WIP (sort of tutorial to be) : Climates, applying Geoff's Cookbook at detail (some)

[Azélor]

I am starting to think that its too complicate to really be able to implement for me , to be precise I would need at least a month full time on that when perhaps a nice program could do it faster and implement all that tutorial in a click ...

I finished Pixie's tutorial for the whole CWBP2 and it took me a couple of hours. I still need to make some corrections. Still, it gives a good idea of what the weather is around the world.


Now I do have some comment/question about the tutorial itself.

1-It is not clear if the cold/hot currents use the absolute or relative temperature. Some cold current are hotter than ''lateral'' current therefore I applied the cold oceanic effect to some mild currents.

2- The currents at the poles are moving westward yes? As I understand it, there is a loop that starts at the equator flowing westward then poleward, eastward at the 45th latitudes, and then back to the equator. But I think there is another loop in the north starting at the 45th. It flows counter clock wise. Lastly, it is said that Antarctica has a counter current flowing eastward close to the coast but I can’t find a lot of informations on that.

3- Winds in the polar front move to the east. They are also known as the Westerlies. While I’m not sure how the winds behave at the Poles (high pressure area) I think the winds should converge to the Polar front.

4-Wetness map: As I understand it, all the wettest categories fall into the same category and need to be fused together. In total, there is only 5 level of rain left. It makes sense because the impact on the climate between 3000mm or 6000mm is not that large in comparison to the difference between 300mm and 600mm, for example.

5-The maritime influence maps are almost identical in January and July or I did something wrong? I think it's because the area affected is small.

6-Precipitation problem? I’m not sure how far the inland precipitations should go. I was just wondering if my dry zones are really supposed to be dry.

7- When you say ‘’ Halfway through the other category’’ it is based on the original layer or the modified one? I think that multiple effects should stack but each effect added has a weaker impact.


8-The temperature for high mountains seems way off, in my case. Mt Everest would be without snow acceding to the tutorial. I have a mountains range with similar characteristics as the Himalayas and the temperatures in summer go between 18 and 22... So we need colder mountains. I thinks the need to be able to have high mountains (over 6000 m) with temperature always below 0 Celsius at the tropics and maybe closer to the equator. As stated here: Snow line - Wikipedia, the free encyclopedia

My elevation map has 6 levels of altitudes (but the last one is marginal):

1: 0-500m
2: 500-1000m, these two are at the same temperature but:

3: 1000-2000m: lower the temperature like you did in the tutorial
4: 2000-4000 (high latitude): lower the temperature by one full category
5: 4000+ (very high): lower by 2 categories
And another one just for the highest summits: 6000 +: lower by another 2 categories

That way, even if there is a hot climate at the bottom, the summits of the high mountains will have snow all year long. Unless you are at the equator where 6000m is not always high enough to keep the snow.

[Iggy]

I have assembled Pixie's instructions into a single document and exported it as a PDF file for personal use. I could post it here but I would rather hear Pixie's approval of it first.

[Adversary]

This is an awesome tutorial! It reminds me of many things I have forgotten from my meteorology class (which oddly enough has nothing to do with meteors ). The main points I love have to do with the climates and ocean currents. There are a couple of assumptions that I can make about your planet from this tutorial. First you planet has an axial tilt of about 10-30 degrees. Less than that and you would not have noticeable seasons, more than that and the seasonal changes would be extreme. Second, your planet rotates counterclockwise as viewed from above (North). If it rotated the other direction the wind rotations would switch.

I didn't see your jet-streams. You should have one for each latitude zone, each moving from west to east. These will drive your temperature, weather and general climate. Look at North America. The important jet stream runs generally from Washington state to Maine. In the winter the jet stream dips into the central United States bringing cold air from Canada. This last year the jet stream looped further south than usual and Atlanta, Ga ended up with a major snow storm.

In your world the Jet stream will help explain your weather. If the jet stream runs north of your continent the predominant surface winds will come from the west will and the wet air from the ocean will make the north west coast more humid. The air will dry as it moves across the continent, especially in the shadow of mountains. As the jet stream moves south with winter, the wet zone will move south with it possibly causing monsoon rains. The east coast will not gain much benefit from eastern ocean winds in the winter and will mostly get drier air from the west. The southern half of the continent should have similar weather patterns with opposing seasons. Think about the jet streams remaining in place as the planet tilts under it. In winter (north continent) the jet streams all move south and north in the summer.

