3. Stability

Other Instabilities » MAULs Moist Absolutely Unstable Layers (MAULs)

Conceptual sounding animation showing genesis of Moist, Absolutely Unstable Layer (MAUL)

Bryan and Fritsch (2000) posed that saturated layers may exist in the lower to middle troposphere that have lapse rates that exceed the moist-adiabatic lapse rate and are therefore moist absolutely unstable layers (MAULs). A MAUL may be better understood by considering the evolution of the sounding in this animation. The initially unsaturated 900-600 hPa layer is lifted 100 hPa and becomes saturated. The resulting lapse rate of the saturated 800-500 hPa layer is steeper than the moist-adiabatic lapse rate, hence the formation of a MAUL.