TRMM provides a closer look at hurricanes using a unique combination of passive and active microwave instruments designed to peer inside cloud systems and measure rainfall. TRMM allows scientists to study the combustion process in the hurricane engine and relate this process to intensification or weakening.Hurricane Energy Process - As water vapor is evaporated from the warm ocean surface, it is forced upward in towering convective clouds in the eyewall and rain band regions of the storm. As the water vapor changes from a gas to a liquid (cloud water), latent heat is released. Note: This is the standard definition version of the Hurricane Heat Engine - Molecular View animation MPEG. Animator: Susan Twardy (HTSI). Scientist: J. Marshall Shepherd (NASA/GSFC).