Geo Realism: Discussion on a new SDK based map generator

[primem0ver]

Are you factoring in humidity to the equation to determine temperature. Or just looking for an independent equation not affected by humidity?

Yes. But not as accurately as I would like. I could not find an article/equation that used it. That may change with this new article I found.

Why does the bleed off matter at night? I mean are you going to have day and night? Cloud cover I thought would prevent bleed off more than anything else. Basically I would think wetter areas have less variation. It would be better to just go with humidity versus inland. I would think in and out solar radiation would be mostly effected by humidity.

I simply mean the cooling off that occurs at night. Regardless of humidity there is always a cooling that goes on when the sun is not up.

FYI this is the article I found. I haven't read everything yet but at first glance it may be the answer I was looking for:

A STUDY ON THE NORMAL ANNUAL VARIATION FIELD OF
LAND SURFACE TEMPERATURE IN CHINA

 

[johny smith]

I do not know a constant to factor in for the cool off at night. I mean the range for China or any one region I think would not be representative of the population because all are going to have more variation with less humidity right?

I thought this might help it gives the annual differences between January and July for the whole planet.

Spoiler :

Sorry I can not find anything for night and day differences.

 

[primem0ver]

I do not know a constant to factor in for the cool off at night. I mean the range for China or any one region I think would not be representative of the population because all are going to have more variation with less humidity right?

I thought this might help it gives the annual differences between January and July for the whole planet.

Spoiler :

Sorry I can not find anything for night and day differences.

I do appreciate the graphics. They may help me make sure the calculations are accurate if nothing else. And they will come in handy if I have to figure it out for myself.

As for the China vs the world; you are correct that humidity will effect temperatures to some degree. However, don't forget that there is a fairly wide range of humidity in the areas covered by the maps and area covered in the article. I can factor in humidity by guess work if necessary as long as I understand the correct order of magnitude to which it affects the temperature.

EDIT: Also notice this article is not on atmospheric temperature but land surface temperature (which is not affected by humidity except when clouds radiate back some of the light that heats). Since atmospheric temperature is based on both land temperature and atmospheric conditions, the base atmospheric temperature will be closely related. And that I believe is all I need for now. The humidity will affect the way the land heats the air, rather than how the sun heats the land (in general).

 

[AIAndy]

I do appreciate the graphics. They may help me make sure the calculations are accurate if nothing else. And they will come in handy if I have to figure it out for myself.

As for the China vs the world; you are correct that humidity will effect temperatures to some degree. However, don't forget that there is a fairly wide range of humidity in the areas covered by the maps and area covered in the article. I can factor in humidity by guess work if necessary as long as I understand the correct order of magnitude to which it affects the temperature.

EDIT: Also notice this article is not on atmospheric temperature but land surface temperature (which is not affected by humidity except when clouds radiate back some of the light that heats). Since atmospheric temperature is based on both land temperature and atmospheric conditions, the base atmospheric temperature will be closely related. And that I believe is all I need for now. The humidity will affect the way the land heats the air, rather than how the sun heats the land (in general).

The albedo of the ground has a very significant effect on the amount of energy from sunlight that is absorbed and therefore surface temperature. Ground covered by ice or snow reflects a lot of the incoming light so temperature stays lower.

 

[primem0ver]

The albedo of the ground has a very significant effect on the amount of energy from sunlight that is absorbed and therefore surface temperature. Ground covered by ice or snow reflects a lot of the incoming light so temperature stays lower.

You are correct sir. Which is why it is a significant part of the calculation even in its current form (notice the albedo box in the screenshot along with the four shortcut buttons for surfaces with specific significantly different albedos). The Chinese article above also takes albedo into consideration.

 

[AIAndy]

You are correct sir. Which is why it is a significant part of the calculation even in its current form (notice the albedo box in the screenshot along with the four shortcut buttons for surfaces with specific significantly different albedos). The Chinese article above also takes albedo into consideration.

Good, does your formula attempt to calculate the final temperatures or will there be a heat transport calculation between plots afterwards?

 

[primem0ver]

I am not going to worry about heat transfer between plots except in the ocean (from land to ocean). But that will be later.

 

[rightfuture]

maybe this could help a little. News story from today.

http://phys.org/news/2013-02-macroweather.html
"Lovejoy and his research team used a new kind of “fluctuation analysis” to show that there are three atmospheric regimes, each with different types of variability. Between the weather (periods less than 10 days) and the climate (periods longer than about 30 to 100 years), there is an intermediate “macroweather” regime. A graphic representation makes the case intuitively clear."

