The Mascarene High (MH), is a key component of the Asian‐Africa‐Australia monsoon system in austral winter (JJA), spanning over the South Indian Ocean (15°–35°S, 15°–110°E). Its three‐dimensional structures and maintenance mechanisms are examined in this study. It is a low‐level subtropical high dominating the southern Africa and South Indian Ocean, characterized by a north‐westward tilt with height, which is attributed to its...