Why is incoming shortwave radiation higher in early February than it is in early August at this location?

Incoming shortwave radiation (such as ultraviolet radiation) is at a peak when the sun is directly overhead an area. In February, the position of the earth relative to the sun is such that the sun is faced directly at this portion of the earth when it is daytime in the area of discussion. In contrast, in early August, the position of earth must be at such as position that the sun faces the area at an angle to the earth during daytime hours; hence, less shortwave radiation permeates the atmosphere. This is the reason why shortwave radiation is so sparse at the poles of the earth; it is because the sun is never directly overhead the poles of the earth during its rotation and/or revolution. The sun always faces the poles at sharp angles, minimizing shortwave radiation at the poles relative to places where the sun can be directly overhead the area.