This scene occurs when direct sunlight

 This scene occurs when direct sunlight, rainfall, and observer position align within a very narrow geometric range. A rainbow is not an object in the sky and it is not located at a fixed place. It is an optical phenomenon created by the interaction of sunlight with countless suspended water droplets in the atmosphere.

Each droplet acts as a tiny refractive system. Incoming sunlight is refracted, then internally reflected, and refracted again as it exits the droplet. During this process, white sunlight is separated into its component wavelengths, producing the visible spectrum from red to violet. The fixed angle of this refraction, approximately 42 degrees for the primary rainbow, determines the circular arc seen by the observer.

The second, fainter arc above the first forms when light undergoes two internal reflections inside the droplets instead of one. This reverses the color order and reduces intensity, which is why the outer arc appears dimmer and inverted.

The intense golden illumination in this scene is caused by the low solar elevation near sunset. At this angle, sunlight travels through a much longer path in the atmosphere. Shorter wavelengths (blue and violet) are scattered more strongly by air molecules, allowing longer wavelengths (orange and red) to dominate the direct light reaching the landscape.

The calm water surface acts as a specular reflector, mirroring the sky with minimal distortion. When wind is low and the surface is smooth, reflected light preserves the geometry of the rainbow and the solar disk, creating the near-symmetrical appearance seen here.

Cloud structure plays a crucial role. The dark background enhances contrast, while gaps in the cloud layer allow direct solar rays to illuminate rain-filled regions behind the observer.