Sunday, April 26, 2015

GWPF inquiring into temperature adjustments

Well, this is an interesting one. GWPF has announced an inquiry into temperature adjustment practices. It is being boosted by Booker at the Telegraph ("Top scientists start to examine fiddled global warming figures") which is a bad dent in its credibility. However, it has a reasonably qualified panel, so it may be interesting to see what they develop. They have asked for submissions by June 30, so I might try to come up with something. But the remit sounds like they have been advised by Paul Homewood. For now, I'll just review that:

Are there aspects of surface temperature measurement procedures that potentially impair data quality or introduce bias and need to be critically re-examined?

Are they talking about current practice? Or that of years past? Are they going to recommend how it should have been done back then?

How widespread is the practice of adjusting original temperature records? What fraction of modern temperature data, as presented by CRU/GISS/NOAA/BEST, are actual original measurements, and what fraction are subject to adjustments?

This is framed Steven Goddard-style. How widespread is the practice of doing arithmetic? People use records to calculate spatial averages etc, and may well wish to adjust for that purpose. As they should. Is detrending, say, an adjustment? Or calculating an anomaly?

 CRU/GISS/NOAA/BEST do present data. NOAA explicitly offers unadjusted and adjusted data. GHCN Daily is largely an unadjusted copy of what the national Mets have, and GHCN Monthly unadjusted is a straight average of that (for long-record stations). But the primary business of CRU/GISS/NOAA/BEST is the calculation of spatial indices. That is basically a spatial integration, and requires manipulation. They have to calculate estimates of what actually happened in sub-regions, and they publish that.

Are warming and cooling adjustments equally prevalent?

Goddard again. No. Why should they be? Adjustments are for the repair of bias. If the identified bias is down or up, the repair will rightly have the opposite effect. TOBS, in the US, has a clearly cooling bias. The reasons are well established in terms of observing practices of the past, and so correction is clearly warming.

Are there any regions of the world where modifications appear to account for most or all of the apparent warming of recent decades?

This is straight Homewood. There may be some. The inference is that there was a cooling bias that masked all of the warming. But it isn't common. If it helps them, the broad regional breakdown is here.

Are the adjustment procedures clearly documented, objective, reproducible and scientifically defensible? How much statistical uncertainty is introduced with each step in homogeneity adjustments and smoothing?

Well, it will be interesting if naysayers finally bring themselves to read the papers of Menne and Williams etc. But agenda may intrude. Statistical uncertainty of what, I wonder? Anyway, I'll probably send in a submission. I've been working out how to convert the html of blog posts to pdf. We'll see.

ps ATTP

Update. I noted something amusing. Booker's articles (based on Homewood) have clearly been influential in setting up the inquiry, and at GWPF, Peiser has prominently featured Booker's announcement in the Tele. But he modified the headline to
"Top Scientists Start To Examine Adjusted Global Warming Figures"
As I noted above, Booker's headline is actually:
"Top Scientists Start To Examine Fiddled Global Warming Figures"

I guess GWPF likes to sound a little more objective.

Update again. Here at Homewood's blog is Booker celebrating their achievement in staging the inquiry
"It was entirely prompted by the two articles I wrote in the Sunday Telegraph on 24n January and 7 February, which as I made clear at the time were directly inspired by your own spectacular work on South America and the Arctic."

Wednesday, April 15, 2015

March GISS up 0.06°C

As several commenters have noted, GISS is up by 0.06°C, from 0.78 to 0.84. I had expected a small rise; David Appell was close. That's one of the hottest months on record, and makes 2015 a very warm year so far. TempLS rose by a smaller amount, and the troposphere indices declined.

Sunday, April 12, 2015

Global surface TempLS up slightly in March

This post is a bit late this month. I've been holding it waiting for GHCN results from China and Canada. China has finally come in - still no Canada. Anyway, the TempLS mesh index was 0.717°C, slightly up from Feb 0.698.

One reason for delay was that I had predicted a slight rise, and I didn't want that result to be unsettled. The margin was very fine, but China raised it somewhat. It's still possible that Canada could bring it down.

As mentioned in earlier posts, although temperatures are not changing rapidly, they are very warm. The first three months of 2015 were each warmer than any month of 2014 (thanks, MMM). The NCEP/NCAR index for April has a sudden dip.

The greatest warmth was in the North - Siberia and Canada, extending into N Europe and W Canada. Coldest was again East N America, and also a patch in N Atlantic. Troposphere measures (UAH and RSS) were down slightly, but Roy Spencer noted a similar pattern. Surface coldness was less extreme in E N America.

Tuesday, April 7, 2015

Dynamic trend viewer

This was intended as a graphic facility for my post on GHCN data. However, alas, there was mission creep, and a dynamic trend viewer, in the style of the trend viewer page, emerged. It's "dynamic" because it is all in Javascript. I don't have to pre-calculate and store images. This is fine for annual data - calc time might be a problem for monthly. But the style of access also gives a rapid response which is fun to play with.

As with the trend page, I show a graph of the time series. Data options supplied are the usual collection of global temperatures, but you can also supply your own. And there is a color triangle, in which each dot (square) is a start/end year combination, with the color showing the corresponding trend. With the trend page, you could click on that to change the range; there were also controls in the graph. Now you just run the mouse over the triangle, and the red trend line on the plot moves dynamically, and the information is echoed top right. The triangle is oriented so the NE corner is starting ending 2014, and SE is the whole range. x axis is start year, y-axis is end year. The info in the upper triangle will tell you where you are.

I haven't given a color key, because you get an instant print response - basically, rainbow with red for warming. To change data set, select from the menu and then press the "Enter data" button. To enter your own, just convert it to a comma separated one-line list, and paste into the text window, and then click "Enter Data". The button enters the last thing you changed (text window or selector). If you enter data, it is attached to the choice "User Data" in the data menu. Initially, I have put a sinusoid there, which you can select. It shows graphically how the trend works as a derivative.

Wednesday, April 1, 2015

Early note on March 2015 global

Most of the NCEP data for March global surface temperature is in, and despite some cooling at the end, it still looks to be a little warmer than February. Probably less than May 2014, but higher than any other month in 2014 (or 2015). I'd expect this to be reflected in surface temps.

I've fixed a bug where in the daily NCEP table, dates were written one day ahead (on Australian time). Dates on the maps were correct.

Thursday, March 26, 2015

GHCN Monthly data portal

I am planning to add station data to the GHCN V3 monthly portal. Not monthly data which would be cumbersome, but annual average. This is useful for plotting and trends.

There is a trial below. Each link leads to the NOAA GHCN station summary, as before, but the radio button brings up a page with a table of the annual averages, along with a brief metadata and a map (the station is in the middle). There is a table for unadjusted data, and below for adjusted. Both are then repeated in CVS format, for import into Excel. The table of links is searchable (Ctrl-F), and can take a while to load. I'll probably add a graphing and trend calculation capability.

Friday, March 20, 2015

Central Australian warming

I've been arguing again, at Climate Etc. Blogger Euan Mearns has a guest post in which he claims to demonstrate that stations within 1000km of Alice Springs show no warming.

I'll post about it here, because it illustrates the averaging fallacies I've been writing about regarding Steven Goddard and colleagues (also here). And also because "Alice Springs" is one of those words naysayers sometimes throw at you as if no further explanation is required (like Reykjavik). People who do that generally don't know what they are talking about, but I'm curious, since I've been there.

There are actually two issues - the familiar time series of averages of a varying set of stations, and anomalies not using a common time base. I'll discuss both.