CAPE Calcs and Storm Feats (Staff only)

[Mr. Bambu]

This was lightly brought up in this thread, but not enough, I feel.

Basically, our storm calcs function under a standard of 1.003 kg for density of a cloud. Some time ago (before I was a staff member here), I looked into that and found that it wasn't the density of a cloud but the density of air at high altitudes.

This means we have a decision before us. If it has been discussed previously, feel free to dismiss me. But here is the decision.

Can we conclusively say that cloud calcs will affect the air around it, too? Does CAPE cover the air's mass as well, or should we only include air density in KE calcs, or not at all?

Here is a graph uploaded in the source thread regarding air density at high altitudes.

Here are multiple sources stating 0.0005 kg/m^3 is the true density of a cloud.

Now, this is for cumulus clouds. Storm clouds would likely be considerably more dense. But should we just default to density of the air? Is there a reason for that?

As of right now, I'm not looking to create any vast wiki-wide changes. I just do math sometimes, preferably using more intelligent people's methods. But these questions have been on my mind for awhile. And the only answer I've gotten is to ask others, or "lol but if we change then we'd have to redo the whole wiki so what then hmmm lol".

TL;DR why do we use 1.003 kg/m^3 as cloud density for storm calcs, and if no answer can be found, then should we revise this?

 

[Antvasima]

Thank you for making this thread.

I would appreciate if somebody could ask all of the current calc group members, along with DontTalkDT and Kaltias, to participate here.

 

[RKGenki]

Quoting Executor N0 from a thread that was made some hours ago

The calc about the 1.003 kg/m┬│:

 

[Mr. Bambu]

That is a suitable answer, I suppose, as to where we got the density from. So this is the density of the air inside of the cloud as well as the cloud itself. And that's what we use.

That makes sense. And we're sure CAPE applies to this air as well, yes? KE I don't doubt if we're accounting for literally moving atmosphere from Point A to Point B, but is CAPE accounting for the density of only the vapor itself or the air that is within the vapor, too?

 

[RKGenki]

I asked Executor for his input

 

[DontTalkDT]

1.003 kg/m^3 is good to use for KE calcs IMO.

For condensations and stuff the approiate Liquid Water Content for the cloud should be used instead.

Not sure how it is with CAPE, I have not really read much about it. I think CAPE only bothers air movement, so you probably want gas density.

 

[Antoniofer]

I think it depends if CAPE use mas of air or mass of water with its constant, someone should take a look.

 

[Therefir]

We had a long discussion about this on Assaltwaffle's wall.

 

[Mr. Bambu]

So it looks like CAPE was never decided, but it was generally agreed that KE would typically mean manipulating the air around it.

 

[Antoniofer]

However, I think there's a few of calcs that use air density when they generate clouds, and as DT said, better use liquid water content.

 

[Mr. Bambu]

Generating clouds, absolutely. But KE storm feats can probably remain the same.

But yeah if you're just bringing a cloud into existence, you should only account for the water itself.

 

[Antoniofer]

Really is that, at least in real life, storms do not "move" from a place to another, it just generate cells and create an illusion of movement. Several feats use the same logic, but apparently is more easy to believe that it moved a storm in another place with tk. KE s still valid if it moved via shear strength tho.

 

[Mr. Bambu]

That's true. But rarely does fiction consider how a storm would function in real life.

 

[Antoniofer]

They generally imitate reality, at least for "detailed" verses. One can see exactly what happens in real life happening fiction (refering to forming clouds), and yet it will assume the clouds moved from over the horizont to that point. I remember a vidoe showing clouds forming quickly in a clear sky, but I lost it and there's hundreds of videos like that in youtube.

 

[Andytrenom]

Really is that, at least in real life, storms do not "move" from a place to another, it just generate cells and create an illusion of movement. Several feats use the same logic, but apparently is more easy to believe that it moved a storm in another place with tk. KE s still valid if it moved via shear strength tho.

I guess that shouldn't be the default assumption then. Makes sense to me .

