.

 

But one thing I just realized is we are only looking at half of the equation of the highstorms. Where does all that air come from? I'd bet that at low altitudes we see the storms rushing away from the origin but at high altitudes we would see the air moving towards the origin to complete the mass balance.

Edited December 3, 2013 by dionysus

[Gloom]

I suppose that we should also consider the differences in gravity. It wouldn't be unreasonable to believe that in a world with lower than earth gravity like Roshar that sediment could be suspended in the atmosphere more easily than it could on earth. I would really hat to see the size of their hailstones.

[Aether]

Well, worst reported hailstorm on Earth was in Bangladesh on the 14th of april, 1986. The storm killed 92 people with hailstones weighing up to 1 kilogram (2 pounds)! <source>

 

Given those numbers, I'd rather make a Bridge-run then stand out in a Rosharan hailstorm.

[Swimmingly]

If everybody's under the bridge, then you would probably be the safest men in the army if you were doing both at once.