Condensation level কী?

Example 4.9 (An afternoon cumulus)

In the afternoon of Example 4.4, the air at the ground is at $28{}^{\circ}\mathrm{C}$ with a dew point of $16{}^{\circ}\mathrm{C}$. Rising bubbles become saturated at $125 \times 12 = 1500\,\mathrm{m}$: the cumulus have their flat bases about $1.5\,\mathrm{km}$ up. In the morning, at $20{}^{\circ}\mathrm{C}$, the same air would have condensed at only $125 \times 4 = 500\,\mathrm{m}$: cloud bases rise through the day as the ground warms.