History, Politics And Current Affairs

Opinions expressed here are personal views of contributors and do not necessarily represent the companies, organizations or governments they work for. Nor do they necessarily represent those of the Board Administration.
It is currently Sat Jan 20, 2018 3:49 am

All times are UTC - 5 hours




Post new topic Reply to topic  [ 8 posts ] 
Author Message
PostPosted: Sun Dec 17, 2017 7:22 pm 
Offline
Site Admin
User avatar

Joined: Sat Oct 04, 2008 9:55 am
Posts: 17829
Location: Chicagoland
The sun is blank, NASA data shows it to be dimming
Anthony Watts / 2 days ago December 15, 2017

As the sun gets successively more blank with each day, due to lack of sunspots, it is also dimming. According to data from NASA’s Spaceweather, so far in 2017, 96 days (27%) of the days observing the sun have been without sunspots. Here is the view today from the NASA Solar Dynamics Observatory satellite:


Solar Dynamics Observatory HMI Continuum image more at WUWT’s solar reference page: https://wattsupwiththat.com/reference-pages/solar/

Today at Cape Canaveral, SpaceX launched a new sensor to the International Space Station named TSIS-1. Its mission: to measure the dimming of the sun’s irradiance. It will replace the aging SORCE spacecraft. NASA SDO reports that as the sunspot cycle plunges toward its 11-year minimum, NASA satellites are tracking a decline in total solar irradiance (TSI).

Across the entire electromagnetic spectrum, the sun’s output has dropped nearly 0.1% compared to the Solar Maximum of 2012-2014. This plot shows the TSI since 1978 as observed from nine previous satellites:



In the top plot, we drew the daily average of measured points in red (so there are a lot of points, 14187 to be precise). On the left is a red vertical bar showing a 0.3% change in TSI. The black curve is the average of TSI over each year. The dashed horizontal line shows the minimum value of year-averaged TSI data. The vertical black bar shows the 0.09% variation we see in that average. The bottom plot shows the annual sunspot number from the SIDC in Belgium in blue. Source: NASA Solar Dynamics Observatory Mission Blog.

What do we learn from these plots? First, TSI does change! That’s why we stopped calling it the solar constant. Second, as the sunspot number increases, so does TSI. But the converse is also true. As the sunspot number decreases so does TSI. We have watched this happen for four sunspot cycles. This waxing and waning of TSI with sunspot number is understood as a combination of dark sunspots reducing TSI below the dashed line and long-lived magnetic features increasing TSI. SORCE has even observed flares in TSI.

Third, the horizontal dashed line is not an average, it is drawn at the lowest value in the year-averaged TSI data (that happened in 2009). When there are no sunspots the Sun’s brightness should be that of the hot, glowing object we always imagined it to be. We would expect TSI to be the same at every solar minimum. There is much discussion over whether the value of TSI at solar minimum is getting smaller with time, but it is not getting larger.

These data show us that the Sun is not getting brighter with time. The brightness does follow the sunspot cycle, but the level of solar activity has been decreasing the last 35 years. The value at minimum may be decreasing as well, although that is far more difficult to prove. Perhaps the upcoming solar minimum in 2020 will help answer that question.

The rise and fall of the sun’s luminosity is a natural part of the solar cycle. A change of 0.1% may not sound like much, but the sun deposits a lot of energy on the Earth, approximately 1,361 watts per square meter. Summed over the globe, a 0.1% variation in this quantity exceeds all of our planet’s other energy sources (such as natural radioactivity in Earth’s core) combined. A 2013 report issued by the National Research Council (NRC), “The Effects of Solar Variability on Earth’s Climate,” spells out some of the ways the cyclic change in TSI can affect the chemistry of Earth’s upper atmosphere and possibly alter regional weather patterns, especially in the Pacific.

NASA’s current flagship satellite for measuring TSI, the Solar Radiation and Climate Experiment (SORCE), is now more than six years beyond its prime-mission lifetime. TSIS-1 will take over for SORCE, extending the record of TSI measurements with unprecedented precision. It’s five-year mission will overlap a deep Solar Minimum expected in 2019-2020. TSIS-1 will therefore be able to observe the continued decline in the sun’s luminosity followed by a rebound as the next solar cycle picks up steam. Installing and checking out TSIS-1 will take some time; the first science data are expected in Feb. 2018.

In other news, as the magnetic activity of the sun decreases, influx of Galactic Cosmic Rays (GCR’s) increase as has been observed by balloon measurements over California:



Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth’s magnetic field, which helps protect us from deep-space radiation.

The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.

The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth’s atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.

