Comments on: Adjusting Pristine Data

By: Jim Rogers

Jim Rogers — Sun, 22 Mar 2009 17:19:56 +0000

We all know that the average of Max/min is not a good indicator of average daily temperature, showing a warmer daily mean in the winter and a lower daily mean in the summer than compared to hourly or 6 hour avg. (temperature stays lower for most of the day in winter with a max peak and vice versa). Why not run the analysis using only max and min daily temperatures? This would remove error introduced by different month lengths for example. The reason we use to use the means was the lack of computing capability. I use this for some environmental assessment analysis with Kugluktuk/Coppermine data (1932-2006). The trend of max temps rose more quickly than min in that case but still close to the 0.3 C/decade. I suggest ignoring the daily data fills, which appeared bias. Automatic remote data collection was visible.

By: gopalan

gopalan — Fri, 26 Sep 2008 06:43:35 +0000

W F Lenihan:
September 24th, 2008 at 9:48 am

Can someone explain why weather stations don’t have both Celsius and Fahrenheit thermometers to avoid errors from conversion and reconversion of temperatures?

Most reasonable doubt. Men will do the rational thing, but only after exploring all other possibilities!

By: Geoff Sherrington

Geoff Sherrington — Fri, 26 Sep 2008 06:12:57 +0000

Re: BarryW (#13), TOBS again. The tutorial appears to be wrong because when the thermometers are read, they are RESET to the present temperature. Using the example given, there is no mention of the time of day that they were read and reset. But, if the day 1 minimum of -5.6 at 8 am was read and reset at 11 am on day 1 (to pluck a time from the air), then the -5.6 figure was recorded as a correct min and then erased, to start afresh with another value (-0.6). It is -0.6, not -5.6, that carried over towards day 2. If you wish to argue that a reset at 8 am on day 1 was done, yes, it would be there on day 2 at 8 am when the actual min was -3.3. But, the very act of resetting at 8 am would ensure that the max from day 1 was correct and more than likely the max on day 2 was also correct if resetting was also at 8 am on day 2 (on the basis that for each day the max happens after 8 am). The argument in the example is special pleading, including a case where the resetting was done at a daily extreme. Leaving the data alone could well be preferable to referencing to midnight readings by maths infilling, because the thermometers were typically NOT reset at midnight. Midnight is an artificial construct able to introduce errors of its own.

By: HMcCard

HMcCard — Thu, 25 Sep 2008 22:25:54 +0000

John Goetz,

(I tried to post this cmment on Anthony’s website but it didn’t go through for some reason; I’ll try submitting it here.)

I’m sure that you know that the daily temperature data from the Mohonk Lake surface station can be found for the interval 05/1948 through 12/2005 at

http://cdiac.ornl.gov/cgi-bin/broker?_PROGRAM=prog.climsite.sas&_SERVICE=default&id=305426

I selected a random sample of ten completed B91 Forms for Mohonk Lake from the site that you referenced

http://www7.ncdc.noaa.gov/IPS/coop/coop.html?_page=2&state=NY&foreign=false&selectedCoopId=305426&_target3=Next+%3E

and verified that the values for TMAX(F) and TMIN(F), with one exception, were identical. The exception which occurred on 07/12/1956 is an obvious transcription error; the value (67°F) listed in the “At OBSN” column was recorded for TMIN(F) instead of the correct value (64°F). In addition to TMAX(F) and TMIN(F), the USHCN site also lists TAVE(F) which equals [TMAX(F) + TMIN(F)]/2 rounded to the next higher integer when either TMAX(F) or TMIN(F) is an odd integer. Therefore, I believe the data archived at the site that I referenced is the “RAW” daily temperature data for station 305426.

So far, so good …

I then calculated the monthly averages for TAVE(F), TMAX(F) and TMIN(F), for the interval 05/1948 through 12/1959 and compared the results with the corresponding monthly values that I downloaded from

http://cdiac.ornl.gov/cgi-bin/broker?_PROGRAM=prog.climsite_monthly.sas&_SERVICE=default&id=305426

How did they compare? Not so good!!

