Mingyue Tang's Research

Rethinking Offshore Propagation of Tropical Convection

Schematic of breeze, cold pool, and offshore convection interactions

How can thunderstorms born over tropical mountains vanish near the coast, only to reappear hours later over the open ocean and continue traveling for hundreds of kilometers? For decades, this remarkable offshore propagation has often been viewed as a single, continuous journey. My research suggests a very different picture. Rather than one uninterrupted convective system, offshore propagation over New Guinea unfolds as a two-stage relay: a land mode, in which afternoon convection develops over the mountain slopes and propagates toward the coast, and an ocean mode, in which convection regenerates over the warm ocean after sunset. This distinction helps connect the familiar double peak of tropical island rainfall–one over land and another offshore at night–to two physically distinct propagation processes. It also changes the central question from how storms keep moving continuously to how one convective mode gives way to another.

This reframing requires a different way of thinking about the coastal flows that organize tropical convection. In this work, I reinterpret sea breezes and land breezes not merely as daily wind reversals, but as coastal density currents with distinct structures, asymmetries, and interactions with convective outflows. The sea breeze is not simply the daytime counterpart of the land breeze: it can interrupt the land mode by carrying cool marine air inland, while the nocturnal land breeze behaves as a shallow offshore density current capable of merging directly with storm-generated cold pools. This interaction produces what I call a hybrid land breeze–a cold-pool-enhanced nocturnal density current that couples with moist boundary-layer thermodynamics, organizes moist patches along its leading edge, supports convective regeneration over the ocean, and helps transform a local diurnal circulation into a mechanism for long-distance offshore propagation.

This study also introduces a novel two-and-a-half-variable framework that identifies the spatial relationship between old and newly developing convective cells and tracks how cold pools connect them directly from high-resolution simulations, extending my previous diagnostic work while avoiding computationally expensive Lagrangian particle tracking. It assesses whether hybrid land breezes exhibit density-current characteristics and contain embedded cold-pool components as well.

More broadly, this work emphasizes the nonlinear processes that emerge after convective initiation. Once storms form, their cold pools, moist patches, and gust fronts actively reshape the boundary layer, influencing where convection regenerates and how long it remains organized over the ocean. From this small-scale perspective, tropical offshore propagation becomes a cross-scale interaction problem in which convective-scale cold pools, island-scale land-sea breezes, and the lower-tropospheric cross-equatorial monsoon interact within the moist tropical boundary layer. Together, these processes suggest that tropical offshore propagation is best understood not as the evolution of an individual storm, but as an emergent phenomenon arising from interactions across convective, island, and monsoon scales. For more details, check our recent publication Tang et al. (2025). For a more accessible analogy, see this plain-language explanation of the storm relay from the mountains to the deep ocean.

Schematic of monsoon influence and hybrid land breeze offshore propagation

Convective Organization & Propagation

This one-hour simulation from the System for Atmospheric Modeling (SAM) shows how short-lived individual clouds can collectively form a much longer-lived convective system. New clouds initiate near the surface, grow into deep convection, propagate across the periodic domain, and decay into upper-level stratiform clouds. Although a single cloud rarely lasts more than half an hour, successive generations of clouds leave behind coherent patterns in space and time.

My research asks how this organization emerges, how it can be quantified, and how organized convection becomes linked to propagation. These questions are central to my Ph.D. dissertation, Mechanistic Understanding of Tropical Convective Organization and Propagation, where I aim to develop a physical understanding of the mechanisms that allow tropical convective systems to organize, persist, and move.

Cold Pools, Moist Rings & Tropical Cloud Organization

Why focus on the tropics? Tropical convection has weaker updrafts, downdrafts, cold pools, and wind shear, and it was thought to be less organized. However, tropical clouds actually show organization at various scales. Why is this? Do cold pools still play a crucial role? These questions require further investigation. Due to the abundant moisture in the tropics, the evaporative cooling that forms cold pools may not be as strong. However, because of the thermodynamic effects of this moisture, the mature cold pool edges may form moist rings (moist patches) that help generate new convective clouds and organize convective systems. To uncover these secrets, please check our recent publication Tang et al., 2024!

Lagrangian Particle Dispersion Model (LPDM)

The evolution of various properties makes it difficult to separate cold pools, define their sizes, and determine their role in organizing tropical convection. Therefore, we need a new technique, LPDM! Here are some advantages of Lagrangian tracking for understanding cold pools at a process level: highly intuitive as particles naturally follow the downdrafts, allows continuous tracking of particles throughout the entire dispersal process during the cold pool's life cycle, ensures that information carried by particles remains unaffected by the collision between cold pools or the disintegration of dry-cooled areas, and establishes a more straightforward connection with convective parameterizations.

Madden-Julian Oscillation (MJO)

The Madden‐Julian Oscillation (MJO) is a tropical eastward-propagating disturbance that originates in the Indian Ocean and repeats for 30–90 days. The MJO has been shown to influence weather and climate phenomena worldwide, but the theories of its propagation and initiation are still under debate, and far less understood than ENSO's. The envelope of the MJO is composed of mesoscale convective systems (MCSs), which in turn are made of individual clouds that organize across space and time. My research focuses on the cloud dynamics in two critical areas for MJO: 1. Central Indian Ocean, where MJO initiates; 2. Maritime Continent, which may break down MJO as a barrier effect.