NASA’s spaceweather.com website follows the progress of the sun on a regular basis. Our WUWT Solar Reference Page also has data updated daily.


https://wattsupwiththat.com/2017/12/15/ ... e-dimming/

_________________
- Dennis

Victory at all costs, victory in spite of all terror, victory however long and hard the road may be; for without victory there is no survival."
-Sir Winston Churchill


Top
 Profile Send private message  
Reply with quote  
PostPosted: Sun Dec 17, 2017 8:41 pm 
Offline
User avatar

Joined: Sun Oct 05, 2008 6:48 pm
Posts: 4263
Location: UK
http://spaceweather.com/
==

FWIW, the next decade may see the 'long cycles' simulation teams' predictions validated or not. They reckon there's another 'Maunder Minimum' pending, with an associated 'Little Ice Age'.

https://principia-scientific.org/modern ... ng-coming/

Okay, such would offset some of the still-rising CO2 levels' consequences, but I really, really don't want to hike to and from the supermarket towing the old kiddy-sledge...

{ Memo to self: In case of dire winter, order wire-brush for electric drill to clean up those rusty runners. Oh, and a bike-lock to chain sledge to railings... ;) }

_________________
'P for Pleistocene' A camp-out goes impossibly wrong...


Top
 Profile Send private message  
Reply with quote  
PostPosted: Sun Dec 17, 2017 9:26 pm 
Offline
User avatar

Joined: Wed Oct 08, 2008 5:35 am
Posts: 5642
Location: Sweden
Once every few years winters up here in the north are already fairly dire.
If we're looking at winters approaching such as those experienced during the little ice age, or during the world war 2 winters, I'll consider an extended stay somewhere sunnier. :P

_________________
The Night Watch - A Star Trek Story


Top
 Profile Send private message  
Reply with quote  
PostPosted: Mon Dec 18, 2017 5:09 pm 
Offline

Joined: Sat Oct 04, 2008 2:48 am
Posts: 2580
Interesting timing. The next few years will see a pause (cue hysteria) in the temperature rise as we approach the cold bit of the cycle in the AMO/PDO interaction.

I've always wondered about the way the sun is discussed. It doesn't just radiate light and heat, it also emits a continual sleet of charged particles. Some of these must make it through the Van Allen belt and hit the atmosphere where they'll cause clouds to form, which will increase the earth's albedo, but also cause some greenhouse effect. Rather hilariously nobody has settled on which effect is stronger. So you can't just plot the sun's output against time and claim that's the whole story.

Also bear in mind we are talking about tiny changes in insolation, 3 in 1360 W m-2 .


Top
 Profile Send private message  
Reply with quote  
PostPosted: Mon Dec 18, 2017 5:15 pm 
Offline
User avatar

Joined: Mon Feb 16, 2009 5:32 pm
Posts: 6509
Location: Currently 3rd Rock from the sun
They can't discuss the sun's role in climate. If they did, they would have to admit it's the driving factor, not man's activities. It's not about climate change, it's about allow them to dictate to people what they can and can't do.

_________________
Faugh a Ballagh


Top
 Profile Send private message  
Reply with quote  
PostPosted: Mon Dec 18, 2017 6:05 pm 
Offline

Joined: Wed Oct 08, 2008 7:53 am
Posts: 607
Gee
Ya suppose those squirrelheads over in GLOBULL WARMUN CENTRAL even consider what happens if you turn down the brilliance on the star about 8 1/2 light-minutes thataway??

Didn't think so
But it doesn't make them less retarded. Quite the opposite, actually


Top
 Profile Send private message  
Reply with quote  
PostPosted: Mon Dec 18, 2017 6:30 pm 
Offline

Joined: Sat Oct 04, 2008 2:48 am
Posts: 2580
But the change is only 3 in 1360, is that really enough to affect things? Bad maths time, how much would that extra power warm the atmosphere?

mass_at 5.15E+18
shc_at 1000
earth_Radius 6.37E+06
Insolation_change 3
incoming_power_delta 3.82E+14
temp_delta_per_second 7.43E-08
secondsperyear 30780000
temp_delta_per_year 2.29E+00

WOW

Obviously that is a massive overestimate, but the answer is that small changes in that 1360 number could have an effect on temperature.


Top
 Profile Send private message  
Reply with quote  
PostPosted: Mon Dec 18, 2017 7:12 pm 
Offline

Joined: Sat Oct 04, 2008 2:48 am
Posts: 2580
I suppose it is incumbent on me to explain why that is an overestimate

1) I used 3 W/m2/year. That is wrong
2)The earth's albedo is 0.3, so 70% of the change gets reflected off the top of the atmosphere
3) any increase in the atmosphere's temperature will increase the amount of heat radiated by the earth
4) On the other hand I only used a year, the effect would be cumulative.

Anyway, the answer is till that long term changes in insolation are of sufficient magnitude to alter the temperature of the atmosphere.

Which is pretty interesting.

Sadly of course we only have 70 years of direct measurement of that insolation, everything else is reconstructions from proxies. Of course that doesn't really matter, we have the same problem with albedo.


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: Beowulf and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group