[ExI] Diminishing influence of increasing carbon dioxide on temperature
anders at aleph.se
Fri Aug 15 00:16:40 UTC 2014
Tomaz Kristan <protokol2020 at gmail.com> , 14/8/2014 2:29 PM:
My take on this.
Measured wind speed profiles look like they have maxima around 60 km height, with 100 m/s velocities. http://ase.tufts.edu/cosmos/view_picture.asp?id=1103Earth has a maximum around 10 km, with a maximum of a few tens of m/s.
Venus scale height is 15.9 km, Earth's average 7.64 km. So the Venusian wind maximum is 3.77 scale heights up, while on Earth it is 1.3. At first that seems to suggest that there could not be much transfer since the atmosphere would be pretty attenuated. But remember the 92.1 bar pressure at the surface! exp(-3.77)*92.1=2.1 bar: at this altitude the atmosphere has twice Earth pressure, and it is significantly denser. So the total heat transfer capacity is several times, perhaps an order of magnitude, larger.
The advection timescale (vind velocity / radius) of Earth and Venus are both of the same size, far shorter than the radiative timescales and hence producing a circulation-dominated temperature distribution: http://www.mi.uni-hamburg.de/uploads/media/6._Planeto_dynamics.pdf
Anders Sandberg, Future of Humanity Institute Philosophy Faculty of Oxford University
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