Here is the latest monthly value from the state of the art Climate Reference Network, (CRN) which never seems to make it into NOAA’s monthly and yearly climate reports. But, I produce these maps now monthly since NOAA doesn’t. You can see NOAA’s monthly report here.
Before our alarmist readers get too carried away with the revelation of the CRN network being a bit warmer, you should check the map just below this one.
![crnmap-monthly-avg-temp-f_stations_national_1920x1080_201301[1]](http://wattsupwiththat.files.wordpress.com/2013/02/crnmap-monthly-avg-temp-f_stations_national_1920x1080_2013011.jpg?quality=83)
Click the map to enlarge – The yellow number is from the most recent NOAA SOTC report from the older Cooperative Observer Network while the blue one is from the CRN data that I ingest and calculate regularly now.
Now have a look at this map comparing the old and new networks:
![crnmap-monthly-avg-temp-f_stations_national_1920x1080_201207[1]](http://wattsupwiththat.files.wordpress.com/2013/02/crnmap-monthly-avg-temp-f_stations_national_1920x1080_2012071.jpg?quality=83)
The second map is from July 2012. Notice that the network averages have flipped in relation to one another.
I’ve noted this flip happens every year since 2008 (when the CRN was completed and the year with the first full data set). There’s a physical explanation for this. Do you know what it is? I’ll leave you to figure it out in comments.
I’ll have more on this new CRN resource next week.
The source data for the CRN is here.
The source data for the COOP is here
With the millions in taxpayer money spent to create the new state of the art climate monitoring network, you’d think they would report the data to the public along with the monthly and yearly SOTC reports.
Related articles
- Announcing the first ever CONUS yearly average temperature from the Climate Reference Network (wattsupwiththat.com)
- NOAA SOTC Claim that 2012 Was Warmest La Nina Year is Wrong (wattsupwiththat.com)
Consequence of time of observation and day light savings time ?
Larry
Could the temp differences be due to the fact that the thermometer enclosures in the newer network use forced ventilation?
Sampling period not the same ?!
Zero-order hold noise due to sampling period cause a delta temp dependant on temp slope around that mount ?!
From the August 30th WUWT posting, is the difference an artifact of the way each day is averaged?
CRN averages multiple readings and COOP uses min/max.
Sad But True.
The COOP and ‘happenstance measures’ are a wash, completely unusable.
That was the conclusion to a report of some now 30 years ago and that report was cited recently.
And this conclusion applies to all ‘near surface land born temperatures’ from 1800.
I.e. ‘Temperature’ is not what many, then and Now, think it is !
Sad But True.
Is the difference due to Coop Net. being the average between just two data points, Tmin and Tmax, whereas the CRN averages many data points throughout a 24 hour period. In turn, would the flip between summer and winter be because those two seasons have different temperature curves?
To start with, CRN has 115 sites while COOP has 1218. However, the CRN sites seem to be evenly distributed across the CONUS area, while the COOP sites are clearly concentrated in some areas more than others. COOP may be more influenced by coastal proximity, Great Lakes, and Southern bias.
Hm. At a guess, I’d suppose that the difference is due to the relatively poorer siting of the COOP leading to larger temperature swings, thanks to siting of COOP locations in environments with (effectively) low heat capacities (think concrete vs. grass, unsheltered from wind and sun vs. exposed, etc.) The more poorly-sited locations should respond more dramatically to temperature swings than the well-sited, well-maintained locations–and that would include the grand temperature swings of many months that we call summer and winter.
In winter the COOP network is poorly sited close to very cold external sources causing heat to radiate away from the temperature station thus lowering its reading. In summer the poorly sited COOP stations are located too close to high temperature sources which cause radiation to increase station temperature readings.
UHI-effect.
The “Pine Tree Effect”. The CRN stations are located out in the woods where there are more pine trees which are excellent at absororbing the sun’s rays. The COOP pooly located stations are near larege open areas covered with snow which reflect the sun’s rays.
I’m going to go with something to do with daylight savings time queering the reading times.
