Project purpose/Why Argentina?


RELAMPAGO-CACTI will study a region that has some of the world’s most intense thunderstorms, both in terms of their vertical structure, horizontal size, lightning and hail production, and flooding hazards.  These storms impact the region of the greater La Plata River basin, which has a population of approximately 160,000,000, however they are poorly understood and predicted.  Understanding the processes that lead to these extreme thunderstorms, which produce strong winds, tornadoes, damaging hail, and flooding, will not only benefit countries in South America, but will also benefit our scientific knowledge on extreme thunderstorms that impact other parts of the world (including the US Great Plains), and improve weather and climate models, which poorly represent these systems and their effects.

Figure: Most extreme 1% TRMM precipitation feature (PF) values for (a) minimum 37-GHz PCT (low values signifying hailstorms) and (b) lightning flash rate in each category for each 2° latitude × 2° longitude box with boxes containing less than 150 PFs left blank (adapted from Zipser et al. 2006); frequency of occurrence of strong (c) deep convective cores (DCCs; 40 dBZ > 10 km in height) and (d) wide convective cores (WCCs; 40 dBZ > 1,000 km^2 in horizontal area) in the summer in both hemispheres (JJA – Northern Hemisphere; DJF – Southern Hemisphere) from TRMM PR observations where (adapted from Houze et al. 2015). The SESA region is outlined in red.

RELAMPAGO will leverage the large DOE project (CACTI; ~$7.4M) and significant contributions from Argentina, Brazil, and Chile, in the setting in the lee of the Andes, to address the following grand hypothesis:

The meteorological-geographical setting in the lee of the Andes Cordillera, including multi-scale interactions of synoptic disturbances, the South American Low Level Jet (SALLJ), and the complex terrain characteristics produce unique kinematic, thermodynamic, and aerosol environments that serve as controlling mechanisms for convective initiation, intensification, and upscale growth. These factors contribute to a unique convective spectrum that governs high impact weather in South America. Intensive field observations and characterization of these physical mechanisms will yield new understanding of relationships between convective systems and the environment, and therefore improve the prediction of convection globally.

RELAMPAGO will study storms in two locations that repeatedly initiate, grow, and produce high impact weather (hail, tornadoes, flooding): near the Sierras de Córdoba and near Mendoza, where convective mode, and severe weather/hydrometeorological impacts are different. RELAMPAGO will have a large impact on understanding convective storms and high impact weather, and will provide for new scientific connections and Education and Public Outreach between the US and many Latin American countries.