Cumulus clouds

Cumulus

What do Cu tell us?

• What can we deduce about the state of the atmosphere from:– The presence of Cu?– The nature of the Cu?

• What other observations can help supplement and complement our knowledge of Cu and how?

What do Cu tell us?

• About stability

• About moisture

• About the wind

• About anything else

Cu Development

• From boundary layer forcing (warming)

• Often over warm water

• Little wind shear

• Growth occurs downstream with increased forcing and boundary layer depth

Open and closed cells and the jetstream

Jet stream position

• Closed cell Cu form from radiative cooling at top of boundary layer, resulting in darker cooler clouds

• Division between open and closed cells can indicate position of the jetstream (a little poleward of the boundary)

Conceptual diagram 1

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