Why can a horizontal antenna closer to ground be advantageous for close range communications on lower HF bands?

For close-range communications on lower HF bands (like 80m and 40m), operators often use a technique called Near-Vertical Incidence Skywave (NVIS). To achieve this, a horizontal antenna is mounted relatively close to the ground, typically at a quarter-wavelength high or less. At this low height, the ground acts as a reflector, bouncing the downward-radiating RF energy back up. This reflected energy combines with the upward radiation to push the majority of the signal straight overhead at a very high angle. The ionosphere then reflects this high-angle signal straight back down, effectively covering local and regional distances without a skip zone.