 

[Mr. Bambu]

Things like the infamous Dark Souls storm calc for Nameless King? That is a cloud clearly moving. Verses can sometimes imitate reality, absolutely. But in-verse logic trumps reality's laws. If magic makes a storm form above you, pulling it in from the outlying atmosphere, I think a normal KE calc would apply.

Of course, generally, this decision is a downgrade of one or two tiers for most storm feats.

But yes. If a storm is forcibly moved by some act of strength of the character, I think it should operate under the assumption that the rest of the air is moved, too. If the cloud just forms, or something, absolutely, we should only consider 0.5 g/m^3.

 

[Andytrenom]

I think it depends on the nature of the character's abilities and what makes the most sense with that in mind.

@Mr. Bambu If the cloud is explicitly depicted as being moved then KE should absolutely apply, but if what Antonio said is true, then it shouldn't be the default assumption for every storm feat.

 

[Antoniofer]

I don't say is not possible for the clouds moving, but it should be the standard that the storm formed above. Let's be honest, if a storm appeared from nothing people will just assume it moved from a point beyond horizont rather than it just formed in the air, even tho the lastest one happens in real life (just way quicker) and is more factible. It should be more easy to tell when the game/animation/movie have good quality.

 

[DontTalkDT]

If one doesn't know whether it is created or moved one should really calculate both and take the low end unless there is a good reason against that.

 

[Mr. Bambu]

That much I can agree to, yes.

 

[Antoniofer]

Ok, then, perhaps do we need to update the Storm Calculation page?

Also, what about CAPE? do we still use mass of air to calculate it?

 

[Antvasima]

Should I unlock the Standard Storm calculations page, or do you further need to discuss how to modify it first?

 

[DarkDragonMedeus]

I'm unsure about CAPE calcs, but the 1.003 kg/m^3 should certainly remain for Kinetic energy related cloud feats. For example, Lina mentioned that Wario's Low 5-B is perfectly legit. I think DonTalk makes sense here.

 

[Therefir]

So if I'm not mistaken, the real problem is that some storm calculations assume that clouds are moving without any proof, rather than forming like in real life.

 

[Andytrenom]

Can someone clarify whether this feat should use cloud+air density or just cloud density?

Here's the context

Choze fires an energy blast at Suiryu, which Suiryu intercepts and kicks into the sky. Resulting in clouds above basically being tunneled through.

 

[Antoniofer]

@Andy, for KE we still deside to use the 1.003 kg/m^3, it also seems the character used shear strength to disperse the clouds rather than a power to vaporizise them; basically if you move cloids indirectly (ala Almight) we still use KE normally.

 

[Mr. Bambu]

Quoting directly the Wikipedia article.

"CAPE is effectively the positive buoyancy of an air parcel and is an indicator of atmospheric instability, which makes it very valuable in predicting severe weather."

It goes on to talk of other things. However, from what I can tell, it is largely referring to both the air and the vapor itself.

"Even if the air is cooler on the surface, there is still warmer air in the mid-levels, that can rise into the upper-levels. However, if there is not enough water vapor present, there is no ability for condensation, thus storms, clouds, and rain will not form."

Basically, CAPE is just less dense air rising and generating potential energy, making it more likely to gather vapor and cause storms, hence its use in predicting the likelihood in storms and our usage of it for the energy of a storm. Makes sense, yeah? But the vapor itself isn't needed, CAPE can still happen, it just won't generate a rainstorm.

So, to conclude:

• KE should absolutely use the 1.003 kg/m^3 for its calculations as long as one can prove the cloud was moved (dispersion will also do) by the character's power. It has to be proven to form in an unnatural manner, basically.

• CAPE should use 1.003 kg/m^3 and should not experience changes.

• Cloud vaporization, for example, would revert to 0.00005 kg/m^3 rather than 1.003 kg/m^3, as that is the real density of the cloud itself, and what is being vaporized.

Am I missing anything?

