Dave has pointed us to a particular site that he says has the raw data and he urges me to use that data. So I will. I decided to look at Hallettsville and Flatonia Texas for the year 1977. I had previously, from the CO2science.com site seen large annual average temperature differences between Hallettsville and Flatonia around 1977. So I downloaded that year from
Now remember that this site claims that they have already edited out large standard deviation anomalies, so the data is partly edited. In spite of the claim to be raw data it isn't. They have also already done some areal adjustments, meaning that they have compared nearby towns. I will say that they didn't catch them all but that is for another post on another day about another pair of towns.
The first thing I did was download the chart of the annual temperature. And there it is, that weird jump in temperature at Hallettsville in 1977. It is about a 3 degree change.
So, the next thing I did for 1977 was to compare Hallettsville's temperature with the nearest town in the USHCN, Flatonia, TX. Flatonia is only 17 miles from Hallettsville and the topography is quite similar. I have been through these two towns during my career and they are both on the flat Texas Prairie. They should have very minor differences in temperature even on a daily basis but most assuredly on an annual basis. There are no mountains in that part of Texas.
So, I subtracted Flatonia's temperature from that of Hallettsville's and saw that the temperature difference was quite large throughout the year, mostly with Hallettsville being hotter.
The annual average difference in temperature between these two towns is 2.84 degrees F. You might be tempted to say that this isn't all that much. If so, that would be wrong.
A suggested set of criteria based on the horizontal temperature gradient has been devised. A weak front is one where the temperature gradient is less than 10[deg]F per 100 miles; a moderate front is where the temperature gradient is 10 [deg]F to 20 [deg]F per 100 miles; and a strong front is where the gradient is over 20 [deg]F per 100 miles.
A strong front is 10 degrees per hundred miles. That works out to be 0.1 degree F per mile. The annual temperature gradient between Hallettsville and Flatonia 17 miles away is 0.17 deg F per mile, almost twice that of a strong cold front! And it lasted for a year's duration, or a significant part of that year.
Now, why did I choose two neighboring towns? Because this is as close as we can come to actually verifying via duplication the temperature. By choosing two towns on the hot Texas prairie, where there are no mountains. Even making the adiabatic lapse rate correction, the temperature difference is still above 2.5 deg F for the year, giving an adiabatically corrected gradient of .15 deg F/mile.
Now, what does this gradient mean? As I said above it is more than 1.5 x the temperature gradient along a strong cold front. Such cold fronts bring rain, winds and thunderstorms, yet, for the year 1977, there were no year long storms over Hallettsville and Flatonia. In other words, this temperature difference could not possibly have existed or we would have seen accompanying weather phenomenon.
Temperature differences like these would lead to wind blowing most of the year from Hallettsville to Flatonia, NW winds, which are extremely unusual in that part of Texas. Below is the chart of the daily gradient, the 30 day running average gradient along with markers for the January equator to North Pole temperature gradient and markers for that due to a cold front. You can see that the temperature differences between these two towns is very large by any measure available.
Now, I ran a 30-day running average over the temperature difference. The first output point is 41 days into 1977 because Flatonia is missing data and I didn't want to plot the data before the first full 30-day running average point. It is the last picture.
Flatonia, not Hallettsville, has missing January data. I want to point that out because I am sure that Dave will want to claim that that is why Hallettsville has the high annual temperature in 1977. But that explanation can't be offered because as the first picture shows, Hallettsville, which is not missing data becomes suddenly very warm compared to Hallettsville, not compared to Flatonia. The sudden warmth in Hallettsville is real and not a factor of missing data.
Under the assumption that these two towns, only 17 miles apart should have nearly identical temperatures throughout the year,and thus are effectively quasi-repeated measurements, we can use the two towns as a measure of the noise in the raw data. The noise level is large. The blue bar is the magnitude of the yearly spread, 3.7 deg F. That becomes the error bar for the dataset used to calculate the global warming which is now pegged at around 1.1 deg F over the past century. Thus the signal we are trying to detect is 0.11 +/- 1.85 degree F for each year. (half of the 3.7 excursion). Anyone familiar with science knows that this is far too small to be detected against this noise level. So, if temperatures are not repeatable, as this shows, we can't really know what is happening globally. The data is crap. Maybe Dave should have a critical look at the data he thinks is good.