PACS STRATUS 2003

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PACS STRATUS 2003

• left Manta Ecuador, went to 85W line, traveled
  south to 20S
• stayed at WHOI buoy from Nov. 15 21 (12 UTC)
• traveled east along 20S to Arica Chile
• data taken Nov. 13 Nov. 24

Aerosol measurements taken (new) but no C-band
radar

• Differences from the (October) EPIC 2001 cruise
• fewer thinner clouds less drizzle,
• particularly at the buoy (now at stratus deck
  edge)
• diurnal cycle in large-scale subsidence not
• apparent in inversion/cloud-top height
• SSTs 1K warmer

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Above-BL moisture appears to subside into the BL,
separated by 4 days, coinciding with a rising
cloud top and drizzle at surface (JD 324).
Pink indicates radar-derived cloud top
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BL winds from SE, above-BL-winds more variable
(synoptics?)
Both virtual potential temperature and LCL show
influence of drizzle
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85W, 20S Inversion less developed in Nov. 2003
than Oct. 2001 Boundary layer warmer 1.5K,
higher moisture content, less RH
RH
T
T
q
q
q
v
e
PACS03
q
EPIC01
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Clouds at buoy thin compared to the rest of the
cruise (and to EPIC 2001)
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Chris Fairalls simple aerosol counter compares
well to Don Collins aerosol measurements (rgt0.1
micron)
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Aerosol indirect effectWithin well-mixed
non-precipitating clouds, expect -dlnr/dlnN 0.3
sometimes its there,
sometimes not
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What is the relationship between drizzle,
aerosol, and liquid water path ?
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As well as surface fluxes.