 

[Antoniofer]

For calculating formation of clouds it also use the density of 0.5 g/m^3, I think the method is enthalpy of formation but I'm not sure

 

[Mr. Bambu]

Formation of clouds, sure, but storms should still use CAPE, no?

 

[Antoniofer]

If the scientist of the world agreed themself, the results should be similar (at least with rain), but yeah, storms should use CAPE.

 

[BlackeJan]

Sorry but I wanna ask if this was to be applied then what would all the storm Calcs become then? Like would they become 7-B or so?

 

[Antoniofer]

Don't think if we have the time to look into all the storm calcs and recalc them, at least not now. But any calc that use real time footage or it imitate it should use CAPE or creation.

 

[Antvasima]

What do you think DontTalk?

 

[Mr. Bambu]

Even feats that might need reworked (shouldn't be many) would probably become downgraded by a tier or two. Nothing major.

 

[DontTalkDT]

Still trying to get my head around c.a.p.e. Maybe you guys can help me with that.

1. We use that if a storm happens, yes? In other words if someone creates clouds and a lot of wind we use c.a.p.e and if there is no wind we use condensation?

2. On the standard storm page the "height" is given as 13,000m. Were is that coming from?

3. The c.a.p.e is calculated by integrating from the level of free convection (LFC) to the height of the equilibrium level (EL). Looking at this source I found in the thread linked on the standard storm calculations page the upper border of the storm is around the EL, but the bottom border of the cloud is around the LCL, not LFC. Is LCL > LFC?

4. Does the entire cloud mass go through the potential difference given by the instability?

Edit: We should probably also write a page regarding calculating cloud movement and cloud creation via condensation, so that we we can note cloud heights for different cloud types and which density to use when.

 

[Antoniofer]

I was looking for info about CAPE too but the really is that i do not understand...

1) I guess if there's no sign of movement or winds we can go for creation, although we can still use CAPE (Assuming that our standards do not change about it). Although, in real life when storms forms they seems to move when the reality is that is just forming cells; so even if they seems to move, they can still be forming.

2) Is that height of cumulonimbus clouds? If it is, then we have used lower values, bambu told me that is at least 30000 ft, although most of our calcs use 12 km

3 -4) No idea...

 

[DontTalkDT]

2) Is that height of cumulonimbus clouds? If it is, then we have used lower values, bambu told me that is at least 30000 ft, although most of our calcs use 12 km

According to wikipedia the typical height a cumulonimbus cloud reaches is 12000m, while the base of the cloud is formed at 200m to 4000m alitude. That would suggest a cloud height, from base to top, of 8000m low end and 11800m high end.

 

[Mr. Bambu]

Still trying to get my head around c.a.p.e. Maybe you guys can help me with that.
1. We use that if a storm happens, yes? In other words if someone creates clouds and a lot of wind we use c.a.p.e and if there is no wind we use condensation?

2. On the standard storm page the "height" is given as 13,000m. Were is that coming from?

3. The c.a.p.e is calculated by integrating from the level of free convection (LFC) to the height of the equilibrium level (EL). Looking at this source I found in the thread linked on the standard storm calculations page the upper border of the storm is around the EL, but the bottom border of the cloud is around the LCL, not LFC. Is LCL > LFC?

4. Does the entire cloud mass go through the potential difference given by the instability?

Edit: We should probably also write a page regarding calculating cloud movement and cloud creation via condensation, so that we we can note cloud heights for different cloud types and which density to use when.

1. CAPE is standard for storms, yes. It is standard if KE cannot be applied.

2. No idea. I recall 30000 feet being standard based on an image of storm clouds forming, which translates to 9144 meters. That's what I tend to use.

3. No idea, much like Anton.

4. Yes, the entire mass is considered.

 

[Antvasima]

You can invite Executor to take part in this discussion as well. Maybe he is able to help?

It is too bad that Assaltwaffle and Kepekley23 are not available.

 

[DarkDragonMedeus]

CAPE is to storm feats what Potential energy is to launching feats basically. Also, I have messaged Executor.