"While short-term weather is notoriously volatile, climate is thought to represent a kind of average weather pattern over a long period of time. This dichotomy provides the analytical framework for scientific thinking about atmospheric variability, including climate change."

it goes into more depth of course.

 

[primem0ver]

Thanks for trying rightfuture though the article isn't really technical enough to shed light on the current problems.

The Chinese method worked better than my original method, but it still has some serious issues. I am now looking at an article written in 1975 that did exactly what I am trying to do for January and July using a single, very complex equation and some parameters. And it worked for the entire earth. Hopefully I can update and adapt it to work with all 12 months.

 

[Thunderbrd]

lol... scientists will be turning to C2C to get an idea as to how to build their global models.

 

[ls612]

lol... scientists will be turning to C2C to get an idea as to how to build their global models.

There's a game called Civilization, where you get a climate simulation?

 

[Laskaris]

Pity I did not see the new posts earlier. primem0ver, I might have a solution for your problem:

A scientist named Baart Geerts has developed calculations to estimate the climate of a location empirically based on its geography. I believe that these calculations could be used to give the results you are looking for, in a fairly accurate way.

Obviously, Geerts' calculations are based on empirical data from Earth. So, if we are trying to calculate the climate for a planet with a very different continental layout from Earth (a pangaea, or an archipelago world consisting of nothing but small islands), the results will be somewhat off (but probably still useable). If, however, the planet has a similar continental layout to Earth (a few big continents and a few big oceans), the results should be quite accurate.

Sources:
Geography and climate (the very simple version, for students)
Empirical estimation of the annual range of monthly-mean temperatures (more advanced)

Here is how it goes:

From the latitude L (in degrees) of a location and the altitude h (in meters), you calculate the mean annual temperature Ta (in degrees celsius):

Ta = 27 - 0.0077 L² - 0.005 h

Secondly, with the latitude L (in degrees) and the distance d from the upwind coast (in kilometers), you calculate the annual range of temperatures Ra (in degrees kelvin):

Ra = 0.12 L d^0.2

According to Geerts, the mean absolute error when comparing the calculated estimates and the real measurements on a large sample of weather stations around the world is 2.2 degrees K for the mean annual temperature, and 2.6 degrees K for the annual range. Not too bad!

Now, from Ta and Ra, you can calculate the mean temperature of the warmest and coldest month, Twm and Tcm:

Twm = Ta + Ra / 2
Tcm = Ta - Ra / 2

From here, you can extrapolate the mean temperature of all the other months by using a bell curve.

For calculating Ra, the direction of the upwind coast depends on the general latitude and season:

Tropics (0° to 30°): east
Subtropics (30° to 40°): east in summer, west in winter
Temperate zone (40° to 60°): west
Subartic (60° to 70°): west in summer, east in winter
Artic (70° to 90°): east

If the prevailing winds vary by season (as in the subtropics or the subpolar zone), you calculate Ra two times using the equation above, once with d from the west coast and once with d from the east coast, and use the average of the two as your final Ra.

Prevailing winds can also change seasonally if there is a monsoon. We will have to enable the program to recognise particularly large continents (should not be too difficult), and simulate the monsoon over these large continents based on that.

This is the simplest set of such equations. You can refine them by factoring in distance from a north or south coast, an upwind mountain barrier, inland seas and so on and so forth. But let's start with the above, and see how it goes.

 

[primem0ver]

Pity I did not see the new posts earlier. primem0ver, I might have a solution for your problem:

A scientist named Baart Geerts has developed calculations to estimate the climate of a location empirically based on its geography. I believe that these calculations could be used to give the results you are looking for, in a fairly accurate way.

Obviously, Geerts' calculations are based on empirical data from Earth. So, if we are trying to calculate the climate for a planet with a very different continental layout from Earth (a pangaea, or an archipelago world consisting of nothing but small islands), the results will be somewhat off (but probably still useable). If, however, the planet has a similar continental layout to Earth (a few big continents and a few big oceans), the results should be quite accurate.

