The OP is taking the machine into tropical climates; you can easily add 15-20 degrees to your quoted temperatures and you're already pushing the envelope before you even start loading the machine.
OP also wants to do serious data crunching in these conditions.
The Air would be highly risky.
(Also, just a note: I think anything over about 55 degrees C is uncomfortably warm when the machine is on my lap. My Macbook is currently showing 38 degrees C. I can't even imagine running something that burns at 75 degrees. This would also shorten the life of the machine, since it runs all the metal components through more extreme warming-cooling cycles. None of this is worth the extra pound and a half or so you save with the Air. I have owned two Airs, and returned them both.)
The system will handle up to the heat. I'm 100% sure of it. Tropical areas are fine for the air or any laptops in fact. It'll be slower compared to the MBP, should be, but beyond that, it's the same.
I'm sorry if you believe you'll have a bomb on your lap if it reaches over a xx amount of temp, but I'm pretty sure many people have used their systems at higher temps for a lot longer time without any problems.