Download original image
The phase diagram gives one point per year for the period 1844–2011. The left-hand diagram is for the standard data; the other is for the Lockwood data. Data prior to 1968 are from Nevanlinna & Kataja (1993) in the two panels. From 1968 onward the aamin data are as given in Figure 2. The abscissa and ordinate of the horizontal and vertical lines are the coordinates of the Transition Point. There is a difference between the value of the ordinate of the Transition Point for the standard data (left) as compared with that derived with the Lockwood data.