This question is difficult to interpret. The "pull" of a tornado is related to the low pressure inside rather than to gravity. Newton coined the term gravity for what he hypothesized was the attraction between object with mass, the earth being the most massive object in our location and hence the greater gravity. Einstein came up with a different explanation of why we are "held" to the surface, that involves inertia and doesn't require the notion of a force like gravity. In schools Newton's ideas are still taught because they are mathematically simple in comparison to Einstein's, but on the largest scales, Einstein wins out in accuracy. The atmosphere is held to the earth because of its inertia - it doesn't have the energy to escape the earth's "gravitational field" - tho some very light gases can indeed escape, like helium. Don't know if I have answered your question but I hope this helps.