Archive for the ‘cloudiness – albedo’ 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

Spencer on Dressler's new paper

12/09/2010

“[Andrew] Dessler’s [new] paper [here] claims to show that cloud feedback is indeed positive, and generally supportive of the cloud feedbacks exhibited by the IPCC computerized climate models.  …

Unfortunately, the central evidence contained in the paper is weak at best, and seriously misleading at worst. It uses flawed logic to ignore recent advancements we have made in identifying cloud feedback.  …

The answer lies in an issue that challenges researchers in most scientific disciplines – separating cause from effect.

Dessler’s claim (and the IPCC party line) is that cloud changes are caused by temperature changes, and not the other way around. Causation only occurs in one direction, not the other.

In their interpretation, if one observes a warmer year being accompanied by fewer clouds, then that is evidence of positive cloud feedback. Why? Because if warming causes fewer clouds, it lets in more sunlight, which then amplifies the warming. That is positive cloud feedback in a nutshell.

But what if the warming was caused by fewer clouds, rather than the fewer clouds being caused by warming? In other words, what if previous researchers have simply mixed up cause and effect when estimating cloud feedback?

What we demonstrated in our JGR paper earlier this year is that when cloud changes cause temperature changes, it gives the illusion of positive cloud feedback – even if strongly negative cloud feedback is really operating!

What we showed was basically a new diagnostic capability that can, to some extent, separate cause from effect. This is a fundamental advancement – and one that the news media largely refused to report on.  …

The weak reasoning the paper employs – and the evidence we published which it purposely ignores! – combined with the great deal of media attention it will garner at a time when the IPCC needs to regain scientific respectability (especially after Climategate), makes this new Science paper just one more reason why the public is increasingly distrustful of the scientific community when it comes to research having enormous policy implications.”  “The Dessler Cloud Feedback Paper in Science: A Step Backward for Climate Research

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.

Lindzen and Choi's new paper out — confirms negative feedback, unlike AGW climate models

05/03/2010

Abstract: To estimate climate sensitivity from observations, Lindzen and Choi [2009] used the deseasonalized fluctuations in sea surface temperatures (SSTs) and the concurrent responses in the top-of-atmosphere outgoing radiation from the ERBE satellite instrument. Distinct periods of warming and cooling in the SST were used to evaluate feedbacks. This work was subject to significant criticism by Trenberth et al. [2009], much of which was appropriate. The present paper is an expansion of the earlier paper in which the various criticisms are addressed and corrected. In this paper we supplement the ERBE data for 1985-1999 with data from CERES for 2000-2008. Our present analysis accounts for the 36 day precession period for the ERBE satellite in a more appropriate manner than in the earlier paper which simply used what may have been undue smoothing. The present analysis also distinguishes noise in the outgoing radiation as well as radiation changes that are forcing SST changes from those radiation changes that constitute feedbacks to changes in SST. Finally, a more reasonable approach to the zero-feedback flux is taken here. We argue that feedbacks are largely concentrated in the tropics and extend the effect of these feedbacks to the global climate. We again find that the outgoing radiation resulting from SST fluctuations exceeds the zero-feedback fluxes thus implying negative feedback. In contrast to this, the calculated outgoing radiation fluxes from 11 atmospheric GCMs [global climate models] forced by the observed SST are less than the zero-feedback fluxes consistent with the positive feedbacks that characterize these models. The observational analysis implies that the models are exaggerating climate sensitivity.”  “On the observational determination of climate sensitivity and its implications”  h/t The Hockey Schtick

Posts on Lindzen and Choi 2009 here, here, and here.

Stephen Wilde's new climate model

04/07/2010

“In my articles to date I have been unwilling to claim anything as grand as the creation of a new model of climate because until now I was unable to propose any solar mechanism that could result directly in global albedo changes without some other forcing agent or that could account for a direct solar cause of discontinuities in the temperature profile along the horizontal line of the oceanic thermohaline circulation.  I have now realised that the global albedo changes necessary and the changes in solar energy input to the oceans can be explained by the latitudinal shifts (beyond normal seasonal variation) of all the air circulation systems and in particular the net latitudinal positions of the three main cloud bands namely the two generated by the mid latitude jet streams plus the Inter Tropical Convergence Zone (ITCZ).

The secret lies in the declining angle of incidence of solar energy input from equator to poles.

It is apparent that the same size and density of cloud mass moved, say, 1000 miles nearer to the equator will have the following effects:

i) It will receive more intense irradiation from the sun and so will reflect more energy to space.

ii) It will reduce the amount of energy reaching the surface compared to what it would have let in if situated more poleward.

iii) In the northern hemisphere due to the current land/sea distribution the more equatorward the cloud moves the more ocean surface it will cover thus reducing total solar input to the oceans and reducing the rate of accretion to ocean energy content.

iv) It will produce cooling rains over a larger area of ocean surface.

As a rule the ITCZ is usually situated north of the equator because most ocean is in the southern hemisphere and it is ocean temperatures that dictate it’s position by governing the rate of energy transfer from oceans to air. Thus if the two mid latitude jets move equatorward at the same time as the ITCZ moves closer to the equator the combined effect on global albedo and the amount of solar energy able to penetrate the oceans will be substantial and would dwarf the other proposed effects on albedo from changes in cosmic ray intensity generating changes in cloud totals as per Svensmark and from suggested changes caused in upper cloud quantities by changes in atmospheric chemistry involving ozone which various other climate sceptics propose.

Thus the following NCM will incorporate my above described positional cause of changes in albedo and rates of energy input to the oceans rather than any of the other proposals. That then leads to a rather neat solution to the other theories’ problems with the timing of the various cycles as becomes clear below.”

Read more here:  “A new and effective climate model

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

Spencer: clouds dominate climate change

01/10/2010

“Last year I posted an analysis of satellite observations of the 2007-08 global cooling event, showing evidence that it was due to a natural increase in low cloud cover. Here I will look at the bigger picture of what how the satellite-observed variations in Earth’s radiative budget compare to that expected from increasing carbon dioxide. Is there something that we can say about the relative roles of nature versus humanity based upon the evidence?

What we will find is evidence consistent with natural cloud variations being the dominant source of climate variability since 2000.”  Read the rest here:  “Clouds Dominate CO2 as a Climate Driver Since 2000

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