A Forbush decrease is a rapid decrease in the observed galactic cosmic ray intensity following a coronal mass ejection (CME). It occurs due to the magnetic field of the plasma solar wind sweeping some of the galactic cosmic rays away from Earth.
Well we have that going on in a dramatic way right now, it’s been going on since late yesterday. See the Oulu neutron monitor (a proxy for cosmic rays) graph:
That’s a screencap, you can monitor it live on the WUWT solar page here.
The term Forbush decrease was named after the American physicist Scott E. Forbush, who studied cosmic rays in the 1930s and 1940s.
steven mosher said on February 19, 2011 at 1:34 pm
“You guys realize that the cloud data (amount of cloud cover) DEPENDS upon radiative transfer equations. That is, the raw sensor inputs are ‘transformed’ by a physics model of radiative transfer. the same physics that gets used in GCMs.”
Wow, you guys have added some physical hypotheses to your GCMs. That must have been some feat, given that you have had none before this time. I guess is that you have some computer code that you label “physics” or “physical hypotheses” that bears no resemblance to any actual physical hypotheses whatsoever.
In Central Florida, we are in our third day with a cloudless sky. That is rather unusual because a lot of low-flying clouds are what we expect daily. Proves nothing, I know.
If anything comes of this, it will be up to Svensmark and team to explain it.
Nigel Calder, coauthor with Henrik Svensmark of The Chilling Stars, has a blog post on the Forbush effects.
http://calderup.wordpress.com/2010/05/03/do-clouds-disappear/
His blog summary of the Svensmark Hypothesis:
http://calderup.wordpress.com/2010/05/01/nutshell/
@vukcevic
What reason do you have for thinking that 10Be records are not accurate?
A flock of low flying clouds just popped up over Central Florida. First in three days. They are few and scraggly. But the flow promises to be continuous.
steven mosher says:
February 19, 2011 at 1:34 pm
“You guys realize that the cloud data (amount of cloud cover) DEPENDS upon radiative transfer equations. That is, the raw sensor inputs are ‘transformed’ by a physics model of radiative transfer. the same physics that gets used in GCMs.”
I knew it. Fiddle with your model and the data changes.
Tom W. says: February 20, 2011 at 7:36 am @ur momisugly
vukcevic What reason do you have for thinking that 10Be records are not accurate?
10Be count from the Greenland ice cores (Dye-3 and NGRIP) is not questioned as such. What should be under a ‘huge’ question mark is that the 10Be count can be a good proxy for the cosmic rays flux entering the Earth’s magnetosphere, implicitly strength of the heliospheric magnetic field at Earth’s orbit, and therefore indirectly a proxy for the solar activity intensity. To be exact, the 10Be count is a superb proxy for 10Be count itself, and a very poor and unsatisfactory proxy for any other variable as it is often suggested.
There are number of good reasons for this, some are recognised by the experts in the field, some as a yet have to be defined in more detail.
For start you can look at this paper: http://arxiv.org/ftp/arxiv/papers/1004/1004.2675.pdf
I have even stronger reservations formulated on the basis of my own research into 10Be data.
Vuk, the CRF affected by the earth magnetic field are lower energy. CRF affecting clouds would more likely be affected by intensity of the solar field, polarity, and position of the earth.
You also need to realize that albedo is extremely low in the oceans nearer the equator and due to angle, relatively high at the poles regardless snow/ice cover.
The Forbush decrease is exactly an effect that links changes in Solar activity to Earth’s climate — and to some world’s foremost Solar specialists’ indigestion.
Vuk, you also need to identify the type/energy of the CR passing through the earth. I believe Shaviv used metorites to identify this over very long terms, looking at the CRF the metorite was exposed to before it was protected by the atmostphere.
aaron says:February 20, 2011 at 9:35 am
Vuk, the CRF affected by the earth magnetic field are lower energy. CRF affecting clouds would more likely be affected by intensity of the solar field, polarity, and position of the earth.
Solar particles’ energy is of order of several 100s of MeV
High energy galactic cosmic rays are usually at few GeV.
The Earth’s magnetic field in the equatorial belt stops all particles up to 10 GeV, i.e. the most of GCR, so count is only at 20% of the polar regions, where the Earth’s field stops only protons of lower energies.
Albedo of polar regions as I implied in my previous post, is next to irrelevant (low energy input), it is the equatorial region which matters.
In the equarorial area Huancayo (Peru) Neutron Monitor was active from 1960 to 1993.
http://www.vukcevic.talktalk.net/HNC.htm
Although its output anti-correlates well with sunspot count, it does not to a satisfactory degree with temperatures.
If the correlation was stronger I would be first to jump on the bandwagon and declare solution to my temperature – magnetic field ideas:
http://www.vukcevic.talktalk.net/NFC1.htm
http://www.vukcevic.talktalk.net/LFC20.htm
Anecdotal again, yesterday was a lovely sunny day here in Dublin with lots of people out in the parks. Today damp, but no rain to speak of.
