For all runs, the O+ minimum was imposed between -15 and +15
degrees geographic latitude.

Frame 1
Log10 O+: ut vs zp at latitude -1.25 (min,max all = -5,5.9)
Top left: O+ min=1.e2, zp >= 1.0
Top right: O+ min=1.e2, zp >= 2.5
Bottom left: O+ min=1.e3, zp >= 1.0
Bottom right: O+ min=1.e3, zp >= 2.5

Frame 2
Te: ut vs zp at latitude -1.25
Top left: O+ min=1.e2, zp >= 1.0 (min,max=150,8408)
Top right: O+ min=1.e2, zp >= 2.5 (min,max=150,9106)
Bottom left: O+ min=1.e3, zp >= 1.0 (min,max=150,4290)
Bottom right: O+ min=1.e3, zp >= 2.5 (min,max=150,5609)

Frame 3
Log10 Ne: ut vs zp at latitude -1.25
Top left: O+ min=1.e2, zp >= 1.0 (min,max=2.1,5.9)
Top right: O+ min=1.e2, zp >= 2.5 (min,max=2.1,5.9)
Bottom left: O+ min=1.e3, zp >= 1.0 (min,max=2.8,5.9)
Bottom right: O+ min=1.e3, zp >= 2.5 (min,max=2.4,5.9)

Frame 4
Log10 O+: ut vs latitude at Zp=3.8
Top: No O+ minimum (min,max=-5,6.1)
Left: opmin=1.e2, Zp >= 1.0 (min,max=2,6.1)
Right: opmin=1.e3, Zp >= 1.0 (min,max=3,6.1)

Frame 5
Te: ut vs latitude at Zp=3.8
Top: No O+ minimum (min,max=833,11388)
Left: opmin=1.e2, Zp >= 1.0 (min,max=833,8328)
Right: opmin=1.e3, Zp >= 1.0 (min,max=833,8197)

Frame 6
Log10 Ne: ut vs latitude at Zp=6.0
Top: No O+ minimum (min,max=1.9,5.7)
Left: opmin=1.e2, Zp >= 1.0 (min,max=2.2,5.7)
Right: opmin=1.e3, Zp >= 1.0 (min,max=3.0,5.7)