Do clouds disappear? 2

24/05/2010

Added 12 June 2010: There is now a thoughtful reply from Eimear Dunne.

Climate Change – News and Comments, and an echo of a Falsification Test

Wake up! Models don’t trump observations

The most important article since I launched this blog on 1 May may be Do clouds disappear when cosmic rays get weaker? — see here https://calderup.wordpress.com/2010/05/03/do-clouds-disappear/

It tells of unremitting attempts to falsify the Svensmark hypothesis by claiming that there’s no important effect on global cloud cover when eruptions from the Sun briefly cut the influx of cosmic rays, in “Forbush decreases”. The centrepiece is a summary of results published last year by Svensmark, Bondo and Svensmark. They show very plainly, in observations of the real world, that Forbush decreases have big impacts both on aerosols (chemical specks that grow into cloud condensation nuclei) and on low-level clouds.

That earlier post continues with the efforts in 2009-10 by Wolfendale and Arnold and their collaborators, who try to deny the Svensmark group’s result, by using relatively weak Forbush decreases. Svensmark can explain exactly how the impacts in those cases are masked by quasi-random meteorological noise, like tigers hidden in a jungle’s undergrowth.

Real-world results by Svensmark, Bondo & Svensmark (2009) for the remarkable loss of fine aerosols from the atmosphere (black curve) following five strong Forbush decreases in cosmic rays (red curve). Each aerosol datum point is the daily mean from about 40 AERONET stations world-wide, using stations with more than 20 measurements a day.

New nonsense comes in an abstract posted on the CERN website. It’s for a paper by researchers at Leeds, to be presented at a meeting about aerosols in Helsinki in three months’ time.

At issue are the Svensmark team’s results on aerosols (see right).  These show fine aerosols disappearing from the sky, because the shortage of cosmic rays lessens the chemical production of the  clusters of sulphuric acid and water molecules that seed the aerosols.

According to the people in Leeds, that can’t be right because they have a computer model that contradicts it.

The GLOMAP model was developed by Ken Carslaw, and the unlucky person named as lead author is a graduate student, Eimear Dunne.

An open letter to the lead author


Read the rest of this entry »

Advertisements