the Air Vent

Because the world needs another opinion

Archive for March, 2009

Measuring the Clouds

Posted by Jeff Id on March 31, 2009

Guest post by Jeff C

—-

Id,

Jeff C has located a possible problem with cloud contamination of the surface dataset. This is an ongoing investigation but there are some apparent differences in result from the most recent NOAA 16 satellite as compared to the rest. This is an important issue as the methods section of Steig’s Antarctic paper cites clouds as the single greatest source of error.

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Hansen’s Dissin’ Freeman Dyson…..

Posted by Jeff Id on March 31, 2009

Dr. Freeman Dyson has created quite a stir. Enough so that even Hansen had to back off from his rhetoric.

Tomorrow’s NY Times Magazine article (The Civil Heretic) on Freeman Dyson includes an unfortunate quote from me that may appear to be disparaging and ad hominem (something about bigger fish to fry). It was a quick response to a reporter* who had been doggedly pursuing me for an interview that I did not want to give. I accept responsibility for the sloppy wording and I will apologize to Freeman, who deserves much respect.

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The Blend…Inator!!!

Posted by Jeff Id on March 31, 2009

I ve been watching Phineus and Ferb cartoons with my 3 year old lately. The villan makes one machine after another with -inator on the end it cracks me up. Actually this post explores the blending of trends across the Antarctic from RegEm processing of he surface station and satellite data. It’s the Bass-o-matic for temp data.

This post uses a modified mapping script courtesy of RomanM which shows the correlation of satellite gridded data relative to a single time series across the antarctic. There are three columns of graphs below comparing surface station data with three varieties of the satellite data. I left all 42 surface stations in just as a reference, only 38 were used in the reconstruction.

1 – The first column is the raw Comiso AVHRR data as presented by Steig09. The data exists from 1982 to 2007.

2 – The second column is from the Steig09 reconstruction data, this data is also post 1982.

3- The third column is also from the reconstruction data, this is a comparison of the surface station data to the pre-1982. The satellite data didn’t exist during this period so it is entirely RegEM.

Remember the shape of the 3 pcs as plotted across the antarctic by CA HERE and the fact that there are only the first two effective PC’s as shown by this plot below.

three-main-pcs2

In these plots below, data with less than 5 values for correlation in the time period was not plotted.

corplots-37

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Reading Between the Clouds

Posted by Jeff Id on March 29, 2009

Jeff C left this comment over on Climate Audit. It touches on a very important subject regarding the current data, the instrument quality. Satellite’s experience harsh environments in space. Temperatures fluxuate by hundreds of degrees, mircrodebris hurtle around at speeds which make bullets look like they’re standing still, there are high radiation levels and consequently the instruments decay over time. During the satellite record of the antarctic there were 5 separate satellites used to collect the data. All of these factors need to be accounted for in understanding the data quality.

This is especially important when trying to nail down a very subtle (less than 1 degree) shift in data that varies by 60 degrees C being measured from an environment (space) that shifts every hour by hundreds of degrees C. Clouds in the Antarctic are known to be both warmer and cooler than ground temps depending on a number of factors. These clouds must be masked out which is an extremely difficult process especially when they can’t be seen at night. It’s no surprise then that clouds are cited by the NSIDC as one of the sources of noise in the surface temperature data.

Well anyway, Jeff took a look at the cloud levels as presented by the NSIDC and check out what he found.

———

Jeff C

I have been reviewing the cloud cover percentages from the UWisc data set. These values can be extracted from the UWisc data set using Steve’s script in the UWisc thread. Change “surft” to “cldtype” to retrieve the cloud type parameter. For the monthly datasets, cloudtype is a value from 0 to 99 that gives the per-cent of time a cell was considered cloud covered during the given month.

I have all the individual values, but calculated some monthly means to give a quick read on how often the continent is cloud covered. I was surprised by the high frequency, but also found some other interesting items that make me question the effectiveness of the cloud detection and masking process.

Here are plots of the continental monthly means (average of all 5509 cells) for the 0200/1400 average, the 0200 alone, and the 1400 alone. I have added the time periods of the various spacecrafts to the plots.

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Satellite Anomaly Video – Know your data pt 3.

Posted by Jeff Id on March 29, 2009

I spent the morning making this video. Click on it to link.

The left side is the raw anomaly from Comiso’s data presented as the original Raw data for Steig O9 the right is the 3 pc data presented as the reconstruction. There are of course some unique differences.

