When broken down, Helicity and CAPE actually have the same basic units. The units of CAPE are often expressed as Joules per kilogram (Jkg^-1) The units of Helicity are often expressed as meters squared per seconds squared (m^2s^-2) Here is how the units of Jkg^-1 can be simplified to m^2s^-2 A Joules is a Newton times a meter (Nm). A Newton is a kgms^-2. A Newton times a meter (a Joule) is kgm^2s^-2. The units of Joules divided by kg yields the units of m^2s^-2 |