The major non-gas contributor to Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the greenhouse gases.
What is Imitrex? Imitrex (sumatriptan) is a headache medicine that narrows blood vessels around the brain. Sumatriptan also reduces substances in the body that can trigger headache pain, nausea, sensitivity to light and sound, and other migraine symptoms. Imitrex is used to treat migraine headaches. Imitrex will only treat a headache that has already begun. It will not prevent headaches or reduce the number of attacks.
By that, I mean if I'm going to take a dose to get high, I need to take the correct dose all at once. Any doses taken after that first one usually don't have quite the desired accumulative effect. For you, however, sumatriptan succinate brand name might work... that's just what I've found over time. Some of that also has to do with tolerance, of course (not just to dose but to duration of action as well) but that has always been an issue for me.