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Showing posts with the label US temperature

Correcting for Time of Observation Bias

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You'll frequently see contrarian influencers on social media showing the differences between "raw" and "adjusted" temperatures for the United States that indicate that CONUS warming in the "adjusted" temperatures is greater than in the "raw" data. We're often told this indicates that scientists have adjusted CONUS temperatures to make them cooler in the past, thus making the amount of warming that has occurred in the US larger in the "adjusted" temperature data than in the "raw" data. It's then frequently just assumed that this is because "liberal" scientists need are conspiring with nefarious intent to tamper with and manipulate temperature data to create artificial warming trends in US temperatures. In another post I share some dishonest way in which contrarians exaggerate the difference between the "raw" and adjusted temperatures, but even in properly plotted comparisons, the final "adju...

2024 CONUS Temperatures

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NOAA has released their December 2024 results for both nClimDiv and USCRN US temperatures, and 2024 turned out to be the warmest year for CONUS on record (records beginning in 1895). NOAA's website reports CONUS for 2024 as 55.51°F. Below I show several graphs for nClimDiv, with monthly temperatures, a 12-month running mean, and a 10-year running mean. ERA5 for CONUS is also out, and to make apples to apples comparisons, I changed nClimDiv to Celsius and set it to a 1951-2000 baseline. USCRN began recording CONUS temperatures in 2005, so the end of 2024 marks the 20th year for that dataset. Below I show graphs comparing USCRN to both nClimDiv and UAH-TLT for CONUS. Here's how USCRN compares to ERA5, with the scale switched to Celsius to match ERA5. Since USCRN only goes back to 2005, I can't give you 30-year trends, but CONUS is warming so rapidly, that the last 20 years is already statistically significant. From Jan 2005 to Dec 2024, CONUS trends were: USCRN: 0.451 ± 0.241...

Data Tampering by Shewchuk and Heller

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If you follow climate discussions on X, you're bound to see John Shewchuk and/or Tony Heller show graphs that reportedly show that NOAA is tampering with temperature data to fabricate global warming with spurious warming trends. I've gone over many of the reasons why this is nonsense before in posts about bias correction and so-called  ghost stations . I think it's good to show what's actually going on with the graphs they present as "proof" of data manipulation, though. I think it can be easily demonstrated here that it's actually Shewchuk and Heller that are tampering with data. Shewchuk (Top) and Correct (Below) Above are two graphs. The top graph shows what John Shewchuk claims shows that NOAA is manipulating data. It shows USHCN "raw" and "altered" Tmax data for 1900 to 2023. The bottom graph above is the correct plot of NOAA's published data from the current and correct dataset (nClimDiv) with a 5-year running mean to match S...