Saturday, March 1, 2014
The 2005 paper was a major resource for Congressman Barton's 2006 inquisition of Mann. One of its featured criticisms was the Gaspe dataset, number 53, and in particular the fact that Mann had padded some missing data from 1400 to 1403 with the 1404 value. And Barton directed Mann et al to explain.
One thing not often now mentioned is that in that paper, M&M actually did what many other critics should have done. They repeated the calculation with their criticism made good, to see what effect it had. This was in their Figure 1. They showed the effect of marking those four Gaspe years as missing, and then the effect of using a centered mean rather than Mann's famous calibration mean. They got a surprisingly large difference, which has been much cited in recent days. This post reports on my investigation of that surprise.
Barton got statistician Wegman to report, and his report was heavily based on the M&M 2005 papers. He said of this
"In MBH98, the first four years of both of these series were extrapolated. The extrapolation has the effect of depressing early 15th century results, and was not disclosed by Mann et al. until a later paper, "
This depressing effect was based on the M&M calculation reported in their Fig 1.
I'll show that the effect of padding those four years was limited to just those four years, and is minor. The effect Wegman describes was due to a coding rule in which M&M in effect removed the effect of Gaspe not just the four years in question, but all years from 1400-1450.
I have previously criticized the use Wegman made of the M&M 2005 GRL code for supposedly showing how noise could generate hockey sticks. There there was a clearly deliberate selection of the top 100, ordered by "hockey stick index", from which the displayed samples were chosen. In the case described here, there is no indication that the amplification of the effect was deliberate. In fact, M&M say they are following a policy of Mann's. However, the effect as presented is misleading, in that the change shown is due to the application of a rule rather than the actual effect of the padding.
Tuesday, February 25, 2014
I have been collecting links for various documents associated particularly with the current libel case of Mann vs CEI/NRO/Steyn. I've been arguing about that on the usual blogs (Lucia,CA,WUWT). I don't want to canvass the arguments here, but just to collect links to relevant documents. For case docs, I've tried to source the very good DC Slapp Law site linked above, partly because its pdf's are selectable.
So here is a table of links. I'll try to add to them over time.
Update. I searched for and copied the case index as at 25 Feb from the SC site. That copy is also linked (top line). Then I stripped down and numbered the calendar, which is in a frame at the bottom. I've shown the corresponding numbers in the links, where they correspond to an event in the calendar. If you click on them, the list in the lower frame will move to show the corresponding numbered item. That gives more info than my brief and informal tags.
Monday, February 17, 2014
Thursday, February 13, 2014
TempLS showed a small rise in January, from 0.48°C to 0,52°C. The satellite TLT from UAH also showed a rise
Update: I'm also keeping the GHCN/ERSST stations worldview updated. It gives a more comprehensive view of temperatures in Jan and before.
Thursday, January 23, 2014
Tennis fans everywhere will know that we had a pretty torrid heat wave last week, the first week of the Australian Open. It wasn't our hottest, but it went for four days. In Melbourne max temperatures were were 42.8,41.7, 43.9 and 43.9°C, or, if you prefer,109, 107, 111, 111°F. This forecast from the BoM explains what was happening; it happened as predicted, a bit warmer at the end. MikeH in comments noted this more complete report from B0M.
There's the usual argument about AGW. WUWT doesn't think so. In fact, they won't much concede that it was hot, and say it happens all the time here. So I thought I'd review in this post our summer temperature history, and also refute some notions that it's all happened before but been hushed up by "adjustments".
Monkey Mia, WA, From ABC
In my post on TempLS for December, I noted that it fell by 0.17°C from November, almost exactly cancelling the previous month's rise. GISS followed almost exactly the same sequence, down from 0.78°C to 0.6°C, having been 0.61°C in October.
Monday, January 20, 2014
With Moygl, you can draw on the Earth surface:
- POINTS - dots of various size and color
- LINES - a group of individual line segments
- TRIANGLES - each individually specified. Normally these will be filled with shading
- LINE_STRIP - a long list of vertices which will be connected in sequence (can be broken with NaN).
- LINE_LOOP, TRIANGLE_STRIP and TRIANGLE_FAN