4.1.8 Day 1, 6PM: Temperature gradient

graphic for interaction asking users to select the right direction and strength of the thermal gradient in a nighttime snowpack scenario with radiational cooling

What would you expect to happen to the temperature gradient in the upper portion of the snowpack during the night if atmospheric conditions are clear and calm. Select the vector that corresponds to the correct strength and direction of the thermal gradient, then click Done. Note that the vectors point from cold to warm, with their widths representing the strength of the gradient (strong vs. weak).

The correct answer is b.

Radiative cooling will maximize as the evening progresses. The top few millimeters of the snowpack will cool very rapidly, resulting in a strong temperature gradient directed downwards.