Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.
Frontal precipitation occurs when a front or boundary line is formed between two air masses of contrasting temperature. Along the fronts, the warm air rises above the denser cold air. The mid-latitude regions experiencing the convergence of warm tropical and cold polar air masses are important areas receiving frontal precipitation.
EXAMIANS