Steve Mosher: Lately I’ve noticed you’ve been taking the time to explain yourself in your comments. I enjoy these comments and actually learn something from them. But I have to agree that your “usual drive by crypto-obfuscation-opinions without data” are annoying. Please continue your recent trend of taking the time to explain yourself. I think most of us here prefer being enlightened as opposed to annoyed.
Congress is in session in the winter and in recess during the Summer. Therefore more hot air in Winter vs Summer.
Steven Mosher says:
February 14, 2013 at 5:45 pm
This is an interesting comment from a smart person who has done a lot of work with modern temperature records. I wonder how it extends to paleoclimatology practices such as:
— Splicing a thermometer based temperature construct onto a one largely built with treenometers.
–Combining treenometers, cavenometeters, coralnometers,sedimentary layernometers etc. to create a proxy based temperature record and claiming the average absolute temperature today is clearly warmer now than it has been for 2000 years.
Does reporting “averages” to 4 place accuracy, with measuring devices with 2 place accuracy, make ANY sense?
Max
Gary Hladik says (February 14, 2013 at 5:19 pm): “I’m guessing that the summer/winter COOP/CRN difference is due to sun angle, as Crosspatch suggested, perhaps because some poorly sited COOP stations are shaded by objects (trees, buildings) from the south with a low sun angle but not with a high sun.”
Thinking more about it, sun angle/shading would only account for the lower COOP temps in winter, not the higher ones in summer. So the summer difference could be due to a higher COOP UHI, as the CRN stations are supposed to be all (or nearly all) “rural”.
Summary: The COOP network as a whole has a higher UHI bias at all times than the CRN network and so would read higher in all seasons, except that some poorly sited COOP stations drag down the COOP average in winter because of shading.
Is that even close? I see the magnitude of the winter delta is roughly equal to the summer delta, which seems a bit too coincidental…
A physical reason CRN average > COOP average in winter.<in summer?
Sensor type?
Siting issues would tend to the winter values being greeter for coop.
When are you gonna tell?
I thought that a properly constructed Stevenson screen was supposed to negate the effects of direct sun and shade? My experience of Mason’s Hygrometers was all shipboard though, where they have inbuilt forced ventilation nearly all the time due to the forward motion of the vessel. We used to average the readings from two hygrometers, one on either bridge wing. They were rarely within 1 degree C of each other, which gives some idea of the tolerances involved…
NOAA CRN Temperature sensors are mounted at 10 ft (http://www.ncdc.noaa.gov/crn/sitedescription.html) CO-OP sensors are mounted at 5 ft. Ground surface temperature has a greater diurnal range than air temperature, so a sensor closer to the ground will have great max temps and lower min temps.
CRN shows the wrong kind of degrees?
\sarc if needed. Otherwise credit to my account.
Well, my “official” answer is, “No. I don’t know.”
But I have to make a guess and it’s that in the old system, the readings are taken in the dark in winter and in the sunlight in summer, so the seasonal variation is larger than when you measure frequently.
Max Hugoson asks:
It could in the right circumstances. If you make 10,000 individual measurements each to 2 dp, then provided there is no systematic bias in the measurement errors, their average is known to 4 dp. But you’d need 10,000 measurements to get that level of precision. The average of 1,000 measurements with an error of +/- 0.005 (implied by 2dp) has an error of +/- 0.00015, which is better than 3 dp but less than 4 dp.
It would always be much better if everyone quoted standard errors explicitly.
But there is nothing intrinsically insane about the idea of being able to quote averages of large data sets to much finer resolution than the individual measurements can be made. Errors, provided they are unbiased and independent of each other, grow with the square root of the number of observations. So the more observations you make, the more precisely you know their average.
If you want to report any average temperature, you need to explain what you are averaging. If you simply average the monthly mean temperature for each station, you will get one kind of average. Observing how that type of average changes with time will be meaningless as stations are added, drop out, or become intermittent.
A more useful average attempts to use the output of one or more stations to assign a temperature to everywhere (say every 100 km2) on the surface of the country and then calculate the average surface temperature. Monitoring how the average varies with time will makes sense even if the number of stations reporting changes modestly with time.
One might call the former the average thermometer reading and the latter the average surface temperature.