The C-Shaped Landmass: A Key Driver of Monsoon Formation

Abstract

Monsoon dynamics research has largely focused on idealized rectangular continents, primarily in the Northern Hemisphere mid-latitudes. To investigate the broader impact of landmass configuration on monsoon formation and variability, we conducted extensive sensitivity experiments. Our findings reveal that a C-shaped continent in the tropical and subtropical latitudes is optimal for monsoon development. This configuration fosters three key monsoon characteristics: (a) A well-defined pathway for water vapor transport, involving cross-equatorial winds and monsoonal trough turning winds; (b) A thermally induced low-pressure system over the southeastern continental margin, driving persistent water vapor convergence; and (c) A distinct monsoon rain belt extending from the southeastern corner of the continent into adjacent oceans. These results provide a definitive answer to the question of which landmass shape is most conducive to monsoon formation and significantly advance our understanding of monsoon dynamics.