Question: What does the dbz chart stand for on the Radar Image for National Weather Chart?

Answer: Dbz is the "unit" of radar reflectivity. It represents a logarithmic power ratio (in decibels, or dB) with respect to radar reflectivity factor, Z. The value of Z is a function of the amount of radar beam that is returned by a target and detected as an echo. Higher values of Z, and dBZ, would indicate more energy being reflected and a higher dBZ usually means higher precipitation rates.