For this and the next five questions, Assume the following:

Surface Temperature = 35⁰C
Surface Dew Point Temperature = 19⁰C
Dry Adiabatic Lapse Rate (DALR): 10⁰C km⁻¹
Wet (moist) Adiabatic Lapse Rate (WALR): 5⁰C km⁻¹

Assume Dew Point Temperature decrease with altitude at 2⁰C km-1 if un-saturated as you ascend (and increases at the same rate as you descend) due to pressure changes.

Lift a parcel of air as high as 3000m (3 km) over a mountain and then allow it to descend back to the surface on the other side.

What is the Height of the Lifting Condensation Level (LCL) (above point A)?

a. 500 m
b. 1000 m
c. 1500 m
d. 2000 m
e. 2500 m

The Height of the Lifting Condensation Level (LCL) is determined by finding the altitude at which an air parcel cools to its dew point. With a surface temperature of 35℃ and dew point of 19℃, and given lapse rates, the LCL is found at 2000 meters.

Explanation:

To find the Height of the Lifting Condensation Level (LCL), we need to determine the altitude at which the parcel of air being lifted over the mountain would cool down to its dew point temperature and condensation would begin. Given that the surface temperature is 35℃ and the surface dew point is 19℃, the dry adiabatic lapse rate is 10℃ km−1 and the dew point decreases at a rate of 2℃ km−1 if unsaturated, we can calculate the LCL.

The temperature difference between the surface temperature and the dew point is 35℃ - 19℃ = 16℃. Since the rate of temperature decrease is 10℃ km−1 and the dew point decreases by 2℃ km−1, for each kilometer the temperature drops by 10℃ while the dew point drops by 2℃, maintaining a difference of 8℃ per kilometer between the two. To close the 16℃ gap entirely and reach the LCL we thus need 16℃ / 8℃ km−1 = 2 km of ascent.

Therefore, the correct answer is d. 2000 m.

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