Cold Pools as Conveyor Belts of Moisture

Observations and simulations have found convective cold pools to trigger and organize subsequent updrafts by modifying near-surface temperature and moisture as well as by lifting air parcels at the outflow boundaries. We study the causality between cold pools and subsequent deep convection in an ide...

Full description

Saved in:
Bibliographic Details
Published inEarth and Space Science Open Archive ESSOAr
Main Authors Fuglestvedt, Herman F, Haerter, Haerter O
Format Paper
LanguageEnglish
Published Washington American Geophysical Union 28.02.2020
Subjects
Air parcels
Air temperature
Atmospheric convection
Belt conveyors
Boundaries
Cold
Cold pools
Convection
Convergence
Fluxes
Funnels
Large eddy simulation
Large eddy simulations
Moisture
Outflow
Pools
Surface fluxes
Surface temperature
Updraft
Online AccessGet full text

Cover

More Information
Summary:Observations and simulations have found convective cold pools to trigger and organize subsequent updrafts by modifying near-surface temperature and moisture as well as by lifting air parcels at the outflow boundaries. We study the causality between cold pools and subsequent deep convection in an idealized large-eddy simulation by tracking colliding outflow boundaries preceding hundreds of deep convection events. When outflow boundaries collide, their common front position remains immobile, whereas the internal cold pool dynamics continues for hours. We analyze how this dynamics "funnels" moisture from a relatively large volume into a narrow convergence zone. We quantify moisture convergence and separate the contribution from surface fluxes, finding that it plays a secondary role. Our results highlight that dynamical effects are crucial in triggering new convection, even in radiative-convective equilibrium. However, it is the moisture convergence resulting from this dynamics that moistens the atmosphere aloft and ultimately permits deep convection.
DOI:10.1002/essoar.10502398.1