Explain how IDF curves (see Figure) are statistically developed for any urban rainfall gag...

Explain how IDF curves (see Figure) are statistically developed for any urban rainfall gage. Assume that data are available for 5-, 15-, 30-, and 60-min intervals up to 24 hr.

Figure

Variation of lapse rates and different types of atmospheric conditions. When air is colder than its surroundings and rises, it results in what is called a stable atmosphere. On the other hand, when warmer air rises, it results in an unstable atmosphere (greater movement of air).

(a) The unsaturated parcel of air at each elevation is colder than its surroundings. The atmosphere is stable with respect to unsaturated, rising air.

(b) The lifted, saturated air parcel is warmer at each elevation than its surroundings. The atmosphere is unstable with respect to saturated, rising air.