UPDRAFT FORCING MECHANISMS IN DEEP MARINE CONVECTION DRIVEN BY COLD POOLS
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Authors
Wasserman, Jessica B.
Subjects
cold pool
CALICO
updraft radius
LCL
CM1
LES
convection
buoyancy
wind shear
relative humidity
CALICO
updraft radius
LCL
CM1
LES
convection
buoyancy
wind shear
relative humidity
Advisors
Powell, Scott
Date of Issue
2024-03
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Aircraft and rawinsonde data collected during the CALifornia Investigation of Convection over Ocean (CALICO) field experiment between February and March of 2022 were analyzed to detail the size and magnitude of in-cloud cumuliform updrafts. Sampled convection generally occurred following wintertime cold-front passages off the central California coast, with much of the convection growing to the 6 km high tropopause and organizing into “arcs” driven by cold pools. Large-eddy simulations using Cloud Model 1 (CM1) were conducted to augment observations and characterize the three-dimensional cloud properties within cold-pool-driven convection to subsequently investigate what processes (both thermodynamic and dynamic) within the atmospheric boundary layer and free troposphere control the upward acceleration of negatively buoyant updrafts located behind a cold pool boundary. The effect of vertical wind shear on isolated and organized mesoscale convection is simulated. Organized convection is able to reach the tropopause despite the presence of strong vertical wind shear that inhibits isolated convection. Within the cold pool, the presence of negative buoyant but ascending updrafts was due to the presence of small pockets of strong upward acceleration caused by an upward-oriented pressure gradient force associated with the dynamic perturbation pressure.
Type
Thesis
Description
Series/Report No
Department
Meteorology (MR)
Organization
Identifiers
NPS Report Number
Sponsors
Office of Naval Research
Funder
Format
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.