! Southern Ocean change
set region/y=20:70/x=100:265
set view upper
plot/vlim=35.0:37.2/title="change between 1990 and 1960" atrac[d=1,y=@ave,x=@ave,l=110]-atrac[d=1,y=@ave,x=@ave,l=80]
set view lower
plot btrac[d=1,y=@ave,x=@ave,l=110]-btrac[d=1,y=@ave,x=@ave,l=80]
message
cancel region
cancel view

! North Atlantic Change
let na=atrac[d=1]*mask_3a[d=2,k=1,l=1]
let na1=btrac[d=1]*mask_3a[d=2,k=1,l=1]

set view upper
plot/vlim=35.0:37.2 na[l=110,x=@ave,y=@ave]-na[l=80,x=@ave,y=@ave]

set view lower
plot na1[l=110,x=@ave,y=@ave]-na1[l=80,x=@ave,y=@ave]