Real Climate brings word about Jens-Uwe Grooß and Rolf Müller trying to drive the silver spike into Qing Bing Lu's cosmic ray driven ozone destruction mechanism, but Eli predicts that zombies always rise. Eli had a bunch of things to say about this idea in early 2010, none very nice.
We will get on to a bit of the science in a moment, but what revenge the bunnies ask. Well, QB is at Waterloo, which also houses, and has housed a whole bunch of very good photochemists, spectroscopists and atmospheric scientists. Also, as Eli said at the time
Waterloo is the lead institution for the Atmospheric Chemistry Experiment (ACE) on board the Canadian SciSat, up there measuring the CFCs Lu is babbling about (and Eli is being nice).The Rabett talked to one of the ACE participants at the time. Conversation went "You gotta be kidding". "Well yeah he is a clown, but he doesn't listen to anyone and we tried". Eli had the impression that other members of the ACE team would not have been as kind.
Grooß and Müller make considerable use of ACE data in their refutation, and at the end acknowledge some of Santa's helpers
We also thank the ACE-FTS science team for producing and providing their high-quality data sets. The ACE mission was funded by the Canadian Space Agency.It must have given them some pleasure.
As to the substance of Grooß and Müller's put down, it starts from the observation that they made in a series of papers (see also RR links): heavily smoothed correlations without considering confounding factors is not causation. The loss of CFCs as a function of time and place does not fit Lu's mechanism, especially if you don't fiddle the data. As they say
the ACE-FTS measurements of CFC-12 and CH4 in the Antarctic stratosphere in winter and spring (Fig. 1) show no signature of a chemical loss of CFC-12 for a given CH4 mixing ratio. Figure 19 of Lu (2010a) shows a comparison of HALOE CH4 and CLAES CFC-12. Here it is important that this comparison is based on measurements of the two tracers that are observed in comparable air masses. However, these two instruments have different viewing geometries and therefore different latitudinal coverage. Moreover, the HALOE and CLAES data shown by Lu (2010a) represent different years (1992-1998 versus 1992).This, if you watched the videos, is Pat Michaels' tactic (Michaels conveniently forgets to mention sulfate aerosol effects when discussing atmospheric warming: start @ ~ 1:30 and listen to Ben Santer @ ~3:30).
Grooß and Müller show that the concentrations of CFCs do not change in a manner consistent with Lu's predictions/mechanisms, but entirely consistent with photolytic decomposition. The mechanism is a "giant Cl- and F- enhancements in electron induced dissociation" of CFCs on ices.
OK say Grooß and Müller, let's look at the ACE data. If Lu is correct, the concentration of CFCs relative to tracers such as N2O and CH4 will decrease during winter and early spring in the Antarctic. So they look at N2O, and nope nothing there. Well says QB, in one of the 2010 papers, maybe N2O will have the same large enhancement. OK say Grooß and Müller, lets look at CH4. Nope, nothing there.
Well, what if Lu says the same thing happens for methane. Unfortunately ACE provides absolute measurements for methane and there is no large decrease in the Antarctic region for winter and early spring. In short, the CFCs are not rapidly decomposing on ice particles during the winter and spring, so Lu's mechanism is not working.
But wait, there is more. Chlorine and ClO, the guys that catalytically destroy ozone, become available in the Arctic winter when there are no ice particles in the stratosphere and early in the Antarctic winter before the ice particles form. Hmm, that is not what Lu's hypothesis would predict.
And then there are additional confusions, Lu presents a simple equation to predict ozone column concentrations, but
Also, as pointed out earlier (Müller and Grooß, 2009), the absolute value of the ozone column average is not correctly calculated by Lu (2009). This is also the case for the ozone averages reported by Lu (2010a). The “October average zonal mean total O3” over Antarctica (60-90 S) in 2006 derived from OMI data should be 211 DU, not 181 DU as stated in the first paragraph of Section 7 of Lu (2010a). Therefore, predictions of future polar total ozone values based on Eqs. 7 and 8 of Lu (2010a) cannot be considered meaningful.Perhaps more tomorrow.