There is a new GRL paper in press by Elsner and Jagger entitled: 'United States and Caribbean tropical cyclone activity related to the solar cycle.'
The Abstract states:
The authors report on a finding that annual U.S hurricane counts are significantly related to solar activity. The relationship results from fewer intense tropical cyclones over the Caribbean and Gulf of Mexico when sunspot numbers are high. The finding is in accord with the heat-engine theory of hurricanes that predicts a reduction in the maximum potential intensity with
a warming in the layer near the top of the hurricane. An active sun warms the lower stratosphere and upper troposphere through ozone absorption of additional ultraviolet (UV) radiation. Since the dissipation of the hurricane’s energy occurs through ocean mixing and atmospheric transport, tropical cyclones can act to amplify the effect of relatively small changes in the sun’s output thereby appreciably altering the climate. Results have implications for life and property throughout the Caribbean, Mexico, and portions of the United States.
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6 comments:
It is widely recognized that Atlantic hurricanes are more common during times of La Nina than during El Nino and recent work suggests a link between El Nino conditions and solar activity, so the findings in this paper come as no surprise.
The whole picture suggests a link between solar activity and the El Nino Southern Oscillation. The big question is the mechanism ... solar winds influencing terrestrial winds? Something else?
John McLean said...
"It is widely recognized that Atlantic hurricanes are more common during times of La Nina than during El Nino...."
That link has a lot to do with with El Ninos producing wind shear in the Atlantic hurricane breeding grounds. There have been some active seasons suddenly squashed by the development of El Nino. The recent change in the Pacific Decadal Oscillation to its cool phase favors more La Ninas, so don't be surprised if we have a few more active years like this one.
Excatly what influence solar activity has on ENSO and the PDO is unclear, but given the deep minimum we're in now, we'll be learning a lot.
What is the link to the abstract?
Thanks
The paper is 'in press' so there is no link to the abstract - you have to be subscribed to the AGU, as I am, in order to see the peer reviewed draft.
I'll post a link when the paper is published. Should be very soon.
Very much looking forward to seeing this paper. The Heat Engine theory makes sense.
The link between UV light, cloud cover in the tropics and ENSO is via the temperature of the air at the 200hPa level, the upper level for the formation of cirrus cloud.
Temperatures at 200hPa follow the sun, peaking not at December 21st, the summer solstice or January 3d, the perihelion of the Earths orbit but later, drawn to March 21st when the magnetosphere couples most strongly with the solar wind. It appears that at this time the atmosphere between the tropics and the sun on the day-side is thinnest.
At 100hPa there is much more ozone and temperatures follow the pattern of heating and cooling of the Earth dictated by the distribution of land and sea. So there is a maximum in June - July.
UV cycles strongly within the sunspot cycle as does geomagnetic activity from the solar wind. It is not possible to quantify the contribution of both factors to atmospheric temperature in the upper troposphere but strong peaks in 200hPa temperature can be seen to be linked to one or the other, both, or the stronger of the two influences overcoming the weakness of the other.
More on Climate Audit on Blackboard under heading 'Solar Register'.
At least two studies document a change in temperature at 100hPa due to UV light at solar rotation time scales.
At 200hPa there is the unique conjunction of ozone and water vapour and vitally, at a temperature that tends to conserve the ozone presence. At 200hPa, and at a temperature of -50°C a tiny amount of water vapour can make a lot of absorbtive, emissive and reflective microcrystalline cloud. Equally, under UV heating that cloud disappears. BINGO EL NINO.
John,
The solar link is real but the connection is electrical - it's pretty obvious to the Plasma Universe theories but totally mysterious for the relatavists and Newtonians.
I am busy drafting an article for E&E on this aspect - comes out next year I believe.
The essential clue is to look at Kristian Birkeland's terrella experiments - but if you don't think that electric currents occur in space, then there's no point.
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