Vaughan Phillips
Universitetslektor
Dependencies of Four Mechanisms of Secondary Ice Production on Cloud-Top Temperature in a Continental Convective Storm
Författare
Summary, in English
Various mechanisms of secondary ice production (SIP) cause multiplication of numbers of ice particle, after the onset of primary ice. A measure of SIP is the ice enhancement ratio (“IE ratio”) defined here as the ratio between number concentrations of total ice (excluding homogeneously nucleated ice) and active ice-nucleating particles (INPs). A convective line observed on 11 May 2011 over the Southern Great Plains in the Mesoscale Continental Convective Cloud Experiment (MC3E) campaign was simulated with the “Aerosol–Cloud” (AC) model. AC is validated against coincident MC3E observations by aircraft, ground-based instruments, and satellite. Four SIP mechanisms are represented in AC: the Hallett–Mossop (HM) process of rime splintering, and fragmentation during ice–ice collisions, raindrop freezing, and sublimation. The vertical profile of the IE ratio, averaged over the entire simulation, is almost uniform (102 to 103) because fragmentation in ice–ice collisions dominates at long time scales, driving the ice concentration toward a theoretical maximum. The IE ratio increases with both the updraft (HM process, fragmentation during raindrop freezing, and ice–ice collisions) and downdraft speed (fragmentation during ice–ice collisions and sublimation). As reported historically in aircraft sampling, IE ratios were predicted to peak near 103 for cloud-top temperatures close to the −12°C level, mostly due to the HM process in typically young clouds with their age less than 15 min. At higher altitudes with temperatures of −20° to −30°C, the predicted IE ratios were smaller, ranging from 10 to 102, and mainly resulted from fragmentation in ice–ice collisions.
Avdelning/ar
- Institutionen för naturgeografi och ekosystemvetenskap
- MERGE: ModElling the Regional and Global Earth system
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- eSSENCE: The e-Science Collaboration
Publiceringsår
2022-12-05
Språk
Engelska
Sidor
3375-3404
Publikation/Tidskrift/Serie
Journal of Atmospheric Sciences
Volym
79
Issue
12
Dokumenttyp
Artikel i tidskrift
Förlag
Amer Meteorological Soc
Ämne
- Meteorology and Atmospheric Sciences
Status
Published
Projekt
- Mechanisms for the Ice Nucleus Aerosols and their Indirect Effects: Cloud Modelling
- Secondary ice production in simulated cloud-types
- Mechanisms for the Influence from Ice Nucleus Aerosols on Clouds and their Indirect Effects: Cloud Modelling
ISBN/ISSN/Övrigt
- ISSN: 1520-0469