About.com is the only site I've ever seen to claim that long north-south flights get the same symptoms as jetlag experienced on other time-zone crossing flights.
Everywhere else, you'll hear that it happens changing timezones only.
Indeed, it's more likely that the long north-south ones are just 'tired' from the long flight, perhaps not sleeping, and the long journey, in the same way that you're tired after a long car ride.
However, having changed seasons mid-winter or mid-summer a few times, I can mention that:
from London to South Africa, and back, London to NZ and back several times, and between the US/Canada and NZ, I certainly noticed the daylight hours. And I suppose this would be a bit of a psychological shock the higher your latitude and the stage of the season. Going from 16 hours of daylight to 6 can be quite distressing, and I even found my first week mid-summer in the UK to be disconcerting with the crazy long evenings.
Between London and NZ you definitely get jetlag. Brutal if flying east. However between the US and Aus, hardly anything, and overnight from London to South Africa and back, I didn't notice anything.
But a word for it? Probably just 'tiredness' :)
So I assume you're talking about the day, or week following travel - however, it's worth noting that science has indeed found a link between latitude and how it affects your sleep.
“People who live near the Equator have a greater tendency to be early
risers and to sleep earlier. Closer to the poles, individuals become
more vespertine (rising later and going to sleep later),” said Mario
Pedrazzoli, professor in the Universidade de São Paulo (USP) School of
Arts, Sciences and Humanities