PACS STRATUS 2003
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Transcript of PACS STRATUS 2003
Preliminary Results from Stratus 03 Cruise on R/V Revelle
Fairall, Zuidema, Hare, Kollias, TomlinsonWCRP/CLIVAR/VAMOS Panel Meeting 7
Guayaquil, EcuadorMarch 2004
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
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 in
inversion/cloud-top height weaker?• SSTs ~ 1K warmer; cloudbase higher
Aerosol measurements taken (new) but no C-band radar
Observation Systems
Climate Reference Buoy Cloud Radar and Microwave Radiometer
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
BL winds from SE, above-BL-winds more variable (synoptics?)
Both virtual potential temperature and LCL show influence of drizzle
85W, 20S: Inversion less developed in Nov. 2003 than Oct. 2001Boundary layer warmer ~ 1.5K, higher moisture content, less RH
PACS03
EPIC01
RH TT
v e
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Clouds at buoy thin compared to the rest of the cruise (and to EPIC 2001)
Chris Fairall’s simple aerosol counter compares well to Don Collins’ aerosol measurements (r>0.1 micron)
Aerosol indirect effectWithin well-mixed non-precipitating clouds, expect
lnr/lnN = 0.3 sometimes it’s there, sometimes not
What is the relationship between drizzle, aerosol, and liquid water path ?
As well as surface fluxes….
Comparison of Cloud Diurnal Cycle:Epic2001 vs Stratus2003