Department of Environmental Sciences
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Seminar Abstracts
Environmental Sciences Seminar Abstract            

  Understanding Controls on Tropical Convective Margins and Their Variability
Benjamin Lintner
University of California, Los Angeles

As transition zones between strongly-convecting and nonconvecting regimes, the near-edge environments of tropical convection zones-or convective margins-are subject to significant variability across many timescales. The sensitivity of tropical convective margins to climate perturbations, including projected anthropogenic climate change, underscores the need to understand the interplay of dynamics and thermodynamics controlling convective margin variability. Here, a theoretical prototype is developed to identify the factors that influence those convective margins in which there is substantial low-level inflow from an adjacent dry region into the convection zone. The prototype clearly demonstrates the relationships among inflow air mass moisture, air mass modification along the inflow trajectory by convergence and evaporation, and the ~Sthreshold~T moisture at which deep convection can occur. As illustrations of its utility, the inflow prototype is applied to analysis of regional El NiƱouthern Oscillation (ENSO) precipitation teleconnections over equatorial South America, high-frequency inflow-moisture-precipitation relationships along the South Pacific and South Atlantic Convergence Zones, and land-atmosphere interactions. The relevance of the convective margins framework to model diagnosis, bias mitigation, and intercomparison is also discussed.


Last updated: 03/02/2009