Comments
More Evidence for a Solar Amplification Mechanism
Nir Shaviv’s latest paper has been published in the Journal of Geophysical Research (Space Physics). It is entitled: ‘Using the oceans as a calorimeter to quantify the solar radiative forcing.’ The Abstract states:
Over the 11-year solar cycle, small changes in the total solar irradiance (TSI) give rise to small variations in the global energy budget. It was suggested, however, that different mechanisms could amplify solar activity variations to give large climatic effects, a possibility which is still a subject of debate. With this in mind, we use the oceans as a calorimeter to measure the radiative forcing variations associated with the solar cycle. This is achieved through the study of three independent records, the net heat flux into the oceans over 5 decades, the sea-level change rate based on tide gauge records over the 20th century, and the sea-surface temperature variations. Each of the records can be used to consistently derive the same oceanic heat flux. We find that the total radiative forcing associated with solar cycles variations is about 5 to 7 times larger than just those associated with the TSI variations, thus implying the necessary existence of an amplification mechanism, although without pointing to which one.
The paper concludes:
In summary, we find clear evidence indicating that the total flux entering the oceans in response to the solar cycle is about an order of magnitude larger than the globally averaged irradiance variations of 0.17 W/m2. The sheer size of the heat flux, and the lack of any phase lag between the flux and the driving force further implies that it cannot be part of an atmospheric feedback and very unlikely to be part of a coupled atmosphere-ocean oscillation mode. It must therefore be the manifestation of real variations in the global radiative forcing. [74] It should be stressed that the observed correlation between the oceanic heat flux and solar activity does not provide proof for any particular amplification mechanism, including that of the CRF/climate link. It does however provide very strong support for the notion that an amplification mechanism exists. Given that the CRF/climate links predicts the correct radiation imbalance observed in the cloud cover variations, it is a favorable candidate. [75] With respect to simulating climate dynamics, the results have two very interesting ramifications. First, they imply that any attempt to explain historic temperature variations should consider that the solar forcing variations are almost an order of magnitude larger that just the TSI variations now used almost exclusively. It would imply that the climate sensitivity required to explain historic temperature variations is smaller than often concluded. [76] Second, an additional constraint can be used to narrow the range of GCMs’ model parameters. Under solar cycle like periodic forcing, a GCM should predict that the ratio between the oceanic heat flux and sea-surface temperature variations is that which is observed, namely, a net oceanic flux of 1.05 ± 0.25 W/m2 for every 0.09 ± 0.01C change in the sea-surface temperature (or somewhat larger land surface temperature variations). This should prove useful in constraining GCM based predictions, such as that of climate sensitivity.
March 3rd, 2009 at 9:32 am
[...] recent paper by Nir Shaviv’s in the Journal of Geophysical Research has this to [...]
April 26th, 2009 at 5:47 am
Nir Shaviv actually wrote about it in his website: http://www.sciencebits.com/calorimeter