DYNAMICS OF SHALLOW TO DEEP CONVECTION TRANSITIONS: A STUDY FROM THE SIERRAS DE CÓRDOBA, ARGENTINA
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Authors
Bazemore, Daniel W.
Subjects
convection
deep convection
convective updrafts
effective buoyancy
pressure gradient acceleration
dilution
vertical velocity
convergence
Cloud Model 1
CACTI
updraft dynamics
deep convection
convective updrafts
effective buoyancy
pressure gradient acceleration
dilution
vertical velocity
convergence
Cloud Model 1
CACTI
updraft dynamics
Advisors
Nuss, Wendell A.
Radko, Timour
Montgomery, Michael T.
Powell, Scott
Witte, Mikael
Mulholland, Jake, University of North Dakota
Date of Issue
2024-09
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
This dissertation investigates the dynamics of shallow to deep convective transitions over complex terrain, focusing on the Sierras de Córdoba in Argentina. Using simulations initialized using observations from the Cloud, Aerosol, and Complex Terrain Interaction (CACTI) experiment, this study explores how sufficient low-level moisture, reduced low-level horizontal wind shear, and initial updraft size impact convective development. Semi-realistic simulations conducted with Cloud Model 1 include realistic terrain and enable Lagrangian analysis of cloudy updraft dynamics, linking terrain-driven convergence, updraft size, and in-cloud dilution. Key findings reveal that deeply ascending parcels experienced less dilution because they were farther from the edge of a cloud and therefore more protected from mixing with dry, non-cloudy air. Additionally, shallow convection appeared to deposit moisture into the free troposphere, facilitating subsequent deep convection just a few hours later. The study also examines the complex relationship between convergence and updraft size, suggesting that while terrain-induced convergence might support more robust updrafts, its exact influence requires further investigation. These insights contribute to a deeper understanding of convective dynamics in terrain-influenced environments, offering implications for improving weather prediction models and parameterization schemes.
Type
Thesis
Description
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NPS Report Number
Sponsors
Department of Energy
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Citation
Distribution Statement
Distribution Statement A. Approved for public release: Distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.