What is the phenomenon of sublimation?

<p style=";text-align:left;direction:ltr">Weather of Arabia - The phenomenon of the sun perpendicular to the Kaaba is known as “transcendence.” This phenomenon occurs twice a year, taking into account the leap year. The first time is on May 27 or 28, when the sun apparently moves north from the equator towards the Tropic of Cancer, passing the latitude of Mecca (21.425 degrees north).</p><p style=";text-align:left;direction:ltr"> The second time occurs on July 15 or 16, when the sun returns in its apparent movement south from the Tropic of Cancer to the equator, and again crosses the latitude of Mecca.</p><p style=";text-align:left;direction:ltr"> At the moment of noon, the sun is completely vertical above the Kaaba, causing its shadow and the shadows of all objects in the holy city of Mecca and its surrounding areas to disappear.</p><p style=";text-align:left;direction:ltr"></p>