The poles would be too cold and have much larger temperature swings with the seasons than actually occur. If we did the energy balance of each latitude independently, we wouldn’t get it right. Knowing global average temperature is not enough information to determine where it’s cold enough for snow and sea ice to form and where it’s not, and when. For Earth (and soon Mars) we do something a bit more complicated. You can change the albedo, or see what happens when you move the planet closer to or farther from the nearby star(s). Planets in Universe Sandbox ² have this simple global average energy balance to determine their temperature. Even a one or two degree change in global average temperature can involve major changes to the climate. We know that the greenhouse effect keeps the Earth a bit over 30 degrees warmer than what it would be without an atmosphere at all, which is a lot in terms of global average temperature. You can also specify the fraction of outgoing infrared energy that gets absorbed and re-emitted towards the surface by the atmosphere on the way out. In the simplest version it also depends on the albedo (or reflectivity): the amount of incoming energy from the star that is reflected back instead of absorbed. One can set up an energy balance equation and solve it for the surface temperature. The hotter an object the more it emits in the infrared. What is a planetary energy balance? The amount of energy coming in from the local sun is balanced by the outgoing energy emitted in the infrared. The energy balance of a planet determines the temperature at the surface. – Naomi, and the rest of the Universe Sandbox teamīalancing Energy to Calculate Temperature What follows is the working documentation for this feature, and should help answer some of the questions you may have. So we needed to respond to changes in the orbit, to incoming star-light, and even let you play around with some of the model parameters themselves.įinally we wanted to representatively illustrate the effect of Greenhouse gases in the atmosphere, including the changes in temperature that happen when we add more Greenhouse gases to the atmosphere due to human activities.
And we wanted something in the spirit of the sandbox, so that you can change other things about the simulation and see the interactions play out. We also needed something simple enough that we could do the calculations in real time. Where it’s cold enough for snow and sea ice, we paint the Earth white. In doing so we wanted something that would give us different temperatures at different latitudes, so we could show the seasons come and go. We’ve added a simple climate simulation to the Earth in Universe Sandbox.
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