四、請針對以下火羽在溫度層化環境下(Plumes in Temperature - Stratified
Ambients)的描述，解讀附圖的物理現象。

火災科學 1
原文：When a buoyant, turbulent plume rises, it cools by entrainment of
ambient air. If the ambient air increases in temperature with height, which is
normal in buildings, and the fire source is weak, the temperature difference
between the plume and the ambient, which gives the plume buoyancy, may
vanish and actually reverse in sign. Eventually the plume ceases to rise.

Figure: Theoretical behavior of centerline plume variables in linearly
temperature-stratified ambients. Curve A: ratio of temperature rises (stratified
versus unstratified), Curve B: ratio of axial velocities. Curve C: ratio of plume
radii. Curve D: ratio of volumetric species concentrations. Where z: height
above top of combustible (m) and Zm: maximum vertical penetration of plume
fluid in stratified ambient (m)

火災科學 2