Archive for the ‘cosmic rays’ Category

Yet more evidence for the Svensmark effect

01/12/2011

Abstract:  We demonstrate evidence that past composite based studies centred around the onset of Forbush decrease (FD) events may have improperly isolated the maximal galactic cosmic ray (GCR) decrease associated with the FD events. After an adjustment of the composite to account for such shortcomings we find indications of anomalous cloud cover decreases (of around 3%) located in the upper levels of the troposphere at high southern latitudes. These cloud changes are detectable after latitudinal averaging, suggesting the possibility of a second order relationship between the rate of GCR flux and cloud cover in this region. The maximal cloud change is observed in advance of the maximal GCR decrease; this implies that if the observed cloud changes bear a causal relationship to the rate of GCR flux, then cloud properties may be sensitive to changes in GCR conditions rather than the maximal deviations themselves.”  “Forbush decreases and Antarctic cloud anomalies in the upper troposphere

Advertisements

New paper by Prof. Akasofu (Int'l Arctic Research Center, U. Alaska Fairbanks)

12/19/2010

“ABSTRACT
A number of published papers and openly available data on sea level changes, glacier retreat, freezing/break-up dates of rivers, sea ice retreat, tree-ring observations, ice cores and changes of the cosmic-ray intensity, from the year 1000 to the present, are studied to examine how the Earth has recovered from the Little Ice Age (LIA). We learn that the recovery from the LIA has proceeded continuously, roughly in a linear manner, from 1800-1850 to the present. The rate of the recovery in terms of temperature is about 0.5°C/100 years and thus it has important implications for understanding the present global warming. It is suggested, on the basis of a much longer period data, that the Earth is still in the process of recovery from the LIA; there is no sign to indicate the end of the recovery before 1900. Cosmic-ray intensity data show that solar activity was related to both the LIA and its recovery. The multi-decadal oscillation of a period of 50 to 60 years was superposed on the linear change; it peaked in 1940 and 2000, causing the halting of warming temporarily after 2000. These changes are natural changes, and in order to determine the contribution of the manmade greenhouse effect, there is an urgent need to identify them correctly and accurately and re-move them from the present global warming/cooling trend.  …

7. CONCLUSIONS
In this paper we learned:
1) The Earth experienced the Little Ice Age (LIA) between 1200-1400 and 1800-1850. The temperature during the LIA is expected to be 1°C lower than the present temperature. The solar irradiance was relatively low during the LIA.
2) The gradual recovery from 1800-1850 was approximately linear, the recovery (warming) rate was about 0.5°C/100 years. The same linear change continued from 1800-1850 to 2000. In this period, the solar irradiance began to recover from its low value during the LIA.
3) The recovery from the LIA is still continuing today.
4) The multi-decadal oscillation is superposed on the linear change. The multi-decadal oscillation peaked in about 1940 and also in 2000, causing the temporal halting of the recovery from the LIA.
5) The negative trend after the peak in 1940 and 2000 overwhelmed the linear trend of the recovery, causing the cooling or halting of warming.
6) The view presented in this paper predicts the temperature increase in 2100 to be 0.5°C ± 0.2°C, rather than 4° C ± 2.0°C predicted by the IPCC.”  “On the recovery from the Little Ice Age”  H/t Tom Nelson

Japan proxy study validates solar magnetic field climate link during Maunder Minimum

12/08/2010

Synchronized Northern Hemisphere climate change and solar magnetic cycles during the Maunder Minimum

Yasuhiko T. Yamaguchi, Yusuke Yokoyama, Hiroko Miyahara, Kenjiro Sho, and Takeshi Nakatsuka

Abstract:

The Maunder Minimum (A.D. 1645–1715) is a useful period to investigate possible sun–climate linkages as sunspots became exceedingly rare and the characteristics of solar cycles were different from those of today. Here, we report annual variations in the oxygen isotopic composition (δ18O) of tree-ring cellulose in central Japan during the Maunder Minimum. We were able to explore possible sun–climate connections through high-temporal resolution solar activity (radiocarbon contents; Δ14C) and climate (δ18O) isotope records derived from annual tree rings. The tree-ring δ18O record in Japan shows distinct negative δ18O spikes (wetter rainy seasons) coinciding with rapid cooling in Greenland and with decreases in Northern Hemisphere mean temperature at around minima of decadal solar cycles. We have determined that the climate signals in all three records strongly correlate with changes in the polarity of solar dipole magnetic field, suggesting a causal link to galactic cosmic rays (GCRs). These findings are further supported by a comparison between the interannual patterns of tree-ring δ18O record and the GCR flux reconstructed by an ice-core 10Be record. Therefore, the variation of GCR flux associated with the multidecadal cycles of solar magnetic field seem to be causally related to the significant and widespread climate changes at least during the Maunder Minimum.”  h/t Steven Goddard

