An unsaturated parcel of air in Boulder, Colorado, rises from a surface temperature of 24ºC and an elevation of 1655 m to an elevation of 4155 m without reaching the dew-point temperature. What is the temperature of the parcel at this elevation?

To determine the temperature of an unsaturated parcel of air as it rises from 1655 m to 4155 m, you can apply the concept of dry adiabatic lapse rate, which is approximately 10ºC for every 1000 meters of elevation gain.

Starting with the surface temperature of 24ºC at 1655 m, the elevation gain to 4155 m is 2500 m. Since the air parcel remains unsaturated during this ascent, it will cool at the dry adiabatic lapse rate of 10ºC per 1000 m.

Calculating the temperature drop, we find that rising 2500 m results in a cooling of 25ºC (10ºC for each 1000 m multiplied by 2.5).

The initial temperature of 24ºC, minus the 25ºC cooling, gives a temperature of -1ºC at the new elevation of 4155 m. This result aligns with the characteristics of unsaturated air parcels, which cool following the dry adiabatic lapse rate until they reach lower temperatures, confirming that -1ºC is indeed the correct temperature for the parcel at that elevation.