The average differences for the 139 month interval are (s.d. shown in parentheses):

RAW TAVE(F) – HCN TAVE(F) = 1.39°F (0.43°F)
RAW TMAX(F) – HCN TMAX(F) = 1.43°F (0.62°F)
RAW TMIN(F) – HCN TMIN(F) = 0.83°F (1.17°F)

What adjustments do you think were made by NCDC that caused these differences?

I may add to this post after I complete my examination of the 1948:2005 RAW data set.

Reply: Anthony’s spam bucket tends to grab stuff with a high link-to-text ratio. I think your post was above whatever that limit is. It looks like one of the moderators did find it and let it get through.

As for what you are seeing, I suspect it is homogenization, TOBS, and FILNET differences.

By: MarkB

MarkB — Thu, 25 Sep 2008 20:40:56 +0000

Oops! The link above still works.

By: MarkB

MarkB — Thu, 25 Sep 2008 20:39:29 +0000

I grew up in the Jamaica Plain section of Boston, USA, in the 1960s. As far back as the 1700s, people skated on Jamaica Pond, a 70 acre, 50 feet deep kettle pond. in the 1800s, there was an ice-cutting business taking ice from Jamaica Pond and other local ponds and lakes that shipped ice as far as Asia. The ice houses on the pond could hold 30,000 tons of ice at a time.

As late as the 1930s, my parents skated on the pond in the winter. By the time I was growing up in the ’60s, the pond was closed to skating. Many years since, the pond fails to freeze over and close up open water. When they were harvesting ice, they liked to get at least 12 inches before they cut. The difference is dramatic, and tells me – without yearly data – that the Boston area is warmer now than in the years from the mid-late 1700s and the 1930s. I don’t know the difference, but it must be significant to generate – or not – 12 inches of ice on a pond that size.

That said, the warming observed tells me nothing about the cause of the warming. There has definitely been a warming trend in the Boston area, but I have no idea why. Correlation, as they told me in statistics class, is not causation. No ifs, ands or buts.

By: GTFrank

GTFrank — Thu, 25 Sep 2008 16:41:35 +0000

#1, #16

Any idea where Mr. Depalma got the information that this site showed a 2.7 degree increase in temp?

Benjamin I Cook’s paper is here.

http://www.ldeo.columbia.edu/~bc9z/Publications_files/2007_cook.pdf

By: Lucy Skywalker

Lucy Skywalker — Thu, 25 Sep 2008 10:20:30 +0000

I got the impression that the weather station pictures that littered one episode of the BBC Iain Stewart series, were taken from Anthony Watts’ superb records. He said somewhere earlier he’d been contacted by the BBC. If so, this would be surely another misrepresentation a lot bigger than Wunsch’s complaints re Swindle.

By: Follow the Money

Follow the Money — Wed, 24 Sep 2008 23:38:51 +0000

Re: compguy77 (#1),

Any idea where Mr. Depalma got the information that this site showed a 2.7 degree increase in temp?

These stories are not the product of traditional investigative journalism, but packaged to media sources, the reporter doing little leg work. Often an article will give a clue to its source. Environmental Defense Fund is mentioned, a major player in carbon offsets and cap and trade. Perhaps an EDF publicist contacted the Thomas Friedman at the Times or other “opinion shaper” there, perhaps the major public relations firm managing this show matched the EDF to the reporter. IOW, this reporter did not find this information on the streets of New York City.

Why did they plant the article? It is a reaction to growing knowledge amongst the plebes that the temp records are problematic. This sense is heightened via CA, Watts’ site, and so. This article serves as holy writ to counter such questions and provide an artefact of information in the holy source, the NYT. “But the New York Times said it doesn’t matter. “But the New York Times said…” It is a planted talking point in a source still considered the “last word” in American journalism.

The recent BBC program served a similar duty, but with a broader ambit. It was not progressive but reactive, reacting to key bones of contention bubbling through the public, esp. the British public whose awareness of the issues coincident with the increases in their taxes. It’s intention was to stifle, ridicule, and reaffirm.

By: R DeWitt

R DeWitt — Wed, 24 Sep 2008 22:46:39 +0000

I think you would avoid some confusion in your graph if you used something other than a minus sign to separate the location “Monock Lake” from the equation representing how the difference was computed. It took me a while to understand how I and Lune were misinterpreting the graph.

Reply: Yeah, I know. Bad habit. I should have used a colon.