Why are tropical savanna climates found in bands north and south of the tropical wet climates?

Tropical savanna climates are located in bands north and south of tropical wet climates primarily due to the influence of the Intertropical Convergence Zone (ITCZ) and seasonal shifts in the subtropical high-pressure systems. The ITCZ brings heavy rainfall during certain months, creating the wet conditions of tropical climates, while the surrounding areas experience a distinct dry season, leading to the grassland characteristics of savannas. Additionally, the geographical distribution of land and ocean affects the temperature and precipitation patterns, further defining these climate zones.