Svensmark effect verified — again

12/07/2010

Recall last summer Svensmark published his paper verifying the Svensmark effect (correlation of cloud cover with galactic cosmic ray (GCR) intensity, modulated by the solar magnetic field) by observing the effect of Forbush decreases in GCR intensity on clouds over the oceans.  Now other researchers have independently verified the effect by observing periods of significant cloud changes, GCR flux changes, and surface air temperature changes over mid-latitude regions.  They say their results “provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship”.

More extensive coverage is provided by the Hockey Schtick and Watts Up With That.

Svensmark explains the faint young Sun paradox

04/02/2010

Abstract: Using kappa Ceti as a proxy for the young Sun we show that not only was the young Sun much more effective in protecting the Earth environment from galactic cosmic rays than the present day Sun; it also had flare and corona mass ejection rates up to three orders of magnitude larger than the present day Sun. The reduction in the galactic cosmic ray influx caused by the young Sun’s enhanced shielding capability has been suggested as a solution to what is known as the faint young Sun paradox, i.e. the fact that the luminosity of the young Sun was only around 75% of its present value when life started to evolve on our planet around four billion years ago [and yet, paradoxically, the Earth didn’t freeze over]. This suggestion relies on the hypothesis that the changing solar activity results in a changing influx of galactic cosmic rays to the Earth, which results in a changing low-altitude cloud coverage and thus a changing climate. Here we show how the larger corona mass ejection rates of the young Sun would have had an effect on the climate with a magnitude similar to the enhanced shielding capability of the young Sun.”  “How did the Sun affect the climate when life evolved on the Earth?”  h/t Lubos Motl

Svensmark explains the antarctic climate anomoly

03/29/2010

“Low-level clouds cover more than a quarter of the Earth and exert a strong cooling effect at the surface.  … Cloud tops have a high albedo and exert their cooling effect by scattering back into the cosmos much of the sunlight that could otherwise warm the surface.

But the snows on the Antarctic ice sheets are dazzlingly white, with a higher albedo than the cloud tops. There, extra cloud cover warms the surface, and less cloudiness cools it.  Satellite measurements show the warming effect of clouds on Antarctica, and meteorologists at far southern latitudes confirm it by observation.  …

The cosmic-ray and cloud-forcing hypothesis therefore predicts that temperature changes in Antarctica should be opposite in sign to changes in temperature in the rest of the world. This is exactly what is observed, in a well-known phenomenon that some geophysicists have called the polar see-saw, but for which “the Antarctic climate anomaly” seems a better name (Svensmark 2007).

To account for evidence spanning many thousands of years from drilling sites in Antarctica and Greenland, which show many episodes of climate change going in opposite directions, ad hoc hypotheses on offer involve major reorganization of ocean currents. While they might be possible explanations for low-resolution climate records, with error-bars of centuries, they cannot begin to explain the rapid operation of the Antarctic climate anomaly from decade to decade as seen in the 20th century (figure 6).

Cloud forcing is by far the most economical explanation of the anomaly on all timescales.  Indeed, absence of the anomaly would have been a decisive argument against cloud forcing – which introduces a much-needed element of refutability into climate science.”  “Cosmoclimatology:  a new theory emerges”  h/t WUWT

New paper: solar magnetic variation initiates interglacials

02/04/2010

“Using the fact that the galactic cosmic ray flux incident on the heliosphere boundary is known to have remained close to constant over the last 200 kyr, and that there exist independent records of geomagnetic variations over this period, Sharma25 was able to use a functional relation reflecting the existing data to give a good estimate of solar activity over this 200 kyr period.  …

Sharma was able to calculate the normalized solar modulation factor over the last 200 kyr. The result is shown in Fig. 8.

