A TimeOffset Axis where the offsets depend on the runtime hour since 0z.
A real life example from NAM-Polar_90km.ncx4:
validtime1 runtime=reftime nruns=123 ntimes=52 isOrthogonal=false isRegular=true
hour 0: timeIntv: (0,1), (0,2), (0,3), (0,4), (0,5), (0,6), (6,7), (6,8), (6,9), (6,10), (6,11), (6,12), (12,13), (12,14), (12,15), (12,16), (12,17), (12,18), (18,19), (18,20), (18,21), (18,22), (18,23), (18,24), (24,25), (24,26), (24,27), (24,28), (24,29), (24,30), (30,31), (30,32), (30,33), (30,34), (30,35), (30,36), (36,39), (36,42), (42,45), (42,48), (48,51), (48,54), (54,57), (54,60), (60,63), (60,66), (66,69), (66,72), (72,75), (72,78), (78,81), (78,84), (52)
hour 6: timeIntv: (0,1), (0,2), (0,3), (3,4), (3,5), (3,6), (6,7), (6,8), (6,9), (9,10), (9,11), (9,12), (12,13), (12,14), (12,15), (15,16), (15,17), (15,18), (18,19), (18,20), (18,21), (21,22), (21,23), (21,24), (24,25), (24,26), (24,27), (27,28), (27,29), (27,30), (30,31), (30,32), (30,33), (33,34), (33,35), (33,36), (36,39), (39,42), (42,45), (45,48), (48,51), (51,54), (54,57), (57,60), (60,63), (63,66), (66,69), (69,72), (72,75), (75,78), (78,81), (81,84), (52)
hour 12: timeIntv: (0,1), (0,2), (0,3), (0,4), (0,5), (0,6), (6,7), (6,8), (6,9), (6,10), (6,11), (6,12), (12,13), (12,14), (12,15), (12,16), (12,17), (12,18), (18,19), (18,20), (18,21), (18,22), (18,23), (18,24), (24,25), (24,26), (24,27), (24,28), (24,29), (24,30), (30,31), (30,32), (30,33), (30,34), (30,35), (30,36), (36,39), (36,42), (42,45), (42,48), (48,51), (48,54), (54,57), (54,60), (60,63), (60,66), (66,69), (66,72), (72,75), (72,78), (78,81), (78,84), (52)
hour 18: timeIntv: (0,1), (0,2), (0,3), (3,4), (3,5), (3,6), (6,7), (6,8), (6,9), (9,10), (9,11), (9,12), (12,13), (12,14), (12,15), (15,16), (15,17), (15,18), (18,19), (18,20), (18,21), (21,22), (21,23), (21,24), (24,25), (24,26), (24,27), (27,28), (27,29), (27,30), (30,31), (30,32), (30,33), (33,34), (33,35), (33,36), (36,39), (39,42), (42,45), (45,48), (48,51), (51,54), (54,57), (57,60), (60,63), (63,66), (66,69), (69,72), (72,75), (75,78), (78,81), (81,84), (52)
An orthogonal TimeOffset means the same offsets for any runtime, so both runtime and timeOffset are 1D.
A regular Timeoffset means it varies based on the hour of the runtime from 0Z.