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A problem of multiplicity

Filed under: — rasmus @ 20 November 2009

One thing a scientist doesn’t want to mess up is the problem of multiplicity (also known as ‘field significance‘). It’s just like rolling a die 600 times, and then getting excited about getting roughly 100 sixes. However, sometimes it’s much more subtle than just rolling dice.

This problem seems to be an issue in a recent by paper with the title ‘Evidence for solar forcing in variability of temperatures and pressures in Europe‘ by Le Mouel et al. (2009) in the Journal of Atmospheric and Solar-Terrestrial Physics.

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Why the continued interest?

Filed under: — rasmus @ 9 October 2009

I believe the idea that galactic cosmic rays (GCR) play a role for the present global warming is unlikely to fade soon, despite a growing number of scientific arguments that normally would falsify a hypothesis and lay it dead (see links here and here). Despite all the arguments against the role of GCR, there was a solicited talk about ‘cosmoclimatology’ at the European Meteorological Society’s (EMS) annual meeting in Toulouse. Henrik Svensmark is further invited by the Norwegian Academy of Science and Letters (NASL) to provide an introduction to their seminar on climate. So why is the GCR-hypothesis still perceived as an interesting explanation?

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Climate Services

Filed under: — rasmus @ 9 September 2009

I recently attended the World Climate Conference-3 (WCC-3), hosted by the World Meteorological Organization (WMO) in Geneva. Most of the talk was of providing “climate services” (CS) and coordinating these globally. But what are climate services, and how much of what was envisaged is scientifically doable?
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Still not convincing

Filed under: — rasmus @ 1 August 2009

cloud In a new GRL paper, Svensmark et al., claim that liquid water content in low clouds is reduced after Forbush decreases (FD), and for the most influential FD events, the liquid water content in the oceanic atmosphere can diminish by as much as 7%. In particular, they argue that there is a substantial decline in liquid water clouds, apparently tracking a declining flux of galactic cosmic rays (GCR), reaching a minimum days after the drop in GCR levels. The implication would be that GCR can affect climate through modulating the low-level cloudiness. The analysis is based on various remote sensing products.

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ACRIM vs PMOD

Filed under: — rasmus @ 6 May 2009 - (Italian)

Two recent papers (Lockwood & Fröhlich, 2008 – ‘LF08′; Scafetta & Willson, 2009 – ‘SW09′) compare the analysis of total solar irradiance (TSI) and the way the TSI measurements are combined to form a long series consisting of data from several satellite missions. The two papers come to completely opposite conclusions regarding the long term trend. So which one (if either) is right, then? And does it really matter?

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