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Wetbulb Temperature

November 7, 2010 | Steven Mosher

This google map display is just one of 230 GHCN stations that is located in the water. After finding  instances of this phenomena over and over, it seemed an easy thing to find and analyze all such cases in GHCN. The issue matters for a two reasons: In my temperature analysis ... [Read more...]

CrossValidated launched!

November 4, 2010 | Rob J Hyndman

The CrossValidated Q&A site is now out of beta and the new design and site name is live. New design The new design looks great, thanks to Jin Yang, our designer-in-residence. Note the normal density icon for accepted answers and the site icon depicting a 5-fold cross-validation (light green ... [Read more...]

Errors in Ghcn Inventories

October 30, 2010 | Steven Mosher

In the debate over the accuracy of the global temperature nothing is more evident than errors in the location data for stations in the GHCN inventory. That inventory is the primary source for all the temperature series. One question is “do these mistakes make a difference?” If one believes as ...
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A question from the R list

October 30, 2010 | Steven Mosher

I am currently working on rectifying the GHCN station list to improve the location information. Its the kind of database work that is mind numbingly tedious and a PITA in R. not because R lacks capabilities, its just tough and not very sexy to matching and fuzzy matching and greping ... [Read more...]

Different results from different software

October 26, 2010 | Rob J Hyndman

I’ve had a few questions on this topic lately. Here is an email received today: I use Eviews to estimate time series, but I have been checking out R recently, and your Forecast package. I cannot understand why 2 similar equations in Eviews and R are giving different estimated output. ... [Read more...]

How to avoid annoying a referee

October 22, 2010 | Rob J Hyndman

It’s not a good idea to annoy the referees of your paper. They make recommendations to the editor about your work and it is best to keep them happy. There is an interesting discussion on stats.stackexchange.com on this subject. This inspired my own list below. Explain what ... [Read more...]

What’s that 5km from the station “location”

October 21, 2010 | Steven Mosher

In our last installment we looked at stations which were pitch black. The case I examined, Middlesboro Kentucky illustrated 1. The station location data used by Hansen2010 has inaccuracies. 2. While the purported station location was pitch dark, nearby within a couple 1/100ths of a degree there were urban lights. What this ...
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Happy World Statistics Day!

October 19, 2010 | Rob J Hyndman

The United Nations has declared today “World Statistics Day”. I’ve no idea what that means, or why we need a WSD. Perhaps it is because the date is 20.10.2010 (except in North America where it is 10.20.2010). But then, what happens from 2013 to 2099? And do we just forget the whole idea ... [Read more...]

Middlesboro Kentucky: Pitch Black?

October 19, 2010 | Steven Mosher

In his august draft of Hansen2010, Dr. Hansen makes the following claim: “We present evidence here that the urban warming has little effect on our standard global temperature analysis.  However, in the Appendix we carry out an even more rigorous test. We show there that there are a sufficient number ...
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More Graphics with Google earth

October 18, 2010 | Steven Mosher

Dr. Paul, R graphics guru, blessed us with his rendition of transparent contour maps drawn on a google earth image: Cool stuff. I’ll be taking his code and turning it into a function and sharing it back: here is the picture his code creates: That is just plain slick.  ...
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Giss Nightlights Replicated

October 18, 2010 | Steven Mosher

UPDATE: holy open source to the rescue. I posted a question yesterday on a idea peter had. Transaprency for overlaying light maps onto google maps. reminds me of the old Quake days. Well, I know John Carmack, John is an old friend of mine, but I’m no John Carmack. ...
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Boundary conditions Dominate

October 16, 2010 | Steven Mosher

In part 1 and part 2 we went over the background of nightlights and the fundamental problem: Station inventory data had errors in it: In Hansen 2010, Hansen writes: “ Station location in the meteorological data records is provided with a resolution of 0.01 degrees of latitude and longitude, corresponding to a distance of about 1 [...]
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Accuracy in Inventories and Nightlights Part II

October 16, 2010 | Steven Mosher

In part 1 we discussed UHI in a general way and introduced NASA’s use of nightlights to identify Rural, periurban and Urban stations. Very simply, the latitude and longitude data in the station inventory is used to look up at radiance value in the nightlights file. If that value is  10 ...
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Nightlights: First Principles

October 15, 2010 | Steven Mosher

With the publication of Hansen2010 forthcoming it is critical to examine the subject afresh. The global temperature index product from NASA is known as GISSTEMP .GISSTEMP, like the temperature index from Hadley/CRU and NCDC attempts to estimate the average temperature of the globe using historical data archived in the ...
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Kuwait Airport

October 14, 2010 | Steven Mosher

  Kuwait International airport. Giss has it as nightlights =0, so do I. By looking at comparisons of nightlights with the station centered and a static google map with the station centered, there are mismatches between GISS and Me and between Nightlights and the  world. Subtle shift here and there. Annoying. Also, ...
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Nightlights, Contours, and Rgooglemap

October 14, 2010 | Steven Mosher

I am continuing the investigation of nightlights using some additional packages from Cran. Here we add Rgooglemaps to the mix. Rgooglemaps is a neat tool that gives you a simple ( needs better docs) interface to the static map server. Perhaps, I’ll modify the code to my likeing, so For ...
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Animated plots in R and LaTeX

October 12, 2010 | Rob J Hyndman

I like to use animated plots in my talks on functional time series, partly because it is the only way to really see what is going on with changes in the shapes of curves over time, and also because audiences love them! Here is how it is done. For LaTeX, ...
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