In a landmark study spearheaded by Professor Kyong-Hwan Seo of Pusan National University in South Korea, groundbreaking insights have emerged concerning the profound influence of aerosols on the precipitation patterns of the Maritime Continent. This region, encompassing extensive parts of Southeast Asia such as Indonesia, Malaysia, Singapore, Vietnam, Thailand, the Philippines, and their surrounding seas, is critically dependent on regular rainfall cycles for agricultural sustainability, water resources, and flood control. Seo’s team has, for the first time, intricately mapped how elevated aerosol concentrations—originating from biomass burning, urban pollution, and emissions— reshape the spatial and temporal characteristics of rainfall in this climatically complex region.
Utilizing a high-resolution atmospheric model resolved at 2 kilometers, integrated meticulously with NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite data and the MERRA-2 reanalysis datasets, the study investigates aerosol-induced modifications to convection and precipitation dynamics under different atmospheric states. The researchers focused on a striking Madden-Julian Oscillation (MJO) event from 2011, though they extended their methodology across various MJO phases and multiple years for robustness. The simulations unveiled that heavy aerosol loading consistently intensified precipitation over oceanic regions, sometimes by as much as 50%, while concurrently suppressing rainfall over adjacent land masses—a hitherto unknown phenomenon.
The core mechanism behind these transformations arises primarily from radiative forcing disparities between land and ocean surfaces influenced by aerosol presence. Aerosols induce enhanced scattering and absorption of sunlight, which preferentially cools the land areas more than the ocean. This differential cooling establishes atmospheric stability over islands, effectively suppressing convective activity on land. Conversely, the ocean remains relatively warm and unstable, fostering enhanced low-level convergence and vigorous convective processes offshore. The resultant wind patterns draw moist air seaward, further reinforcing intensified oceanic precipitation and a markedly increased sea-to-land rainfall ratio.
Professor Seo articulates, “Aerosols act like a brake on daytime heating over land, but the ocean hardly feels that brake.” The study’s sophisticated high-resolution simulations capture this interaction in unprecedented detail, revealing the spatial redistribution of moisture and energy within the lower troposphere. This insight challenges conventional paradigms that previously treated aerosol effects as spatially uniform or primarily detrimental to precipitation as a whole. Instead, this nuanced understanding illustrates complex aerosol–radiation interactions that reshape convective dynamics at regional scales.
Intriguingly, the aerosol-driven surface cooling over land not only alters spatial patterns of rainfall but also produces a pronounced delay in the diurnal cycle of precipitation on islands. The typical late afternoon convective peak shifts toward midnight, a counterintuitive effect linked to reduced solar heating during the day and subsequent nocturnal buildup of moist static energy. This temporal displacement carries significant implications for urban planning, flood management, and agricultural scheduling across densely populated zones like Jakarta and Manila, where timing of rainfall critically influences human activities and infrastructure resilience.
These aerosol effects observed through model simulations find strong corroboration in satellite data, validating the real-world significance of the mechanisms identified. Seasonal haze episodes in the Maritime Continent, often associated with regional biomass burning and industrial emissions, display similar rainfall redistribution patterns. This congruence between theory, simulation, and observation underscores the transformative potential of integrating aerosol dynamics into operational weather and climate prediction frameworks.
Beyond immediate regional impacts, the research carries profound implications for understanding and forecasting tropical atmospheric phenomena more broadly. The Maritime Continent is a critical choke point for the Madden-Julian Oscillation, which modulates weather patterns from Indian monsoons to Pacific typhoons. By elucidating how aerosols weaken land convection and modify ocean-land precipitation contrasts, the study suggests smoother MJO propagation over this region, potentially enhancing the predictability of seasonal climate variability. Such progress promises far-reaching benefits for climate risk management across Asia and beyond.
The realization that aerosol emissions can substantially rewrite precipitation geography compels a reexamination of climate models’ treatment of particulate matter. Integrating these aerosol effects with granularity will refine projections of extreme precipitation, monsoon variability, and tropical cyclone activity under future emission scenarios. Given the escalating urbanization and industrialization in Southeast Asia, this knowledge serves as a critical foundation for devising adaptive strategies against climate-induced water insecurity and disaster risk.
Professor Seo’s findings arrive at a pivotal moment when many tropical regions face mounting challenges posed by air pollution and erratic rainfall. The insights enable more precise short-term forecasting during haze episodes, allowing authorities to better orchestrate emergency responses, manage water resources prudently, and safeguard transportation and infrastructure. Furthermore, the nuanced understanding of aerosol-rainfall interactions informs public health assessments linked to air quality and hydrological variability, spotlighting the interconnectedness of atmospheric chemistry and climate dynamics.
As aerosol concentrations continue to fluctuate due to anthropogenic activity and natural events, the dynamic coupling between aerosols and tropical precipitation highlighted by this research underscores the complexity of Earth’s climate system. It elevates the urgency of incorporating multi-scale, multi-physics aerosol processes into next-generation climate and weather models to capture emergent properties vital for regional climate resilience. Ultimately, the findings herald a transformative shift in how scientists and policymakers approach tropical rainfall forecasting and adaptation in an increasingly aerosol-impacted world.
This pioneering study, published in the reputable journal npj Climate and Atmospheric Science, exemplifies the power of integrating detailed computational modeling with extensive observational datasets to unravel intricate climate processes. The Maritime Continent’s climate regime, intricately tied to global circulation and regional livelihoods, will benefit immensely from these research advances, potentially informing policies that mitigate risks and harness opportunities in a rapidly changing atmosphere.
Subject of Research: Aerosol impacts on regional precipitation patterns over the Maritime Continent, specifically oceanic intensification and diurnal cycle delay of rainfall due to aerosol-induced radiative effects.
Article Title: Aerosol effects on Maritime Continent precipitation: Oceanic intensification and land diurnal cycle delay
News Publication Date: September 25, 2025
Web References:
https://www.nature.com/articles/s41612-025-01215-5
References:
DOI: 10.1038/s41612-025-01215-5
Image Credits:
Professor Kyong-Hwan Seo, Pusan National University, Korea
Keywords:
Environmental sciences, Environmental issues, Environmental monitoring, Pollution, Rain, Air pollution, Atmospheric science, Meteorology
