Wednesday, September 5, 2012
It is Not Rocket Science
For the mixing layer I have used 17C as a rough average which would effectively radiate at 401Wm-2. Since that layer is between 30 and 150 meters deep, there is not a lot of radiating going on, but the effect radiant energy is convenient.
The "upper thermohaline" is using some liberties. There is though a stratification layer between 700 and 1000 meters that tends towards this average temperature, 10C with an effect energy of 364Wm-2.
The 4C abysmal thermohaline is a little more conventional. The 334Wm-2 effective radiant energy of 4C has that remarkable coincidence or appearing to be related to the 334 Joules per gram heat of fusion of water and the maximum density temperature of fresh water.
The little model has a red "Thermal Equator" to remind everyone that the sphere we live on is not uniformly spherical in a heat capacity sense, more egg shaped. The atmosphere though is more symmetrically related to a pure sphere in an energy transfer sense. With most of the thermal mass, solar insolation and stronger atmospheric circulations in the southern portion of the global, it should make a better frame of reference for analyzing heat flows.
At the higher thermal mass end of the pool is a brown block representing land. Above that a gray block representing ice. On the other end of the pool is another gray block that extends down to the 4C layer. The range of 306 to 316 Wm-2 represents the range from salt water freezing to fresh water thawing/freezing. The same could be applied to the deep end of the pool, but the shallow end would be more greatly impacted by that range.
The difference between the 425 skin layer and the 401 mixing layer 24Wm-2, represents a range of uncertainty. Under calm surface conditions, the effective radiant energy would be closer to the 425 and under high surface wind conditions closer to the 401Wm-2.
The difference between the 364Wm-2 and 334Wm-2 deeper layers is 30Wm-2 and the difference at the gray ice block is 10Wm-2. That would mean the gray ice block is likely to be less variable that any of the other thermal boundary layers. Another fine reason to select the ice boundary as a frame of reference.
Also an interesting happenstance, the deep end of the pool has much less variability than the shallow end due to greater thermal mass, less variable fresh ice influence and more efficient mixing. It should be a better frame of reference than the much more sensitive shallow end of the pool.
This is added just to show some of the delays caused by the asymmetry of the pool. The 1998 Super El Nino is a good perturbation to follow and here I aqm using BEST land only using the 1995 to 2010 baseline that everyone loves so much. The corresponding peak in the BEST data is a decade later than the perturbation. The SH SST first harmonic is about 4 years after with the NH about 3 years after the SH harmonic. The mean value lines for all three series is from 1880. So if the oceans are settling into what appears to be a comfortable heat capacity, there should be approximately a 0.2C lowering in average temperature from the 1995 to 2010 average by 2020 to 2025. Volcanoes and the longer solar minimum could reduce that a bit.