# Introductory Climate Modeling

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Introductory Climate Modeling
Presented by Dr. Robert MacKay Clark College physics and meteorology

Earth in space See the first 4 videos at:
These are a very nice introduction to radiation from Earth and Sun.

Earth in space The rate of Solar energy absorption by Earth is
pR2*(1-a)So where R is Earth’s radius a is the mean planetary albedo So is the solar constant ~1365 W/m2 The mean emission rate for terrestrial (longwave) radiation is 4pR2*sT where s=5.67x10-8 W/m2/K4 T is Earth’s mean annual temperature

Earth in space or Setting absorption equal to emission gives
pR2*(1-a)So =4pR2*sT4 or This is about 33 K lower than Earth’s mean surface temperature of 288 K

A “flat” earth with an atmosphere that absorbs no solar radiation but absorbs all long-wave radiation coming from Earth’s surface. Both the earth’s surface and the atmosphere are assumed to be black bodies for longwave radiation. The atmosphere emits radiant energy equally towards and awy from Earth’s surface.

S This is about 15 K higher than Earth’s mean surface temperature of 288 K A “flat” earth with an atmosphere that absorbs no solar radiation but absorbs all long-wave radiation coming from Earth’s surface. Both the earth’s surface and the atmosphere are assumed to be black bodies for longwave radiation. The atmosphere emits radiant energy equally towards and awy from Earth’s surface.

From K. Trenberth, J. Fasullo, and J
From K. Trenberth, J. Fasullo, and J. Kiehl, EARTH’S GLOBAL ENERGY BUDGET BAMS 2009

S Atmosphere absorbs a fraction, g ,of the total solar radiation absorbed by the planet Atmosphere absorbs a fraction, e of all long-wave radiation coming from Earth’s surface. Through Kirchoff’s radiation law the emissivity of the atmosphere for long-wave radiation equals its absorptivity. Earth’s surface is assumed to be a black bodies for long-wave radiation. The atmosphere emits radiant energy equally towards and away from Earth’s surface.

Estimating g=0.29 and e=0.9 from Khiel and Trenberth Energy Balance diagram
A “flat” earth with an atmosphere that absorbs no solar radiation but absorbs all long-wave radiation coming from Earth’s surface. Both the earth’s surface and the atmosphere are assumed to be black bodies for longwave radiation. The atmosphere emits radiant energy equally towards and awy from Earth’s surface.

This is about 3.5 K lower than Earth’s mean surface temperature of 288 K
Estimating g=0.29 and e=0.9 from Khiel and Trenberth Energy Balance diagram A “flat” earth with an atmosphere that absorbs no solar radiation but absorbs all long-wave radiation coming from Earth’s surface. Both the earth’s surface and the atmosphere are assumed to be black bodies for longwave radiation. The atmosphere emits radiant energy equally towards and awy from Earth’s surface.

Thermal Inertia Of Oceans
I Net radiation intensity (W/m2) A Area of surface d depth of ocean mixed layer C specific heat capacity of oceans r the density of water If d=100 m MacKay and Ko 1997

Stella version:

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Diagram from VUE. Visual Understanding environment

Conclusions Simple conceptual climate models can help students learn about climate modeling and the climate system. Climate models of all sort provide Interactive engagement opportunities for students. Causal loop diagrams offer an excellent visual communication tool for both student and instructor.

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