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Abstract
Charging of upper and lower horizontal boundaries of extensive layer‐clouds results from current flow in the global electric circuit. Layer‐cloud charge accumulation has previously been considered a solely electrostatic phenomenon, but it does not occur in isolation from meteorological processes, which can transport charge. Thin layer‐clouds provide special circumstances for investigating this dynamical charge transport, as disruption at the cloud‐top may reach the cloud base, observable from the surface. Here, a thin (∼300 m) persistent layer‐cloud with base at 300 m and strong wind shear at cloud‐top was observed to generate strongly correlated fluctuations in cloud base height, optical thickness and surface electric Potential Gradient (PG) beneath. PG changes are identified to precede the cloud base fluctuations by 2 min, consistent with shear‐induced cloud‐top electrical changes followed by cloud base changes. These observations demonstrate, for the first time, dynamically driven modification of charge within a layer‐cloud. Even in weakly charged layer‐clouds, redistribution of charge will modify local electric fields within the cloud and the collisional behaviour of interacting charged cloud droplets. Local field intensification may also explain previously observed electrostatic discharges in warm clouds.
Original language | English |
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Pages (from-to) | 3667-3679 |
Number of pages | 13 |
Journal | Quarterly Journal of the Royal Meteorological Society |
Volume | 145 |
Issue number | 725 |
Early online date | 26 Aug 2019 |
DOIs | |
Publication status | Published - 1 Oct 2019 |
Keywords
- Kelvin–Helmholtz billows
- atmospheric electricity
- cloud microphysics
- stratiform cloud
ASJC Scopus subject areas
- Atmospheric Science
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Dive into the research topics of 'Shear-induced electrical changes in the base of thin layer-cloud'. Together they form a unique fingerprint.Projects
- 1 Finished
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Understanding Energetic Particle Effects on Atmospheric Processes
Nicoll, K. (PI)
Natural Environment Research Council
1/03/16 → 30/09/20
Project: Research council