One thing which I noticed from my previous looks at NSIDC AVHRR is that Comiso managed to remove the sea ice contamination from the beach pixels. Not that its a difficult thing for a Jedi.  Another is that the mountain range in the lower left aren’t a great boundary for the weather.  Temperature trends often cross them, an effect which cannot be shown using only 3 pc’s.

movie-screenshot

Updated per TCO request..  I’ve added a picture showing the locaton of the mountains and how trends are separated according to Steig 09.  The trend’s across the boundary have every possibility to be related to the mathematics used rather than the true temperatures of the area.  This isn’t a shot at anyone and may not change any conclusions, it just is what it is.

antarctic-picture-warming

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Mullagain

Posted by Jeff Id on March 29, 2009

This is the second time in two day’s I’ve had to replace a post and frankly I’m not happy. There’s some detail involved in converting the lat and lon to Cartesian that was botched. Again, I’m going to snip myself in the meantime before I lay out a bunch of @#$! and just present the fixed and many times checked plots. Before you pass judgment, what did you do with your Saturday?

Per TCO request and my oversight, the following graphs represent surface station data on the Y axis and the closest Steig AVHRR gridcell on the X axis.

Here are the correlations.

steig-surface-raw-correlations-13


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Statpad’s Unofficial Launch

Posted by Jeff Id on March 28, 2009

RomanM has been playing around with his own blog lately. He’s put up an excellent post which clearly shows how correlations were spread around the antarctic by using 3 pcs. Check out this plot below.

Now I’m a little mischievous by nature so even though this is apparently an ‘unofficial’ under construction post, it is well worth reading. Let’s give Roman a little encouragement and leave some comments. After all it’s the comments that fuel blogs.

Click here for STATPAD.

http://statpad.files.wordpress.com/2009/03/avhrrpen1.jpg?w=538&h=537

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Raven’s Reasoning

Posted by Jeff Id on March 28, 2009

I made another mistake again today. It’s really not my day, the Red Wings lost too. I went over to Tamino’s closed mind blog where his mindless followers swarm any dissent. Yeah, I know I never learn. Tammie simply amputates any views his angry mind can’t handle. He really is an unusually angry person. I’ve tried to discuss things with Tamino and his followers simply pile on, insult and have no idea you’re not allowed to respond.

Today my eyes caught a discussion between Ravin and Tammie …… After reading, I realized that I actually have a blog and an audience as well. So instead of getting my comments clipped, I’ll just post it here and let anyone who feels the need, make comments.

Raven // January 31, 2008 at 6:03 am

Interesting.

It has been my position that the temps in 2015 would have to be at least 0.2 degC higher in 2015 to validate the AGW position. This was a crude calculation based on the CO2 sensitivity ranges presented in the IPCC report.

Your graphs come up with that same spread for different reasons.

That said, I don’t trust the GISS and HadCRUT datasets for the same reason I would not trust the unaudited financial statements produced by the Enron. I realize the satellite measurements have their own issues but there are two competing groups using the same dataset which helps ensure that self-serving data manipulation is kept to a minimum.

Would you take the bet on the average of UAH and RSS or is it limited to the GISS/HadCRUT?

Instead of betting money would you be willing to publicly acknowledge that AGW alarmists got the science wrong if you lost? Would you be willing to publicly apologize to skeptics who you have denigrated?

If not what would it take for you to do that?

The way I see it bets for money are a red herring since most people are prudent and would never bet more than they could afford to lose even if they were 95% sure about the outcome. Instead of fooling around with bets for money you should state what it will take to change your mind.

[Response: Your implication that GISS or HadCRU is guilty of "self-serving data manipulation" is mean-spirited, offensive, and unsupported by any evidence. Unless you can offer EVIDENCE with documentation to back it up, don't repeat it here.

Your questions make me wonder whether you actually read the post. What part of "I’ll also emphasize that I’m not interested in betting money on it" is unclear? What part of "If, however many years from now, the no-more-warming side wins the bet, and no unequivocal caveats are identified, then I’ll admit that our understanding of global climate is insufficient and that we can’t rely on the prognostications of the climate science community" is unclear?

Shame on you.]

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Comiso’s Data

Posted by Jeff Id on March 28, 2009

Sometimes there are surprises in reconstructing papers. I can’t claim to have spent the time like this before but as I do now I’m learning. Our friend the Laymen asked for a plot of the new data as compared to surface station data. It’s rather impressive.  The data in this post is from Steig O9 raw data compared with the closest gridcell to the surface station..

