Figure-4.2: How artifacts in instrument data can affect temperature change estimates

Photos of the observing site Amos, Quebec, taken by inspectors showing the site before 1963 (a) and after 1963 (b). (c) Time series of the difference in the annual mean of the daily minimum temperatures between Amos and a reference station shows a decreasing step in 1927 and an increasing step in 1963, (d) The original (red line) and adjusted (blue line) time series of the annual mean of the daily minimum temperatures. The red dashed line shows an increasing trend of 2.4°C for 1915–1995 in the original series, while the blue dashed line shows an increasing trend of 0.8°C for 1915–1995 in the homogenized data.

Source

Climate Research Division, Environment and Climate Change Canada.