Sunday, January 30, 2011

Lisbon Meeting

My last post said that I would be away - the main object of my travel was to attend the Lisbon Workshop on Reconciliation in the Climate Change Debate. For an excellent summary of the meeting, and its background and purposes, I recommend Judith Curry's two threads (Part I and Part II ). The discussion is interesting too - other participants chime in.

WUWT also has several threads (here too) and has posted the organisers' statement of purpose. Other atttenders have blogged - Tallbloke, Steven Goddard.

I won't at this stage try to add to the facts of what Judith has said. My assessment was similar too. I was interested in Jerome Ravetz' ideas, and impressed by his guidance of the meeting. But I don't have much to say about postnormal science, which I regard as being about society rather than science.

I am very glad I attended the meeting, to hear and meet the participants. I think an agreed outcome was always unlikely, so I was not disappointed there.

I will be travelling for another few days, so apologies in advance if my responses are sometimes delayed.

Saturday, January 22, 2011

A JS gadget for viewing temperature trends.

In my previous post I showed a map of all possible trends calculated over sub-time intervals of a period, with a mechanism for selecting different datasets and periods. Since there seem to be ongoing interest in viewing trends, I thought a useful Javascript gadget could be developed from that.

Now when you select a dataset/time combination, a corresponding time series plot is displayed, with two colored balls representing the start and end of each trend period. The numerical data are displayed on the right. There are several ways of controlling the horizontal position of the balls:

  • You can click on the colored triangle. Each position represents a start/end combination, so the balls will move to the endpoints of the fitted regression line, and the slope and locations will appear on the right. It's a realisation of the color on the plot, and should correspond.
  • You can move the balls by clicking on the red or blue bars on the graph.
  • You can nudge, for fine control, using the <<<<>>>> device of the appropriate color. The outside symbols move the ball of that color by 8 months, the next by 4 and the innermost by 1.

Thursday, January 20, 2011

Hadcrut is in - final temperature summary for 2010

Hadcrut reported a 0.251°C mean NH/SH anomaly for December, down from 0.455°C in Nov. As expected, that leaves 2010 well behind 1998 in Hadcrut's record (about 0.1°C less).

So in summary, the indices that had 1998 as hottest (Hadcrut, UAH, MSU) keep it there (UAH was close). Those that had 2005 as hottest (GISS, NOAA) say 2010 was about the same.

I guess I'll run a tracking plot for 2010, but won't start until a few months into the year. I normally update it on this post, but since it's the final for 2010, I'll show it below:

Tuesday, January 18, 2011

On "Mannian" Smoothing

A recent thread at Climate Audit revisited the topic of "Mannian" smoothing. There's a long history here - here, for example, is a thread to which this seems to be a sequel.

The "Mannian" smoothing to which they refer is described, under the name of Minimum Roughness Criterion, by Mann GRL04 (2004), with a follow-up GRL08.

There was much more discussion of the general idea of Mannian smoothing in some threads on its use by Rahmstorf; at CA: the-secret-of-the-rahmstorf-non-linear-trend
and rahmstorf-et-al-reject-ipcc-procedure, and at Lucia's: more-fishy-how-doesdid-mann-guess-future-data-to-test-projections

In this post I'll try to describe what "Mannian" smoothing does, and why, and how it compares with other methods in the statistical literature.

Thursday, January 13, 2011

GISS shows 2010 as record hot for land/ocean - NOAA declares tie with 2005.

The GISS index for December is out, and while at 0.4C the anomaly is much less than November, it was still just enough to beat 2005. I have updated the tracking plot.

The NOAA also say that 2010 tied with 2005 as hottest year, but don't give the actual anomalies. It isn't in their usual data file, so I can't plot it.

Monday, January 3, 2011

RSS posts December average - 2010 lagged 1998.

RSS posted its December average, and confirmed what had been expected for 2010 - short of the record average in 1998, but still second hottest.  I've updated the tracking plot.

GISS looks likely to report 2010 as the hottest year recorded. NOAA is less clearcut, but still quite likely. The other indices are likely to maintain 1998 as hottest.

I'll be mostly offline for a few days - back at the weekend.