The ARM Mobile Facility

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The ARM Mobile Facility

• Mark Miller
• Team Mary Jane Bartholomew, Larry Jones, Kim
  Nitschke, Doug Sisterson
• Chief Engineer Kevin Widener

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MASRAD

• MArine Stratus Radiation, Aerosol, and Drizzle
  (MASRAD)Multiple ARM PIs
• DOE Atmospheric Science Program Pete Daum (BNL),
  John Ogren (CMDL) and others
• Office of Naval Research John Seinfeld (Caltech)
• Anthony Wexler (UC Davis)
• Scientific Objectives
• (1) Investigate the general relationship between
  cloud liquid water structure, aerosols, cloud
  microphysics, drizzle and radiation in marine
  stratus clouds
• (2) Investigate the aerosol effects on the amount
  of solar radiation absorbed by marine stratus
  clouds

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Pt. Reyes National Seashore

• Coastal Northern California

San Francisco
Monterey
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Site
Pt. Reyes Light
Wind
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Conditions

• 5.5 months duration
• Low cloud bases and frequent fog
• Predominantly marine air masses
• HYSPLIT
• MJ Bartholomew

M. Dunn / BNL
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Systematic Variation of Aerosol Optical
Properties
Pt Reyes
Backscatter fraction
Single scattering albedo
Pt Reyes
Scattering Coefficient (Mm-1) aerosol
cross-sectional area for scattering for a unit
volume of air (10-6 m-1 1M m-1)
From Delene and Ogren, 2000 Courtesy of E.
Andrews and J. Ogren
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Whatd we see? Aerosol scattering and absorption
Sub 5um Sub 1um
July
The large difference in scattering between
sub5-um and sub1-um aerosol is likely due to sea
salt.
Scattering (Mm-1)
Bond et al., 1999 standard correction for
scattering may be too large for sea salt
dominated aerosol.
Absorption (Mm-1)
Courtesy of E. Andrews and J. Ogren
DOY, 2005 (100 April 10)
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Cloud Droplet Nucleation
Number of Cloud Droplets

• Aerosols have different
• Sizes
• Nucleation properties

• Cloud Condensation Nuclei (CCN) Activation
  Spectrum
• Number CCN activated as a function of
  supersaturation

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In-cloud Vertical Velocity
M. Dunn/BNL
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Cloud Droplet Nucleation

• Cloud Condensation Nuclei (CCN) activity spectrum
  measured continuously
• See our poster

Observed Range of Updrafts
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RADAGAST

• Radiative Divergence using AMF, GERB, and AMMA
  Stations
• Tony Slingo, PI
• Niamey, Niger Jan-Dec 2006
• Operational
• Broadband Heating Rate Profile
• GERBGeostationary Broadband sensor on METEOSAT8

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Niger
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Micropulse Lidar
Cloud Droplets
Cloud and/or Aerosol
Southwest Winds
Negligible Return
North Winds
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Cloud Droplets
Cloud and/or Aerosol
Negligible Return
0000
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Summary of Winter Conditions

• Decoupling
• Multiple stacked mixed layers
• Frequent cirrus
• Thin liquid clouds at the freezing level
• Major dust storm

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Courtesy of Ben Mohammed
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V4500m
Courtesy of Ben Mohammed
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Courtesy of Ben Mohammed
V700m, Mass Concentration1,700mg m-3
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March 8-11 Dust Storm
Total Irradiance
Diffuse 800 Wm-2
Direct Normal
Diffuse
Direct Normallt200 Wm-2!!
Source Data Quality Office
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Dust product (upper) and GERB OLR (lower) for
1200UT on 8 March 2006
Courtesy of Anthony Slingo
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March 9
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Cloud Droplets
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Cloud and/or Aerosol
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Height (km)
5
Negligible Return
0
1200
0000
0000
Time (UTC)
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500 nm RV Ron Brown Central Pacific AOT0.08
AMF Niamey, Niger AOT2.5-3
Sea of Japan AOT0.98
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3.2 mm Cloud Radar in Niamey
Courtesy of Kevin Widener
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(No Transcript)
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Summary
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Cloud Liquid Water Path (LWP)

• Low LWPs problematic
• AERI-MWR combination promising

AERI MWR MWR Physical MWR Stat2 Original MWR
Consensus At LWPgt50 MWR only
Negative LWPs
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Data Status

• Low cloud base and extremely low cloud liquid
  water
• 3.2 mm cloud radar (WACR) and Microwave
  Radiometer (MWR) operating at edge of capability
• MWR
• Dave Turner testing algorithms
• WACR
• Artifacts
• Doppler Velocity algorithm development (P.
  Kollias and M. Dunn)
• Reflectivity not yet addressed