variable size of marks in scatter plots

[Alfredo Ruiz-Barradas]

Dear GrADS users,

I am making a scatter plot using two time series but I want that the size
of the plotted marks change according to the magnitude of a given criteria
(another time series). That is, if the magnitude of the time series of
reference is small I want a small mark, if it is large I want a big mark.

Any idea how to achieve this will be greatly appreciated.

Many thanks,
Alfredo