Sources:
Geography and climate (the very simple version, for students)
Empirical estimation of the annual range of monthly-mean temperatures (more advanced)

Here is how it goes:

From the latitude L (in degrees) of a location and the altitude h (in meters), you calculate the mean annual temperature Ta (in degrees celsius):

Ta = 27 - 0.0077 L² - 0.005 h

Secondly, with the latitude L (in degrees) and the distance d from the upwind coast (in kilometers), you calculate the annual range of temperatures Ra (in degrees kelvin):

Ra = 0.12 L d^0.2

According to Geerts, the mean absolute error when comparing the calculated estimates and the real measurements on a large sample of weather stations around the world is 2.2 degrees K for the mean annual temperature, and 2.6 degrees K for the annual range. Not too bad!

Now, from Ta and Ra, you can calculate the mean temperature of the warmest and coldest month, Twm and Tcm:

Twm = Ta + Ra / 2
Tcm = Ta - Ra / 2

From here, you can extrapolate the mean temperature of all the other months by using a bell curve.

For calculating Ra, the direction of the upwind coast depends on the general latitude and season:

Tropics (0° to 30°): east
Subtropics (30° to 40°): east in summer, west in winter
Temperate zone (40° to 60°): west
Subartic (60° to 70°): west in summer, east in winter
Artic (70° to 90°): east

If the prevailing winds vary by season (as in the subtropics or the subpolar zone), you calculate Ra two times using the equation above, once with d from the west coast and once with d from the east coast, and use the average of the two as your final Ra.

Prevailing winds can also change seasonally if there is a monsoon. We will have to enable the program to recognise particularly large continents (should not be too difficult), and simulate the monsoon over these large continents based on that.

This is the simplest set of such equations. You can refine them by factoring in distance from a north or south coast, an upwind mountain barrier, inland seas and so on and so forth. But let's start with the above, and see how it goes.

Thanks. This may help. However, keep in mind that this calculation does have to be 100% correct in terms of the effects of geography. The climate simulation will take care of differences resulting from geography provided I have a starting point (which is what I am looking for here). I need to know the approximate temperature of the region that exists prior to the affect of weather systems and I need to approximate the starting temperature of the air masses themselves before they start moving across the continents.

I also wrote a professor at Clark College (in Washington state) who has some scripted software posted that models radiative convective systems for his students and he has been very helpful. Hopefully between the two of these sources I can come up with an effective solution.

 

[ls612]

Thanks. This may help. However, keep in mind that this calculation does have to be 100% correct in terms of the effects of geography. The climate simulation will take care of differences resulting from geography provided I have a starting point (which is what I am looking for here). I need to know the approximate temperature of the region that exists prior to the affect of weather systems and I need to approximate the starting temperature of the air masses themselves before they start moving across the continents.

I also wrote a professor at Clark College (in Washington state) who has some scripted software posted that models radiative convective systems for his students and he has been very helpful. Hopefully between the two of these sources I can come up with an effective solution.

Are you still expecting this to be ready to merge by the end of the month or so? Because we are planning on releasing V29 around the 20-25th of the month (whenever all known bugs get fixed and I find time to do the upload) in anticipation of this being added first thing or so after release.

 

[primem0ver]

Are you still expecting this to be ready to merge by the end of the month or so? Because we are planning on releasing V29 around the 20-25th of the month (whenever all known bugs get fixed and I find time to do the upload) in anticipation of this being added first thing or so after release.

No. I wasn't planning on that in the beginning. I believe I said v30. That may not even be possible with this delay. We will see.

 

[ls612]

No. I wasn't planning on that in the beginning. I believe I said v30. That may not even be possible with this delay. We will see.

Yes, that would be the v30 development cycle which starts later this month. But go ahead and take your time, it is good to have a polished product at the end of all this. And I'm really looking forward to this!

 

[Raven Destroyer]

i rather have a good product at V40 then a product hung together using Ductape at V30 while i hope it will be a good product for V30 i also know that 90% of C2C work is fronteer work defining and Redefining what is and isn't possible you guys are really amazing

 

[Hydromancerx]

So how is the progress on the Georealism stuff now that its pre-v30?

 

[ls612]

So how is the progress on the Georealism stuff now that its pre-v30?

Prime PMed myself and others about math troubles he was having with the temperature simulation. I haven't heard back from him on that since then, so he may or may not have sorted that out.

 

[strategyonly]

Prime PMed myself and others about math troubles he was having with the temperature simulation. I haven't heard back from him on that since then, so he may or may not have sorted that out.

Did anyone know any Math/Calculus that can HELP him then?? Laskaris ??

ANYONE