Depth and temperature

[ZeekDaGeek 0]

Does depth not effect temperature in TerraFirmaCraft?

 

I just finished digging down to Y = 10 expecting that the further I went down the colder it would get, expecting that I could use this fact to preserve food, however, it doesn't seem to be the case.I expected after getting low enough down that there would be a concept of permafrost (http://en.wikipedia.org/wiki/Permafrost) where at some point it would drop below freezing regardless of what time of year it was, this never happened, even though I'm extremely far north in my world (Z = -12,000)...

[Bioxx 796]

if anything, the temperature would actually increase with depth as it does in RL. This however is not currently present in TFC.

[Visitor 36]

if anything, the temperature would actually increase with depth as it does in RL. This however is not currently present in TFC.

I believe it depends on the depth in question and the climate in the area. In warm climate/during summer, you'd have to get deep for temperature to start going up. Due to insulation the earth provides, for quite a few feet of depth the place would actually be getting colder in relation with the outside. Underground temperature is simply more stable thorough the year than the outside, usually.

[InsaneJ 561]

As you said, the temperature underground is more stable. The average temperature is also higher than above ground. During warm days we experience underground as being cool. During the winter (and cold nights) we experience underground as being warm. Because of this people have long stored things underground. Not because it's actually cold, but because the temperature is more stable and thus easier to manage. Here's an graph to show the effect:

 

During summer it's colder than outside, during winter is warmer than outside. The reason for this is that the ground is being kept warm by the earth's core. That giant spinning ball of liquid iron in the center is what's keeping us warm. Here's a nice graph showing depth and temperatures.

If you want cold, go up. If you want warm, go down.

[Terex 108]

If a block is 1 metre tall, we can only dig down some 100 metres. For such shallow depths, temperature is actually quite steady so TFC is inadvertently already correct. 

 

EDIT: Technically we could allow for a 3C increase in temperature over a 100 block depth range. Still very small gradient.

[Euphoric 48]

Not really. What keeps underground temperature stable is insulation from the outside. You don't feel effects of earth's internal heat unless you are really deep, like 1 km.

 

Terex: that is right, but this is game, not reality simulator. If that was the case, there wouldn't be any pockets of lava underground. So from gaming mechanics, there could be 50°C at the bedrock irrelevant to how it is on the surface.

[TomatoThief 53]

Wikipedia suggests the geothermal gradient to be roughly 1º C per 40 meters. That's a non-trivial change for modern mining subterranean operations, but not so for TFC. If your normal surface is around 120m in TFC, going to bedrock would be a 3º C change. That's about a 6º drop in F. Probably not enough to warrant extra coding in TFC. I might support a stable underground temperature, but I don't know how it could be coded so as not to be abused, especially when body temperature becomes a core mechanic.

 

http://en.wikipedia.org/wiki/Geothermal_gradient

[Terex 108]

/ That's what i said.

 

Ok for arguments sake, we can have any temperature gradient we like because this is a game. But there is no real purpose to have it in the game, so i say leave it

[Hygiliak 11]

Let  TMP = ambient temperature as it is being calculated now (in Celsius)

and DEG = ambient temperature proposed by me (in Celsius)

 

I propose this formula:

 

If (Stability>0)

  DEG = TMP

Else If (y<=128)

  DEG = 12

Else If (y<=144)

  DEG = ((144-y)*12+(y-128)*TMP)/(144-128)

Else

  DEG = TMP

 

Basically I propose adding a stable zone with 12 Celsius and another gradient above it, while keeping the current model in seismically active areas.

[InsaneJ 561]

Not really. What keeps underground temperature stable is insulation from the outside. You don't feel effects of earth's internal heat unless you are really deep, like 1 km.

 

Terex: that is right, but this is game, not reality simulator. If that was the case, there wouldn't be any pockets of lava underground. So from gaming mechanics, there could be 50°C at the bedrock irrelevant to how it is on the surface.

Sorry, but that is nonsense. It's the same as saying that a tea mitten will never get warm on the outside because it's insulating the hot tea cattle inside. Of course it will get warm on the outside, and of course the earth's crust will be warm on the surface due to the heat being generated at the earth's core.

 

I agree that the 256 height of Minecraft shouldn't be treated a simulation. Having additional thirst added due to heat at lower levels might make mining more difficult though. Then again, it might make for some interesting game mechanics. Having a bloomery/forge at Y 10 to be able to produce even stronger materials for example.

[scotty2 11]

Sorry, but that is nonsense. It's the same as saying that a tea mitten will never get warm on the outside because it's insulating the hot tea cattle inside. Of course it will get warm on the outside, and of course the earth's crust will be warm on the surface due to the heat being generated at the earth's core.

 

I agree that the 256 height of Minecraft shouldn't be treated a simulation. Having additional thirst added due to heat at lower levels might make mining more difficult though. Then again, it might make for some interesting game mechanics. Having a bloomery/forge at Y 10 to be able to produce even stronger materials for example.

 

Part of it is nonsense- but the stability of underground temp is indeed due to underground insulation from outside air and lack of effective convection.

The geothermal gradient is far too small to account for difference in surface temperature vs. a cave that is 80 feet deep.

 

In many places, even underground temps are dictated more by heat exchange rate between the surface and the atmosphere. This is how we have permafrost. There is no less geothermal energy available in tundra and the poles.

[Kittychanley 1,002]

Just something to keep in mind, the decrease of temperature due to increasing altitude has already been scaled to account for the limited world height. So even though most people take the 1 block = 1 meter literally, TFC actually scales from sea-level up to y-584 (so about 450 blocks) to be the equivalent of actual sea-level all the way up to the lower-upper troposphere, or about 11,000 meters.

 

The official commit message reads as follows:

 

Also updated height-based temperature. IRL, temperature declines linearly with altitude from sea level, but to replicate this in TFC causes weirdness due to the scale. instead, temperature decreases exponentially from sea level to 255, reaching the same decrease as it would have had it acted linearly. Temperature decreases linearly after this, until y = 584, which represents the lower-upper troposphere. above 11 km irl, temperature remains constant for the most part.

 

So technically speaking, it would be perfectly acceptable if this altered scale was applied to temperature changes underground as well.

[scotty2 11]

Just something to keep in mind, the decrease of temperature due to increasing altitude has already been scaled to account for the limited world height. So even though most people take the 1 block = 1 meter literally, TFC actually scales from sea-level up to y-584 (so about 450 blocks) to be the equivalent of actual sea-level all the way up to the lower-upper troposphere, or about 11,000 meters.

 

The official commit message reads as follows:

 

 

So technically speaking, it would be perfectly acceptable if this altered scale was applied to temperature changes underground as well.

 

Agreed, completely.

 

Was just pointing out that cave air temperature IRL (until geothermal gradient becomes a stronger forcing factor than atmospheric- see: deep) follows average above-surface air temperature for a reason. It's merely a fantastic heat sink for external temperature forcing upon the planet. Hard to move in either direction. It's not because the earth keeps the temp up, so what Euphoric said was in fact true.