暖かい軽い空気は山越えすると上空に上昇し、地上には下りてこないことなど、風は地形によって変わります。

、、。

Warm, light air rises into the upper atmosphere when it crosses a mountain and doesn't descend back to ground level — through such effects, wind behavior changes with the terrain.

Literal

Warm light air [topic-は] mountain-crossing [when-と] upper-sky [to-に] ascending-and, ground-surface [to-には] descend-come-not thing [such as-など], wind [topic-は] terrain [by means of-によって] changes.

A textbook-style example sentence. Two topic markers (は) structure the flow: 暖かい軽い空気は sets up the warm-air example, then 風は returns to the broader topic of wind. Between them, a nominalized clause ~ないことなど ('things such as the fact that it doesn't come down') bundles the example and hands it off as background for the main claim. ~によって ('depending on,' 'according to') marks the causal variable — the terrain — that drives the variation. Note ~と as a 'when / whenever' conditional here, not the quotative or conjunctive と; it expresses an automatic/natural consequence.