Data · dataset · 2026
Impact of entrainment-mixing and turbulent fluctuations on droplet size distributions in a cumulus cloud: An investigation using Lagrangian microphysics with a sub-grid-scale model
Listed in National Center for Atmospheric Research
Entrainment mixing and turbulent fluctuations critically impact cloud droplet size distributions (DSDs) in cumulus clouds.
Description
This problem is investigated via a new sophisticated modeling framework using the Cloud Model 1 (CM1) LES model and a Lagrangian cloud microphysics scheme-the "superdroplet method" (SDM)-coupled with subgrid-scale (SGS) schemes for particle transport and supersaturation fluctuations. This modeling framework is used to simulate a cumulus congestus cloud.
Average DSDs in different cloud regions show broadening from entrainment and secondary cloud droplet activation (activation above the cloud base). DSD width increases with increasing entrainment-induced dilution as expected from past work, except in the most diluted cloud regions. The new modeling framework with SGS transport and supersaturation fluctuations allows a more sophisticated treatment of secondary activation compared to previous studies.
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In these simulations, it contributes about 25% of the cloud droplet population and impacts DSDs in two contrasting ways: narrowing in extremely diluted regions and broadening in relatively less diluted. SGS supersaturation fluctuations contribute significantly to an increase in DSD width via condensation growth and evaporation. Mixing of superdroplets from SGS velocity fluctuations also broadens DSDs.
The relative dispersion (ratio of DSD dispersion and mean radius) negatively correlates with gridscale vertical velocity in updrafts but is positively correlated in downdrafts. The latter is from droplet activation driven by positive SGS supersaturation fluctuations in grid-mean subsaturated conditions. Finally, the sensitivity to model grid length is evaluated.
The SGS schemes have greater influence as the grid length is increased, and they partially compensate for the reduced model resolution.
Links
Get the data
- Publisher page n2t.org/ark:/85065/d7th8r8g ↗
documentation · download · from data ucar edu
Where it is published
- data.ucar.edu /dataset/impact-of-entrainment-mixing-and-turbulent-fluctuation… ↗
National Center for Atmospheric Research dataset page
landing page · from data ucar edu
Catalogue records · 1
- CKAN API data.ucar.edu/api/3/action/package_show?id=a279216d-67ff-41a4-ae9c-04fdc1df0… ↗
metadata API · from data ucar edu
Topics
- From keywords
- Earth & Environmental Science · Ocean & Atmospheric Science
- Inferred from text
- Cloud physics 80%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| National Center for Atmospheric Research | a279216d-67ff-41a4-ae9c-04fdc1df0931 | 9 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[field].anzsrc:field:370107 | enrichment · data ucar edu | taxonomy-embedding@1.1.0 | title+keywords+description (80%) |
| concepts[field].local:field:earth-environmental | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| concepts[field].local:field:ocean-atmospheric | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| created_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| description | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /notes |
| publication_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| title | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /title |
| updated_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 |