Question

What happens to the Hadley cell in Summer solstice?

Answer 1

During the Northern Hemisphere's summer solstice around June 21, the Hadley cell and subtropical ridge shift northward. This brings clearer and drier weather in the subtropics while intensifying rainfall near the equator due to the northward movement of the ITCZ.

Step-by-step explanation:

The Hadley cell is an atmospheric circulation pattern in the Earth's tropics that is altered during the summer solstice. During the Northern Hemisphere's summer solstice, which occurs around June 21, the subtropical ridge of high pressure moves northward due to the Earth's tilt and the direct overhead sun position moving to the Tropic of Cancer. This causes the Hadley cells to also shift northward, expanding their influence into higher latitudes.

The result is typically stronger and more established high-pressure areas in the subtropics, often bringing clear skies and drier weather to regions under its influence. Conversely, regions near the equator may experience stronger rainfalls as the Intertropical Convergence Zone (ITCZ) also migrates northward, enhancing convective activity.

Furthermore, during the summer solstice, the Northern Hemisphere receives more direct sunlight and for a longer duration each day. This results in warmer temperatures and has a heating effect on land and oceans which can lead to changes in local weather patterns, affecting the Hadley cell circulation. Over time, this extra heat absorption leads to the warmest months being July and August, even though they are after the solstice.

Answer 2

During the summer solstice, the Hadley cell in the Northern Hemisphere shifts northward due to the tilt of the Earth's axis, resulting in longer daylight hours and more intense weather patterns like heat and monsoons.

Step-by-step explanation:

What happens to the Hadey cell during the summer solstice is associated with the shift in the Earth's tilt towards the Sun. As mentioned, during the summer solstice on June 21st, the Northern Hemisphere experiences the longest day of the year. This occurs because the North Pole is tilted closest to the Sun, which is directly overhead at the Tropic of Cancer at a latitude of 23° N.

The Hadley cell is a large-scale atmospheric circulation pattern in which warm air rises near the equator, flows poleward at high altitudes, descends in the subtropics, and flows back towards the equator. The position of the Sun directly over the Tropic of Cancer during the summer solstice enhances the intensity of solar radiation in the Northern Hemisphere, particularly heating the tropical regions and intensifying the upward motion of warm, moist air.

As a result, the Hadley cell's ascending limb, which is normally positioned over the equator, tends to shift northward along with the zone of maximum solar heating. This shift expands and strengthens the Hadley cell in the Northern Hemisphere, leading to more pronounced weather patterns such as intense heat and, in some regions, monsoons. It’s important to note that while daylight hours are longest at the summer solstice, there is a lag in peak temperatures, as oceans and landmasses take time to heat up. The warmest months often follow the solstice due to this thermal inertia.