Following some discussions here in Civics, which apparently is where all climate change related discussion take place on this forum, Mountain Man, and others, have insisted that the GHCN tampered with the data, adjusting and "faking it", in various ways.
This has been a claim thrown around a lot in various articles that cast doubt on whether the science of Global Warming is driven by science or political bias. Typically it is done by taking a graph of the "raw" temperature and subtracting ti from the "adjusted" temperature, and showing that the new adjusted reconstruction tends to make past temperatures colder and newer temperatures warmer.
This has led to suspicion that the various climate groups who have done these temperature reconstructions have their thumb on the scale. Biasing it towards higher temperatures.
I've countered that the adjustments were well founded. They are there to remove bias introduced by a shift of observation time, to changes of instruments, and even the urban heat island or urban cold island effects, and done with good reason. And that the raw data, at any rate, has always been openly accessible to the public, which was what the scientists argued at court during audits of their work.
The data had always been publically available.
This is obvious since even climate change skeptics have used this data in their own arguments.
So with that in mind, I've decided to see if I can't reproduce their climate temperature reconstruction. However I will confine myself only to the US Land Temperature Record. I admit this is simply because of a lack of time. I have a full-time job now. There's only a couple of hours I can dedicate to this project every week.
This week, after asking around a bit, I found a link to the FTP server where all the climate data has been stored, for version 1, 2 and 3. Both the adjusted gridded data and the raw data, as well as links to some articles detailing what kinds of adjustments the scientists have done.
Here it is in all its unvarnished glory. ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3
The data set I've got act as a summary of the monthly records of all the individual land stations, their maximum record, their minimum and their average reading. The data is unadjusted, at least by the GHCN.
I might one day get access to the raw data from the National Meteorological Services for comparison, but until that day I'll settle for the GHCN's data.
They've only done quality control on this data, removing stations that displayed repeating numbers for an entire day, or that suddenly spiked much higher or lower than stations around them. Unfortunately, I won't be able to do any verification on this step until I have access to the raw data from the National Meteorological Services, which will be a while.
I'll attempt to replicate the temperature reconstruction from the raw data. If all goes well, I can start to apply the adjustments they made, either by a set of different successive corrections for the biases mentioned in the beginning of this post. Or, as they did it, by the pair-wise homogenization algorithm. We'll see how far I get.
For the next Sunday, I should have a dirt-quick averaging of the data, and I'll attempt a gridded averaging as well, all with nice colorful charts.
Then in the following weeks, I'll go into the specific adjustments made.
This has been a claim thrown around a lot in various articles that cast doubt on whether the science of Global Warming is driven by science or political bias. Typically it is done by taking a graph of the "raw" temperature and subtracting ti from the "adjusted" temperature, and showing that the new adjusted reconstruction tends to make past temperatures colder and newer temperatures warmer.
This has led to suspicion that the various climate groups who have done these temperature reconstructions have their thumb on the scale. Biasing it towards higher temperatures.
I've countered that the adjustments were well founded. They are there to remove bias introduced by a shift of observation time, to changes of instruments, and even the urban heat island or urban cold island effects, and done with good reason. And that the raw data, at any rate, has always been openly accessible to the public, which was what the scientists argued at court during audits of their work.
The data had always been publically available.
This is obvious since even climate change skeptics have used this data in their own arguments.
So with that in mind, I've decided to see if I can't reproduce their climate temperature reconstruction. However I will confine myself only to the US Land Temperature Record. I admit this is simply because of a lack of time. I have a full-time job now. There's only a couple of hours I can dedicate to this project every week.
This week, after asking around a bit, I found a link to the FTP server where all the climate data has been stored, for version 1, 2 and 3. Both the adjusted gridded data and the raw data, as well as links to some articles detailing what kinds of adjustments the scientists have done.
Here it is in all its unvarnished glory. ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3
The data set I've got act as a summary of the monthly records of all the individual land stations, their maximum record, their minimum and their average reading. The data is unadjusted, at least by the GHCN.
I might one day get access to the raw data from the National Meteorological Services for comparison, but until that day I'll settle for the GHCN's data.
They've only done quality control on this data, removing stations that displayed repeating numbers for an entire day, or that suddenly spiked much higher or lower than stations around them. Unfortunately, I won't be able to do any verification on this step until I have access to the raw data from the National Meteorological Services, which will be a while.
I'll attempt to replicate the temperature reconstruction from the raw data. If all goes well, I can start to apply the adjustments they made, either by a set of different successive corrections for the biases mentioned in the beginning of this post. Or, as they did it, by the pair-wise homogenization algorithm. We'll see how far I get.
For the next Sunday, I should have a dirt-quick averaging of the data, and I'll attempt a gridded averaging as well, all with nice colorful charts.
Then in the following weeks, I'll go into the specific adjustments made.
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