Comiso is an Antarctic Jedi. I don’t know how he did it but the data he produced is of fantastic quality. Check out these plots. There’s no facetiousness here, this is just plain impressive. I have to know how he did it.

steigamundsen_scott1


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Posted in Uncategorized | 9 Comments »

Auto-matic Correlation

Posted by Jeff Id on March 27, 2009

This post has an error.  The calculation inadvertently used temperature rather than anomaly.

Thanks to Steve McIntyre at Climate Audit and comments from Hu McCulloch at Climate Audit for quickly spotting this error and bringing it to our attention.  I think this points out pretty well that accusations of cherry picking or playing favorites on Climate Audit aren’t reasonable.  Problems get chopped up and spit out regardless of the source or meaning.

The two Jeffs


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Posted in Uncategorized | 27 Comments »

Preliminary PCA of Steig Data

Posted by Jeff Id on March 27, 2009

I moved my previous post done yesterday back to the top of the page.

—-

Today I received the data from Dr. Steig on the Antarctic paper. He sent a polite and very short response to my email and activated the file, no references to matlab classes. I don’t think he’ll mind because it is a short email but if he requests I’ll remove it.

Dr. Steig,

A link was provided on your homepage for the satellite AVHRR data. The filename is cloudmaskedAVHRR.txt.

Currently it appears to be unintentionally set for password permission only to access. I am interested in continuing analysis of this data through RegEM and comparison to the NSIDC AVHRR dataset. Can you please reset permissions for download?

Jeff

Sorry about that, permissions set wrong accidentally. Now accessible.

Eric

Thanks much.

Well everyone at CA is looking closely at it now. I’ve done a PCA analysis to compare this data to the 3 pcs provided in the reconstruction, they are close but not a perfect match. This is a quote from the paper in methods.

The first two principal components of TIR alone explain
.50% of the monthly and annual temperature variabilities4. Monthly anomalies
from microwave data (not affected by clouds) yield virtually identical results.

The statement about 50% seemed pretty questionable to myself and others. This next graph represents the eigenvalues weights.

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NSIDC Sat Data PCA

Posted by Jeff Id on March 26, 2009

I thought about titling it NSIDC AVHRR PCA just for fun. I ‘ve done a short PC analysis of the antarctic data to see if I could replicate Steig’s 3 pc’s. It didn’t work out very well but it returned some interesting results. I had to post this now because we just got the real data from Eric Steig and will be using that next and will have something to compare it to.

Before I get started, credit for the code goes to about a dozen people, Jeff C, SteveM, Roman, Ryan and myself. I may have added someone or left someone off inadvertently but it has a pile of people involved.

First here is a plot of the first 100 eigenvalues.

avhrr-eigenvalues

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Sat vs Ground Difference Plots

Posted by Jeff Id on March 26, 2009

Just a short post where I plotted the difference between the surface station data and sat data as per a request by Kenneth Fritsch. The main thing I notice is the noise level in these graphs is large enough to dominate any minor ‘real’ slope signal. These plots again use the NSIDC raw data and do not use Steig’s unavailable data.

This is a continuation of my other post Know Your Data and it uses the 1400 ‘day’ version of the data.

diffamundsen_scott

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Contact the Owner

Posted by Jeff Id on March 25, 2009

Below is one of my many requests for data left on RC (after multiple other attempts from other avenues). RC now has edited the link, apparently they weren’t happy with the hundreds of travelers to my blog that went on for weeks.

jeff Id Says:
4 February 2009 at 11:21 PM

A link to my recent post requesting again that code be released.
[edit]
I believe your reconstruction is robust. Let me see the detail so I can agree in public.

[Response: What is there about the sentence, “The code, all of it, exactly as we used it, is right here,” that you don’t understand? Or are you asking for a step-by-step guide to Matlab? If so, you’re certainly welcome to enroll in one of my classes at the University of Washington.–eric]

I told TCO a couple of days ago about my habit of bolding the crazy stuff.

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Bad Scientist of the Week

Posted by Jeff Id on March 25, 2009

Andrew Weaver wrote a piece for the Vancouver Sun which I would describe as typical doublespeak for a politician but Andrew Weaver holds himself to be a scientist. Andrew’s won the newly invented yet highly coveted and sought after ‘bad scientist of the week’ award.

Andrew Weaver is a lead author for the Nobel Prize-winning Intergovernmental Panel on Climate Change. He is also a guest blogger for http://www.zerocarboncanada.ca, where there is a lively discussion on these issues. He is based at the University of Victoria.

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