nimbostratus cloud

in atmospheric chemistry
https://doi.org/10.1351/goldbook.N04143
An amorphous, dark grey, rainy cloud layer reaching almost to the ground; \(300-600\ \text{m}\) vertical velocities of \(0.05-0.2\ \text{m s}^{-1}\).
Source:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2180 [Terms] [Paper]