Top and Bottom of the Atmosphere

By Willis Eschenbach – R$e-Blogged From WUWT

Some days I learn a lot. Today was one of them. Let me start at the start. Back in 1987 in a paper entitled ‘The Role of Earth Radiation Budget Studies in Climate and General Circulation Research“, a prescient climate scientist yclept Veerabhadran Ramanathan pointed out that the poorly-named “greenhouse effect” can be measured as the amount of longwave energy radiated upwards at the surface minus the upwelling longwave radiation at the top of the atmosphere, viz:

The greenhouse effect. The estimates of the outgoing longwave radiation also lead to quantitative inferences about the atmospheric greenhouse effect. At a globally averaged temperature of 15°C the surface emits about 390 W m -2, while according to satellites, the long-wave radiation escaping to space is only 237 W m -2. Thus the absorption and emission of long-wave radiation by the intervening atmospheric gases and clouds cause a net reduction of about 150 W m -2 in the radiation emitted to space. This trapping effect of radiation, referred to as the greenhouse effect, plays a dominant role in governing the temperature of the planet. 

And here is what Ramanathan was talking about:

Figure 1. All-sky (both cloudy and clear) greenhouse effect. In climate science, “upwelling” means headed for space, “downwelling” means headed for the surface, “forcing” means a change in downwelling radiation, “LW” is thermal longwave radiation, and “SW” is solar shortwave radiation. 

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How Much Sun Could A Sunshine Shine?

By Willis Eschenbach – Re-Blogged From WUWT

It has been pointed out that while many of the global climate models (GCMs) are not all that good at forecasting future climate, they all do quite well at hindcasting the 20th-century global temperature anomaly [edited for clarity – w.]. Curious, that.

So I was interested in a paper from August of this year entitled The energy balance over land and oceans: An assessment based on direct observations and CMIP5 climate models. You’ll have to use SciHub using the DOI to get the full paper.

What they did in the paper is to compare some actual measurements of the energy balance, over both the land and the ocean, with the results of 43 climate models for the same locations. They used the models from the Fifth Climate Model Intercomparison Project (CMIP5).

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Solar Symmetry and Balance

By Willis Eschenbach – Re-Blogged From http://www.WattsUpWithThat.com

The CERES satellite dataset is a never-ending source of amazement and interest. I got to thinking about how much energy is actually stoking the immense climate engine. Of course, virtually all the energy comes from the sun. (There is a bit of geothermal, but it’s much less than a watt per square metre on average so we can ignore it for this type of analysis).

So let’s start from the start, at the top of the atmosphere. Here’s the downwelling top of atmosphere (TOA) solar energy for the northern and the southern hemisphere:

CERES NH and SH TOA solar radiation.png

Figure 1. Top of atmosphere (TOA) downwelling solar energy. This is averaged on a 24/7 basis over the entire surface of the earth.

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