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Post by nautonnier on Nov 22, 2017 16:30:16 GMT
Lots of models. But the point is that the SSTs drive the genesis of convective weather. These do not appear to have been lower than normal in the appropriate areas. Once the convective weather starts it only gets to form a hurricane if the upper tropospheric winds are favorable - that is there is no shear that will take the top off the storms weakening them before they can go through cyclogenesis. The shear in the West Atlantic and Caribbean is driven by the Pacific and ENSO not the Atlantic (AMOC etc). So I find this paper a little difficult to believe.
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Post by sigurdur on Nov 22, 2017 19:15:16 GMT
The state of the Atlantic provides the necessary Dynamics to create large scale US drought conditions. There is a symbiotic relationship with the Pacific in regards to Hurricanes.
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Post by missouriboy on Nov 22, 2017 20:01:28 GMT
This one will take some time to digest. I did immediately note that the authors did not make any direct comparisons to solar activity. The comparisons to the AMOC and AMO are interesting, and may be more so as I digest this, but can they be 'direct' drivers of anything given that they are likely driven by other forces? In light of the recent article regarding hurricane activities and low solar activity, I thought I'd at least run a fast comparison of their data to the geomagnetic index. I did appreciate the links to data sources at the end of the article, which I intend to steal. In the following chart the number of major hurricanes (red points = 5 or more, green points = < 5) seem to largely occur during periods of low solar activity with many located along abrupt edges, where geomagnetic activity is rapidly and dramatically declining or increasing. Periods of greater geomagnetic activity appear to be associated with fewer major hurricanes. Years with less than 5 majors also seem to show this pattern. This could be rerun with the ACE index as well.
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Post by sigurdur on Nov 22, 2017 21:31:53 GMT
Indirectly ties in to Geoff Sharp and others that Solar drives the AMO.
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Post by nautonnier on Nov 23, 2017 1:25:24 GMT
Indirectly ties in to Geoff Sharp and others that Solar drives the AMO. Or that what drives the Solar also drives the AMO - possibly in a similar way.
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Post by Ratty on Nov 23, 2017 9:15:01 GMT
The role of Atlantic overturning circulation in the recent decline of Atlantic major hurricane frequencyAbstract
Observed Atlantic major hurricane frequency has exhibited pronounced multidecadal variability since the 1940s. However, the cause of this variability is debated. Using observations and a coupled earth system model (GFDL-ESM2G), here we show that the decline of the Atlantic major hurricane frequency during 2005–2015 is associated with a weakening of the Atlantic Meridional Overturning Circulation (AMOC) inferred from ocean observations. Directly observed North Atlantic sulfate aerosol optical depth has not increased (but shows a modest decline) over this period, suggesting the decline of the Atlantic major hurricane frequency during 2005–2015 is not likely due to recent changes in anthropogenic sulfate aerosols. Instead, we find coherent multidecadal variations involving the inferred AMOC and Atlantic major hurricane frequency, along with indices of Atlantic Multidecadal Variability and inverted vertical wind shear. Our results provide evidence for an important role of the AMOC in the recent decline of Atlantic major hurricane frequency.
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Post by sigurdur on Nov 23, 2017 9:32:34 GMT
Thanks for the abstract to my post.
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Post by Ratty on Nov 23, 2017 10:01:30 GMT
Thanks for the abstract to my post. Sorry Sig. Too long ago for me to remember. I thought it looked familiar ......
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Post by nautonnier on Nov 23, 2017 13:56:40 GMT
Well this is the end of Hurricane season for 2017.
Happy Thanksgiving!
I hope that Glen and the others who had problems this season are recovering back to 'normal'
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Post by missouriboy on Nov 23, 2017 15:28:50 GMT
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Post by sigurdur on Nov 23, 2017 15:55:38 GMT
1. I want to see the NOAA documentation. 2. Cement has the ability to channel water. 3.
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Post by sigurdur on Nov 23, 2017 15:56:24 GMT
Well this is the end of Hurricane season for 2017. Happy Thanksgiving! I hope that Glen and the others who had problems this season are recovering back to 'normal' Glenn was doing well last time I talked to him.
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