Which radar band would experience the most attenuation from H2O?

The K-band is known for experiencing significant attenuation due to water vapor and precipitation. This band operates at higher frequencies (around 18 to 27 GHz), where atmospheric absorption becomes more pronounced. As the frequency increases, the impact of moisture in the atmosphere—specifically water vapor and raindrops—on radar signals also increases. This leads to higher levels of signal loss as the radar wave encounters water in various forms, whether as vapor in the atmosphere or as rain.

In contrast, the other bands (L-band, S-band, and X-band) operate at lower frequencies, where the attenuation caused by water is less severe. Although X-band radar can also experience attenuation to some extent, particularly during heavy precipitation, it is generally less than that experienced at K-band frequencies. The S-band and L-band, being the lowest frequencies in this selection, are even more resilient to moisture-related attenuation, making them more suitable for long-range weather radar applications where signal integrity is crucial.

Thus, due to its higher frequency and the properties of electromagnetic waves interacting with water particles, the K-band would experience the most attenuation from H2O.