The Köppen–Geiger climate classification made simpler (I hope so)

[Azélor]

I wanted to participate in the actual monthly challenge but ended up doing something else and life caught in the way. So I will post something else here. It is related by maybe I will repost in a new thread. I have been wanting to do this for some time. There are maps made to show the climates of the future but it's not really easy to understand what the changes are exactly, and where they occur. I did a couple of maps to try to better display the magnitude of the changes.

Summary: compare the climates from 2000 to 2100

First I took the data from here: http://koeppen-geiger.vu-wien.ac.at/shifts.htm
I modified the image and used the basic maps mostly.

Secondly, I chose the A1fi scenario because it seems to be the most plausible (but also a pretty pessimistic one).
This scenario predicts and increase of temperature of 4 degrees by the end of the century. Only the most optimistic ecologists believe we can still avoid passing over the 2 degrees mark, and that can only work if we adopt aggressive measures to curb down gas emission. But we are barely doing anything.

Thirdly I started this:

Only to find out that I did not really have sufficient data to make the 2100 map. I mean, I needed to know what area remained the same and which one would need to be changed.

I redid the maps in photoshop, maybe not the best way to do it but whatever


Right now, it's still just a bunch of weird colours.

This map shows the change of climate according to the categories of the Koppen classification following this table where each arrow represent a change of one category:

This is very useful for my project but probably not so much for most people. A map showing the change in Celsius would be more useful but that is not what I needed.
It also show where the tundra will disappear and where the glaciers will melt (although the process can take decades if not centuries).
The grey areas represent deserts, steppes and places where the aridity is changing. I cannot include it because everything that has to do with arid climates uses different temperatures thresholds compared to the other climates categories. Anyway the relevant data is better left for another map because there would be too many colours.


Here I looked at the changes in aridity. It only show the changes if it changes the category of the climate. So for instance, most of Southern Europe will become drier but not enough to become a steppe. Therefore the change is not displayed on this map because it is too small.
Also I need to remind that aridity is define as either an increase of temperature, reduction of precipitation or both at the same time resulting in an increased aridity.

I made it so there is one colour for the deserts and one colour for the steppes.
The outlook is bad overall.
Most of the red areas are tundra in the Andes turning into deserts which might not be that dramatic considering the area is already one of the driest on the planet. With this classification, tundra can be dry or humid, only the temperatures matter.

Rain pattern or seasonality:
I included the usual three patterns plus a moderately dry winter season for the Am climate.



Changes between the 2 periods:

The dark green means that precipitation tend to be more evenly spread out during the year and so they now lack a proper dry season. That doesn't mean an increase of precipitation, just that they are spread differently.
London will be able to grow palm trees with a climate similar to today's Marseilles.

Lastly, the evolution of ice shelves at their maximum and minimum using different sources.
Minimum:

Maximum:

The changes during the hot season is huge. Only the coldest bays around some parts of Antarctica will be cold enough to sustain the shelve in the south.
In the north, there is a small patch of ice survining just north of Greenland but the ice will be very thin, so I chose not to include it.
The ice cover is still significant in winter but is made of young ice (1-2 years old max) and is relatively thin.

[nwisth]

Impressive work, Azélor! It is very sobering to see a climate change scenario presented graphically like that, but what really made it easy to picture was your mention of the palm trees of the British Riviera.

In the A1fi scenario, would sea levels remain more or less the same?

-Niels

[Azélor]

They have started planting palm trees in Halifax. I would be depressed if they survived the winter.

About sea level, I've found that it could be between 0,3 to 1m.
It is an increase but not large enough to justify redrawing the coastlines.
At less than 1m I think the impact is mostly marginal as long as the winds are calm.
I assume most people living near the ocean did anticipate storms and built accordingly.
For them, a 1m increase is manageable but with a stormy weather the waves reach even higher.

By the horizon of 2200, the rise will be more dramatic as the melting of Greenland accelerate. 3-4m increase, maybe more.
4m and half of Florida is permanently flooded.

But on the short term, the biggest issue is not really the rising oceans.
It's human activities.
Urbanization, deforestation of the coastlines and subsidence https://en.wikipedia.org/wiki/Subsidence
Many cities like Miami are built right next to the sea on a spit https://en.wikipedia.org/wiki/Spit_(landform)
They have no mangrove to protect them from the winds/waves and concrete does not absorb water well well.

Subsidence is when the ground is sinking, usually because the people are pumping underground water.

[Charerg]

A bit off topic, but there actually are already palms growing in Cornwall, for example these ones at St. Mary's Church, Penzance (see Flora of Cornwall for more info):



I guess it's not common knowledge, but some palm trees are reasonably resistant to cold, as long as the temperature does not fall below zero for extended periods. Some areas where palms grow naturally receive snowfall every now and then, like the mountains of South Africa or Australia (the species in the above image grows in New Zealand, you could say that it's more of a palm tree of temperate climates rather than tropical ones).