Another point is that weather will not cross the equator. More correctly, the weather will not cross the line where the sun is directly overhead. This area will obviously shift with the seasons; south in the winter, north in the summer. Where the sun is directly overhead the planet will have longer days, which heat the ground (and water) more so the air rises. North of the equator the air goes north and south of the equator it moves south. This rising air will act as a barrier to weather patterns. That is why hurricanes (or typhoons) never cross the equator. They tend to wander north, north of the equator and south to the south of it. Of course in the mountains the weather will be cooler (think of Equador) creating micro climates.

I hope I did not muddy the waters. This is a very complex subject and if it was perfectly understood the weatherman would always be right.

[ltan]

Iggy: If Pixie is ok with it, I would like to have a PDF version!

[vorropohaiah]

Iggy: If Pixie is ok with it, I would like to have a PDF version!

same here!

(and while were on the subject, does anyone know where to find the climate cookbook nowadays?)

[ltan]

vorrophaiah: I took a trip into the Internet Archives and dug up this link: 19th of June, 2013

If no one else does it, I will work on converting it to PDF if that is wanted.


Edit: DONE!

The formatting was coded nicely so all I had to do was save in PDF...

[Azélor]

I think I should add my own contribution here : http://worldbuilding.stackexchange.com/a/1395/147
There are some topics that we haven't really covered yet: Jet stream, El Niño, deep ocean circulation, fantasy climates ?

Maybe I should make my own thread ?

[su_liam]

Thank you, Itan! I've been looking around for that site. In desperation, I finally got permission from Geoff Eddy to post the worldbuilding and climate cookbook pages in my blog's goodies. The formatting was a little funky, but at least I could refer to the information and charts.

The Wayback Machine allowed me to pull up his other, mostly more linguistically-oriented stuff like the sound change applier which I hadn't kept on my hard drive. I am now slurping it up.
Did I remember to thank you

[Azélor]

Pixie, we're going (or just me) to make an automated process, possibly with photoshop actions. I don't know much about it yet but it can record all the step as I do them. So we can create an automated technique without having to code endless lines of gibberish. One thing I need to figure out is what exact actions should be done. It's mostly selecting layers, add/intersecting/exclude them with other layers and ''painting'' the results on a final or temporary layer.

I already have the workflow for the section on temperatures but now I'm at the part with the rainfall. As I already mentioned, figuring out what places are supposed to be dry require the combination of temperatures and precipitations.


There is 3 important steps to do:

1- find the temperature zones: Ice, tundra. A, B (hot or cold), C (Ca,Cb, Cc optional), D (Da, Db, Dc, Dd optional), so far, it's the easiest part because it's the least subjective
2- find the pluviometric regimes: winter dry, summer dry, or else it's always wet (f). That part is more complicated. I decided to change the regime coverage based on the fact that winter dry climate have very dry winters, much drir than summer are in summer dry climates. And winter dry usually have very wet summers. But all this suppose that the starting rainfall categories make sense.
3- find the humidity level, between humid, semi-arid and arid.

This is actually the most complicated part, because there are a lot of possibilities. I did try to estimate what areas should be dry based on the temperature and precipitation but I'm not sure it's good.

We can ignore the ice and tundra here, they are black.
Ignore the 2 colours of blue, they are both for the A. But light blue is Da
From the 25 possibilities, 13 from the top left are always wet and can be cleared. Or more specifically, they can be selected and put in a separate layer.
We see that, the hottest climate is in the top left of every section. it's the square that is the most likely to be dry with the same precipitation as the other colder climates. As precipitation get lower, all the section gradually becomes more arid until it's almost all desert except for the coldest areas.

Process example: select a humidity layer (humid), select a pluviometric regime (w), select a temperature zone (Ca)
the intersection of the 3 meta layers should give us the Cwa climate.


Here the image I'm using as a guide. Does it make sense?
simple climat couleur cmjn with color key copie.jpg

[groovey]

Hi again Guild! Azelor, if you managed to automate the process of figuring out climate you would have to be made the King of this place. I hope you do manage. I could be a tester once you have it, since mine is still pending an updated climate map and I've just recently started to mess up with my project again.

So best wishes for your work.