Also my broadband connection, normally very reliable, has been working intermittently
Here in Vancouver, BC where it ALWAYS RAINS, we have now had 3 days of perfectly cloudless weather following the CME. Exactly what SVENSMARK ET AL predicted.
Before that there was an enormous dump of new snow on the local mountains immediately before this, with fantastic powder skiing. Here is the report from Cypress (local mountain in Vancouver). On the ground, mid mountain they are reporting 420 cm – 13.8 feet of snow!!! Within the past 7 days – 6 feet of new snow!!! Total Snow Fall for the season 826 cm – 27 feet!!
Weather Conditions – Observed at Base
Weather Conditions: Clear Skies
Base Temperature: -1 C
Visibility: Unlimited
Winds: Calm
Snow Conditions (Mid Mtn.)
New Snow – Mid Mtn. (Over Night): 0 cm
New Snow – Mid Mtn. (24 hrs): 0 cm
New Snow – Mid Mtn. (7 days): 179 cm
Total Snow Fall (Season): 826 cm
Alpine Snow Conditions: Machine Groomed
Snow Depth – Mid Mtn.: 420 cm
How about a cap and trade on Cosmic Rays? A lot less rain here in the Pacific North West would make more sense than worrying about warming. 27 feet of snow within 5 miles of a city of 2 million people says things are cold enough, even with UHI.
Seriously, Baa Humbug has the best perspective. At best, this is a 4 day input of heat content primarily to the ocean. It will increase humidity over the oceans, but ultimately cause more precipitation. A short increase in temp in the upper trop, then a little decrease in at surface.
Useful data though.
This topic really isn’t about a four day Forbrush decrease affecting climate & weather. If Dr. Svensmark’s theory is shown to be correct by a Forbrush decrease, it is the possible cooling caused by a Solar Minimum that is the issue. Four decades of cooling would be significant. A return of cold and wetter weather to Europe as recorded during previous Solar minimums would be significant. It would also be devastating.
Jeff (of Colorado) says:
February 20, 2011 at 9:15 pm
… possible cooling caused by a Solar Minimum that is the issue. Four decades of cooling would be significant. A return of cold and wetter weather to Europe as recorded during previous Solar minimums would be significant. It would also be devastating.
Let’s hope not, because the new solar forecasting technique outlined on my blog is forecasting a four decade drop in TSI…
http://tallbloke.wordpress.com/2011/02/21/tallbloke-and-tim-channon-a-cycles-analysis-approach-to-predicting-solar-activity/
I would like to point your attention to this paper:
http://arxiv.org/abs/1007.2099
Since 1984 D-r Komitov has very good record in climate predictions based on solar-earth connections. The paper above is about the solar eruptions, the north-south sunspot area asymmetry and the climate. It tells that the effects of such large eruptions are much more complicated and their climate effects are not only Cosmic rays related.
Interesting technique. It looks like FFT decomposition of the TSI signal. If TSI is cyclic, modulated by the planetary orbits there should be 7 or 8 signals in the TSI.
This technique may simply be curve fitting with no predictive power, similar to what the climate models have shown. However, the difference with this technique is that it assumes climate is cyclic, while the mainstream models are forcings/feedback based.
Personally I believe a cyclic model of climate is much more likely, given that just about everything we observe in the natural world is cyclic.
It is not surprising that the time scales shown in the cycles differ slightly from historical observations, as the Lean 2000 TSI reconstruction is unlikely to be 100% accurate. What is more surprising, and worrisome is that the cycles uncovered match as well as they do. If this prediction matches reality, then the world is going to get a hurt real bad and CO2 mitigation strategies are the worst possible policy to enact at this time.
ferd berple says: February 21, 2011 at 7:27 am
If this prediction matches reality, then the world is going to get a hurt real bad and CO2 mitigation strategies are the worst possible policy to enact at this time.
I wouldn’t be to concerned on account of the TSI, although current measurements are accurate, past reconstructions vary considerably. Compared to the CETs, the world’s longest continues temperature record, correlation with any of the available reconstructions does not appear to be very consistent.
http://www.vukcevic.talktalk.net/TSI-CET.htm
2003 was solar flares prolific. If you have 10min to spare it is worth watching hole of the movie. Pay extra attention around Halloween (X40+) and the Christmas. I downloaded it (it is 48Mb, but there is 27MB medium version (=medium).
http://www.youtube.com/watch_popup?v=dvBI4Kirpbw&vq=large
Sun could be at the start of another year of fireworks?
tallbloke says:
February 21, 2011 at 3:15 am
the new solar forecasting technique outlined on my blog is forecasting a four decade drop in TSI…
Based on physical considerations [not cyclomania 🙂 ], I tend to think that SC25 will be larger than SC24, possible significantly higher.
Nice to see a smiley in there Leif. Good on you for making a prediction too. 🙂