The Tale Told by the Heliospheric Tilt Angle

Guest essay by David Archibald

Some of the ancients worshipped the Sun as the source of all life. It is much the same today. Most of the energy we use as a civilisation is fossilised solar energy, conveniently provided by Nature as solids and liquids and gasses – whtatever you want.

Only the little bit from nuclear power has a non-solar source. So it is appropriate that we should learn as much about the Sun as possible. We have only a few decades of data on solar activity in the electromagnetic spectrum to aid that understanding.

The data on the heliospheric current sheet tilt angle provided by the Wilcox Solar Observatory has recently updated and it shows that the Sun isn’t just a sloppy old ball of plasma in which things happen in a random walk. It is a quite disciplined ball of plasma.


Figure 1: Heliospheric Current Sheet Tilt Angle 1976 – 2018

Figure 1 shows the heliospheric current sheet tilt angle from the start of the records kept by the Wilcox Solar Observatory just west of Stanford University. It is apparent that the declining phases of Solar Cycles 23 and 24 formed descending wedges with the wedges narrowing to the point at which the heliospheric current sheet flattened. It is said that the solar cycle isn’t over until the heliospheric current sheet has flattened. For Solar Cycle 24 the month of flattening will be from July to September 2019. We have just over a year to minimum now and Solar Cycle 24 will be slightly shorter than average.

In Solar Cycle 23 activity jumped out of the wedge but the month of flattening was as predicted by the descending wedge. The previous cycles did not form apparent wedges by activity was constrained by a downtrend line. Solar Cycles 21, 22 and 23 are from a time of anomalously high solar activity. Solar Cycle 24 may represent a return to normal solar activity.


Figure 2: Interplanetary Magnetic Field 1966 to 2018

The values at minimum for the last three solar minima line up suggesting that there may be a process that controls this. If this process exists, and holds for the 24/25 solar minimum, then the low will be 2.9 in late 2019. Last month the interplanetary magnetic field plunged to a new low for the instrument record. The Earth’s magnetic shield is down and falling further with the consequence that we are headed for a new high in the Oulu neutron count in late 2020 of about 7,000.

Svensmark theory says that will result in further terrestrial cooling due to an increased albedo of the planet due to high cloud cover. The bellwether of ice sheets, the Greenland Ice Sheet, is already responding with ice accumulation at a near-record rate in 2018:


Figure 3: The accumulated surface mass balance of the Greenland Ice Sheet from September 2017 to now

David Archibald is the author of American Gripen: The Solution to the F-35 Nightmare

via Watts Up With That?

August 4, 2018 at 11:54AM

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