Circling in on Convective Self-Aggregation
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Circling in on Convective Self-Aggregation. / Nissen, Silas Boye; Härter, Jan Olaf Mirko.
In: Journal of Geophysical Research: Atmospheres, Vol. 126, No. 20, e2021JD035331, 24.09.2021.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Circling in on Convective Self-Aggregation
AU - Nissen, Silas Boye
AU - Härter, Jan Olaf Mirko
PY - 2021/9/24
Y1 - 2021/9/24
N2 - In radiative-convective equilibrium simulations, convective self-aggregation (CSA) is the spontaneous organization into segregated cloudy and cloud-free regions. Evidence exists for how CSA is stabilized, but how it arises favorably on large domains is not settled. Using large-eddy simulations, we link the spatial organization emerging from the interaction of cold pools (CPs) to CSA. We systematically weaken simulated rain evaporation to reduce maximal CP radii, R_{max}, and find reducing R_{max} causes CSA to occur earlier. We further identify a typical rain cell generation time and a minimum radius, R_{min}, around a given rain cell, within which the formation of subsequent rain cells is suppressed. Incorporating R_{min} and R_{max}, we propose a toy model that captures how CSA arises earlier on large domains: when two CPs of radii r_i,r_j ∈ [R_{min}, R_{max}] collide, they form a new convective event. These findings imply that interactions between CPs may explain the initial stages of CSA.
AB - In radiative-convective equilibrium simulations, convective self-aggregation (CSA) is the spontaneous organization into segregated cloudy and cloud-free regions. Evidence exists for how CSA is stabilized, but how it arises favorably on large domains is not settled. Using large-eddy simulations, we link the spatial organization emerging from the interaction of cold pools (CPs) to CSA. We systematically weaken simulated rain evaporation to reduce maximal CP radii, R_{max}, and find reducing R_{max} causes CSA to occur earlier. We further identify a typical rain cell generation time and a minimum radius, R_{min}, around a given rain cell, within which the formation of subsequent rain cells is suppressed. Incorporating R_{min} and R_{max}, we propose a toy model that captures how CSA arises earlier on large domains: when two CPs of radii r_i,r_j ∈ [R_{min}, R_{max}] collide, they form a new convective event. These findings imply that interactions between CPs may explain the initial stages of CSA.
U2 - 10.1029/2021JD035331
DO - 10.1029/2021JD035331
M3 - Journal article
VL - 126
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
SN - 0148-0227
IS - 20
M1 - e2021JD035331
ER -
ID: 281669956