The 100 kyr periodicity is readily apparent in Fig. 8. It is also seen that the d18O record and solar modulation are coherent and in phase. Sharma concludes from this that “. . . variations in solar surface magnetic activity cause changes in the Earth’s climate on a 100-ka timescale”.  …

Summary

It has been shown above that low altitude cloud cover closely follows cosmic ray flux; that the galactic cosmic ray flux has the periodicities of the glacial/interglacial cycles; that a decrease in galactic cosmic ray flux was coincident with Termination II [the warming that initiated the Eemian, the last interglacial] ; and that the most likely initiator for Termination II was a consequent decrease in Earth’s albedo.

The temperature of past interglacials was higher than today most likely as a consequence of a lower global albedo due to a decrease in galactic cosmic ray flux reaching the Earth’s atmosphere. In addition, the galactic cosmic ray intensity exhibits a 100 kyr periodicity over the last 200 kyr that is in phase with the glacial terminations of this period. Carbon dioxide appears to play a very limited role in setting interglacial temperature.”  “INTERGLACIALS, MILANKOVITCH CYCLES, AND CARBON DIOXIDE”  h/t Niche Modeling

Voyager spacecraft make an important discovery

12/25/2009

Physicist Nir Shaviv has shown a correlation between the ice ages and the passing of the solar system through the spiral arms of the Milky Way galaxy, during which the number of cosmic rays reaching the Earth is substantially increased. The following article is interesting in that regard.

“The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA’s Voyager spacecraft have solved the mystery.

“Using data from Voyager, we have discovered a strong magnetic field just outside the solar system,” explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. “This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all.” …

Astronomers call the cloud we’re running into now the Local Interstellar Cloud or “Local Fluff” for short. …

The Fluff is held at bay just beyond the edge of the solar system by the sun’s magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the “heliosphere,” this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. …

The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. …

The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space.” “Voyager Makes an Interstellar Discovery” h/t Russ Steele

Voyager spacecraft make an important discovery

12/25/2009

Physicist Nir Shaviv has shown a correlation between the ice ages and the passing of the solar system through the spiral arms of the Milky Way galaxy, during which the number of cosmic rays reaching the Earth is substantially increased. The following article is interesting in that regard.

“The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA’s Voyager spacecraft have solved the mystery.

“Using data from Voyager, we have discovered a strong magnetic field just outside the solar system,” explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. “This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all.” …

Astronomers call the cloud we’re running into now the Local Interstellar Cloud or “Local Fluff” for short. …

The Fluff is held at bay just beyond the edge of the solar system by the sun’s magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the “heliosphere,” this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. …

The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. …

The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space.” “Voyager Makes an Interstellar Discovery” h/t Russ Steele

New paper by Qing-Bin Lu

12/22/2009

A new paper by Qing-Bin Lu of the University of Waterloo is making quite a splash (see e.g. WUWT). The paper purports to show that solar-magnetic-field-modulated cosmic rays are responsible not only for the Antarctic “ozone hole” (see prior paper by Lu here) but also for recent climate change through a mechanism involving cosmic rays and chlorofluorcarbons (CFCs) described in the abstract as follows:

“The cosmic-ray driven electron-induced reaction of halogenated molecules adsorbed on ice surfaces has been proposed as a new mechanism for the formation of the polar ozone hole. Here, experimental findings of dissociative electron transfer reactions of halogenated molecules on ice surfaces in electron-stimulated desorption, electron trapping and femtosecond time-resolved laser spectroscopic measurements are reviewed. It is followed by a review of the evidence from recent satellite observations of this new mechanism for the Antarctic ozone hole, and all other possible physical mechanisms are discussed. Moreover, new observations of the 11 year cyclic variations of both polar ozone loss and stratospheric cooling and the seasonal variations of CFCs and CH4 in the polar stratosphere are presented, and quantitative predictions of the Antarctic ozone hole in the future are given. Finally, new observation of the effects of CFCs and cosmic-ray driven ozone depletion on global climate change is also presented and discussed.”

I don’t think the paper adequately explains recent climate change however, primarily because I don’t think CFCs are primarily responsible for the Antarctic “ozone hole”. I think the observed correlation of cosmic rays and the Antarctic “ozone hole” has a much simpler explanation. For a good discussion of the latter issues see the article at Junk Science.