Thursday, September 20, 2012

Arctic Sea Ice Extent minimum reached

After a couple of days of substantial ice increase, and given the time of the month, I think it is safe to say that the ice extent minimum has been reached. Both IJIS JAXA and NSIDC agree on the date - 16 September. The numbers were:

DateExtent million sq km
IJIS JAXA16 Sept3.489063
NSIDC16 Sept3.36855

IJIS multi-year graph here.

Sunday, September 16, 2012

Javascript rendering of spaghetti plots

My first Javascript exercise used Javascript to enhance visibility of plots with many curves (spaghetti). You could roll the mouse over names in a legend, and in turn the named curves would stand out in black.

I had intended to make more use of that, but somehow that hasn't happened. A minor reason is that the JS code was unnecessarily complicated (being my first).

More spaghetti plots have been appearing at Lucia's, this time re GCM model results, and there was discussion of how to make them more readable. So I thought it was time to scrub up my old code, and this time make the generation of JS an automatic process that others could use.

So I'll give below first the GCM results plots, and then instructions on how to generate it from your own data file.

Saturday, September 15, 2012

August GISS Temp up 0.09°C - ice news

The GISS land/sea monthly anomaly rose from 0.47°C July to 0.56°C in August. GISS has recently been more volatile than other land indices (though similar to satellite), and again this month TempLS was steady. Time series and graphs are shown here

Meanwhile, Arctic ice has been slowly melting. I've added a line on the monitoring page where you can see what minimum will be reached if melting follows the pattern of previous years. The current IJIS JAXA extent is 3,542,000 sq km, which is 749,000 sq km below the previous record minimum in 2007.  The greatest further melting in recent years (2006-) was in 2010; if we follow that pattern it will reach 3,357,000 sq km. IJIS is still melting - NSIDC has shown some refreezing, but that may change again.

Monday, September 10, 2012

August TempLS Global Temp up slightly (0.01°C) from July

The TempLS analysis, based on GHCNV3 land temperatures and the ERSST sea temps, showed a monthly average of 0.48°C for August, up from 0.47 °C in July. After a rapid rise to April this year, TempLS has been steady, with a small downward drift. There are more details at the latest temperature data page.

Below is the graph (lat/lon) of temperature distribution for August 2012. I've also included a count and map of the stations that have reported to this date, and a survey of the degree of error caused by my customary early reporting.

Sunday, September 9, 2012

Cold Confusion

Eli has noted a rather remarkable scientific riff from Mitt Romney:
I do believe in basic science. I believe in participating in space. I believe in analysis of new sources of energy. I believe in laboratories, looking at ways to conduct electricity with -- with cold fusion, if we can come up with it. It was the University of Utah that solved that. We somehow can’t figure out how to duplicate it.

Well, of course Romney doesn't claim to be a scientist. It sounds like he's mixing up cold fusion with high temperature superconductivity. And I guess the last sentence is true.

Anyway, I was curious to track down the source and context. It's from an interview Dec 7 2011 with the Washington Examiner. The transcript and video are here. It's on video part 2 (actually audio only) at about 5 min.

Tuesday, September 4, 2012

Empirical Model - WUWT Style

At WUWT, Girma Orssengo, PhD, has a guest post showing some of the empirical models that he often posts in comments at Climate etc and elsewhere. It shows a parabolic+sinusoid fit to HADCRUT3:

The key plot is the one on the right. It's often been observed that a 60-year (or thereabouts) cycle plus a linear or quadratic does fit in this way. The question is, what does it mean? And in particular, can it be used for prediction?

Girma says that it isn't meant as a basis for physics interpretation. But when challenged about prediction, he said:

" Girma says: September 4, 2012 at 12:53 am

A model is only useful if it allows predicting future behaviour. I see no predictions by the author that could be later falsified by the real outcome.

The model established a pattern as shown in Graph “f”. From this graph, It is easy to predict the climate if the pattern continues => Little warming in the next 15 years."

So prediction does seem to be an aim.

The problem with curve fitting is that behaviour outside the range is determined by the rather arbitrary selection of basis functions. I tried a regression fit in R using the same basis functions, with similar results: