About the project
Warm weather episodes and, consequently, a significant portion of the rainfall in the southernmost regions of South America and Antarctica are attributed to warm, moist transient weather systems. These systems initiate over the Southern Ocean at lower latitudes, propagate eastward and poleward, and eventually dissipate near the Antarctic continent. When a strong ridge or a blocking pattern develops over the Southern Ocean (at polar latitudes), the cyclones can become stationary for several days. This stationary phase allows them to transport moisture and heat from subtropical or mid-latitude regions to Antarctica, creating highly favorable conditions for the development of atmospheric rivers (ARs). The presence of ARs is associated with strong positive anomalies in temperature and precipitation.
The internal transport processes governing moisture, droplets, and aerosols within AR-related flows remain poorly constrained by observations, especially at the scales where turbulence, vertical shear, and flow unsteadiness coexist. Most existing measurements rely on Eulerian approaches, such as individual radiosoundings and satellite observations, which provide limited information on the actual Lagrangian pathways followed by air parcels and inertial particles. This limitation is particularly pronounced in the Southern Hemisphere, where in-situ observations are sparse.
To address this challenge, the Max Planck Institute for Dynamics and Self-Organization (MPI-DS, Germany) and Argentina’s Servicio Meteorológico Nacional (SMN) are launching the Lagrangian Atmospheric Multisonde Dispersion Analysis - South (LAMDA-S) campaign in Ushuaia, Argentina, the critical gateway between the Southern Ocean and Antarctica. Ushuaia’s strategic location makes it a natural laboratory for studying extreme atmospheric transport, frequently impacted by ARs and strong synoptic variability, yet under-sampled for Lagrangian observations.
The campaign combines two complementary approaches:
- MPI-DS will simultaneously release ten lightweight, biodegradable, instrumented helium balloons simultaneously, tracking them up to 6 km altitude to study small-scale turbulent transport with minimal inertial bias. This experiment will be repeated at least 30 times. This enables direct measurement of particle dispersion, relative motion, and clustering, key to understanding Lagrangian transport.
- SMN will conduct high-resolution meteorological soundings up to 32 km altitude, capturing meso-scale atmospheric dynamics and synoptic conditions.
By integrating these perspectives LAMDA-S will provide a comprehensive view of how local processes influence and are influenced by broader atmospheric flows.
The LAMDA-S campaign builds on prior successes: MPI-DS’s work in the IMPACT campaign (Finland, 2024) and SMN’s T-SCAN campaign (Antarctica, 2025), both focused on turbulence and cloud physics. Together, they bring deep expertise in atmospheric soundings and transport dynamics.
Ultimately, LAMDA-S aims to deliver a unique, high-resolution dataset of Lagrangian trajectories in AR-influenced environments. This will advance fundamental understanding of atmospheric dispersion, improve the interpretation of Eulerian observations, and enhance transport parameterizations in weather and climate models, bridging scales from turbulence to synoptic systems.