Utilizing a storm-generating hotspot to study convective cloud transitions: The CACTI experiment

Adam C. Varble, Stephen W. Nesbitt, Paola Salio, Joseph C. Hardin, Nitin Bharadwaj, Paloma Borque, Paul J. DeMott, Zhe Feng, Thomas C.J. Hill, James N. Marquis, Alyssa Matthews, Fan Mei, Rusen Öktem, Vagner Castro, Lexie Goldberger, Alexis Hunzinger, Kevin R. Barry, Sonia M. Kreidenweis, Greg M. McFarquhar, Lynn A. McMurdieMikhail Pekour, Heath Powers, David M. Romps, Celeste Saulo, Beat Schmid, Jason M. Tomlinson, Susan C. van den Heever, Alla Zelenyuk, Zhixiao Zhang, Edward J. Zipser

Research output: Contribution to journalReview articlepeer-review


The Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign was designed to improve understanding of orographic cloud life cycles in relation to surrounding atmospheric thermodynamic, flow, and aerosol conditions. The deployment to the Sierras de Córdoba range in north-central Argentina was chosen because of very frequent cumulus congestus, deep convection initiation, and mesoscale convective organization uniquely observable from a fixed site. The C-band Scanning Atmospheric Radiation Measurement (ARM) Precipitation Radar was deployed for the first time with over 50 ARM Mobile Facility atmospheric state, surface, aerosol, radiation, cloud, and precipitation instruments between October 2018 and April 2019. An intensive observing period (IOP) coincident with the RELAMPAGO field campaign was held between 1 November and 15 December during which 22 flights were performed by the ARM Gulfstream-1 aircraft. A multitude of atmospheric processes and cloud conditions were observed over the 7-month campaign, including numerous orographic cumulus and stratocumulus events; new particle formation and growth producing high aerosol concentrations; drizzle formation in fog and shallow liquid clouds; very low aerosol conditions following wet deposition in heavy rainfall; initiation of ice in congestus clouds across a range of temperatures; extreme deep convection reaching 21-km altitudes; and organization of intense, hail-containing supercells and mesoscale convective systems. These comprehensive datasets include many of the first ever collected in this region and provide new opportunities to study orographic cloud evolution and interactions with meteorological conditions, aerosols, surface conditions, and radiation in mountainous terrain.

Original languageEnglish (US)
Pages (from-to)E1597-E1620
JournalBulletin of the American Meteorological Society
Issue number8
StatePublished - Aug 2021


  • Aerosol-cloud interaction
  • Aerosols/particulates
  • Aircraft observations
  • Atmospheric
  • Boundary layer
  • Clouds
  • Complex terrain
  • Convective clouds
  • Convective storms
  • Convective-scale processes
  • Cumulus clouds
  • Deep convection
  • Diurnal effects
  • Drizzle
  • Extreme events
  • Field experiments
  • Fog
  • Hail
  • In situ atmospheric observations
  • Instability
  • Instrumentation/sensors
  • Lidars/Lidar observations
  • Longwave radiation
  • Measurements
  • Mesoscale processes
  • Mesoscale systems
  • Microwave observations
  • Mountain meteorology
  • Orographic effects
  • Precipitation
  • Profilers
  • Radars/Radar observations
  • Radiative fluxes
  • Radiosonde/rawinsonde observations
  • Rainfall
  • Remote sensing
  • Satellite observations
  • Severe storms
  • Shortwave radiation
  • Soil moisture
  • Soil temperature
  • Soundings
  • South America
  • Southern Hemisphere
  • Storm environments
  • Stratiform clouds
  • Subseasonal variability
  • Supercells
  • Surface fluxes
  • Surface observations
  • Thunderstorms
  • Topographic effects
  • Valley/mountain flows
  • Wind profilers
  • Wind shear

ASJC Scopus subject areas

  • Atmospheric Science


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