Search Results for: TOBS

The graph below is another TOBS killer. It shows the difference in summer temperature between US HCN stations which took morning readings on July 15, 1936 and those which took afternoon readings on that date. The trend is down, indicating … Continue reading →

One of the funnier claims about TOBS is that the frequency of 100 degree temperatures in the 1930’s was due to double counting at stations which reset their thermometers in the afternoon. I put that to the test by identifying … Continue reading →

The USHCN station at Ada, Minnesota took their temperature readings at 7 am during the 1930s. They show exactly the same pattern of very hot weather during the 1930’s, and much cooler since 1988. The “blame the hot 1930s on TOBS” … Continue reading →

Someone was trying to blame the high incidence of 100 degree readings during the 1930s on time of observation bias. Allegan, Michigan took their readings at midnight during the 1930’s, and showed the same pattern as the rest of the … Continue reading →

Imagine you are operating a temperature station in July, 1936 – the hottest month in US history. Your time of observation is 5 pm. The temperature is 109 degrees, and you reset your thermometer. At 6 pm, a cold front … Continue reading →

Someone was claiming last night that the high frequency of 100 degree readings during the 1930s was due to TOBS double counting. While I find it difficult to believe that anyone could be stupid and irresponsible enough to reset a … Continue reading →

If you have ever used a min/max thermometer, you are aware of the time of observation bias problem. It is not a subtle problem. Suppose you reset your thermometer at 3 pm, and the temperature is 60F. At 4 pm a … Continue reading →

According to USHCN docs, the V2 TOBS adjustment hasn’t changed since V1 This net effect is about the same as that of the TOB adjustments in the HCN version 1 temperature data (Hansen et al. 2001), which is to be … Continue reading →

You get your nice new Min/Max thermometer and set it up. First afternoon the temperature is 65F when you take you measurement at 4 pm and reset your thermometer. An hour later, a cold front comes through and the next … Continue reading →

Ignoring a host  of other issues about TOBS, according to USHCN V2 docs the USHCN V2 TOBS adjustment is supposed to look like this – positive since 1980, and slightly negative prior to that. This is somewhat similar to V1 … Continue reading →