[NadirtheFox]

I have to admit that I actually find your work quite usefull Azélor And kinda disturbing at the same time
Aaand I've finished july precipitation map: I also changed january a little bit: But when I tried to install the script I didn't get the option to use it. I double checked if I installed it correctly, I tried to install the other one... Still nothing. I looked for help in the internet and apparently it's because I'm using "elements version" and scripts are simply not available in it... But there is option to use them, I just can't click on it so maybe I'm just doing something wrong... Oh well.
After manual climate generation and quick cleaning: I got some weird holes in mountainous areas and in the far north where I didn't get any climates other than tundra and ice. I've managed to patch up the mountains (well... most of them) and I think that the far north should be mostly Dfc with some Dfd climate inland but I wanted to make sure in case I messed something up XD

[Azélor]

You could use the Gimp.

Most of the climates missing are Dc.
One of the mountains is a tundra, in blue.
Some in the est are Db close to the steppes, assuming they are humid because I did not check.

[Charerg]

Overall the climates look pretty good, though there are a few things that might be a touch off. I'd draw a few demonstrative maps if I had the time (maybe next weekend), but here's some quick feedback.

1. The first thing that pops up in the July precipitation map is that the northern hemisphere subtropical ridge (the high pressure zone between the Hadley and Ferrel cells) seems to completely disappear during july.

2. At first glance, the vast equatorial deserts you have in both of your equatorial landmasses seem a bit suspect. While I understand that those areas fall under rain shadow at least to some degree the deserts still seem a bit too extensive. Especially the western equatorial continent seemingly has the rain shadow on the wrong side of the coastal mountains (the coast west of the mountains should be dry, as with the Atacama and Namib deserts).

That's it for now, I'll try to post something more detailed during the weekend.

[Charerg]

Ok, so I started to think about the more detailed feedback (and how to represent any feedback in a semi-coherent and understandable fashion) and kind of ended up doing my own take on Twierdza (well, sort of, I'll try and stick with the basic stuff).

First off, the oceanic currents:


For the most part, they're similar to your original, though there are a few areas of deviancy:

1) The major one is probably in the inner ocean. I gave the counter-equatorial current a strong bias towards the northern hemisphere and also made it a "single hemisphere loop" like the Guinea current. I suppose this hasn't really been covered by the tutorial, but there is a possibility that the counter-equatorial loop only exists as a single loop (instead of the usual "double loop") if you have a case like the Atlantic Circulation:



In this case, I chose to pull this trick off because it felt the most natural solution to the issues with the positioning of the subtropical high below your eastern equatorial continent. The original current map has a cold current skipping equatorwards across open water, but this is an unlikely scenario: typically the waters would just be carried almost directly towards the east (or even slightly polewards) by the westerly winds, unless there exists a landmass to divert their course.

With the biased counter-equatorial current, the southern hemisphere "Mid-Ocean Loop" can be pushed further towards the equator, allowing for a coast-following cold current that would explain the existence of a subtropical high. That said, this is just one possibility. Alternatively this land arrangement simply might not generate a subtropical high in this area.

2) Secondly I have a warm current extending further east in the northwest corner of the map than was the case in the original. Seeing that there is a lot of open water there without any major obstacle, I think it's likely that there would be a current from the "Big Ocean" into the "Cold Sea", similar to the Gulf Current that reaches quite far into northern waters (as can be seen in the Atlantic Circulation map).


With that out of the way, I did a sort of combined pressure/potential rainfall map for January:



Basically it maps out the major high and low pressure belts. One thing worth mentioning is that the subtropical high pressure belt tends to be much more continuous during the cold season, and more broken during the warm season, as can be seen here (as well as by checking the sample maps of Earth). I haven't quite compared this yet to your January rainfall map, but at a quick glance there aren't a huge amount of differences. That said, there were a couple of areas that I noticed were unexpectedly dry, especially the "temperate region" in the northwest portion of the map. But more about that later, once I've actually compared the maps in detail.

[hunter714]

Hi guys,

I am amazed by the work behind this tutorial. You have my utmost admiration for doing this.

I decided to try to follow it. I must say before starting this, I didn’t have a clue about how climate works and what affects it and it took me some time to go through this (I need some time for things to settle in and well, it’s a complex subject too).

I have a bit rushed and didn't go too much in details for some things as I wasn't so sure about how to do them. I understood some things a bit later in the process and I think I’ll redo a pass on everything now that I got a clearer idea of how it works.

I stared with a randomly generated “planet” I could see as believable.

Then I started adding tectonic plates that would reflect what was already my continents and islands.
With it I tweaked a bit the continents, added some islands and mapped the elevation :



After this I followed the tutorial :

- Surface current :



- Air pressure and winds which I understand are not accurate enough for latter steps and my centers of pressure are way to big and it impeded me later :

January :


July :


- Zone of temperature

January :


July :


- Temperatures. I think most transition area are to straight and need to be redone appropriately to be more coherent :

January :


July :



- Precipitations. I ignored most of the Orographic lift effect as I am not really sure how to implement it without having all my mountains under great precipitation and how category 0 would interact with this :

January :


July :


And thanks to Charerg I generated a climate map with his gimp script :


I haven’t done the climates legend but if I understand correctly it’s the same colors used on the Köppen climate classification Wikipedia page.

Anyway thanks again to anyone who contributed on this. I had some fun doing this and it's quite interesting. I'll try to rework every step of the tuto to get a better result.

[Charerg]

The "category 0" rainfall has the wrong colour in the precipitation maps, which is likely the reason for the pink and white areas (those shouldn't appear).