Chopra Gaurav, Unni Vishnu R, Venkatesan Praveenkumar, Vallejo-Bernal Sara M, Marwan Norbert, Kurths Jürgen, Sujith R I
Department of Aerospace Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India.
Centre for Excellence for studying Critical Transitions in Complex Systems, Indian Institute of Technology Madras, Chennai, Tamil Nadu, 600036, India.
Sci Rep. 2024 Oct 18;14(1):24463. doi: 10.1038/s41598-024-73872-0.
The Intertropical Convergence Zone (ITCZ) is a narrow tropical belt of deep convective clouds, intense precipitation, and monsoon circulations encircling the Earth. Complex interactions between the ITCZ and local geophysical dynamics result in high climate variability, making weather forecasting and prediction of extreme rainfall or drought events challenging. We unravel the complex spatio-temporal dynamics of the ITCZ and the resulting teleconnection patterns via a novel tropical climate classification achieved using complex network analysis and community detection. We reduce the high-dimensional complex ITCZ dynamics into a simple yet insightful community structure that classifies the tropics into seven regions representing distinct ITCZ dynamics. The two largest communities, encompassing landmasses over the Northern and Southern hemispheres, are associated with coherent seasonal ITCZ dynamics and have significant long-range connections. Temporal analysis of the community structure highlights that the tropical Pacific and Atlantic Oceans communities exhibit substantial variation on multidecadal scales. Further, these communities exhibit incoherent dynamics due to atmosphere-ocean interactions driven by equatorial and coastal oceanic upwelling.
热带辐合带（ITCZ）是环绕地球的一条狭窄的热带地带，有深厚的对流云、强降水和季风环流。ITCZ与当地地球物理动力学之间的复杂相互作用导致了高度的气候变率，使得天气预报以及极端降雨或干旱事件的预测具有挑战性。我们通过一种利用复杂网络分析和群落检测实现的新型热带气候分类方法，揭示了ITCZ复杂的时空动力学以及由此产生的遥相关型。我们将高维复杂的ITCZ动力学简化为一个简单而有洞察力的群落结构，该结构将热带地区划分为七个区域，代表不同的ITCZ动力学。两个最大的群落，涵盖了北半球和南半球的陆地，与连贯的季节性ITCZ动力学相关，并具有显著的长程连接。对群落结构的时间分析表明，热带太平洋和大西洋群落在年代际尺度上表现出显著变化。此外，由于赤道和沿海海洋上升流驱动的海气相互作用，这些群落表现出不连贯的动力学。
