New observations of clouds, atmosphere,

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ICECAPS
New observations of clouds, atmosphere,
and precipitation at Summit, Greenland
Matthew Shupe, Von Walden, David Turner Ryan
Neely, Ben Castellani, Chris Cox, Penny Rowe,
Nate Miller, Maria Cadeddu
Special thanks to a large team of supporters and
collaborators
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How do clouds impact the Greenland Ice
Sheet? Source Precipitation gt The Mass
Budget Sink Radiation gt The Energy Budget
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Introducing the Mobile Science Facility at Summit
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Microwave Radiometers PWV, LWP, T
Sodar Boundary layer depth
Precip Sensor Rate, PSD?
Ceilometer Cloud base
Cloud Radar Cloud macrophysics, phase,
microphysics, dynamics
Depolarization Lidars Cloud base, phase,
microphysics, orientation
Radiosonde T, RH
Spectral Infrared Interferometer Cloud phase,
microphysics, LW radiation, trace gases
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Continuous radiosonde measurements
Signs of spring?
Tropopause height
Cold and dry
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Thermodynamic profiles and clouds

• Surface-based T and q inversions at 100-300m
  (almost always present)
• Atmosphere is relatively moist warm with clouds
  (15 C warmer, 4x moister)
• Need to distinguish impacts of clouds vs. water
  vapor on SEB w/ season

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Cloud Roses

• Cloud presence/depth determined by multi-sensor
  analysis
• 90 of SE flow is cloudy, frequent clouds in flow
  from 100-300
• With winds, almost all clouds come from SW-S

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Precipitation Roses

• Precipitation occurrence identified by
  ground-based radar
• Frequent precipitation in W flow
• Very little precipitation coming from N sector
  flows, most from SW.

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Summit clouds compared to other Arctic locations

• Generally Remarkable similarity with other
  locations

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Summit clouds compared to other Arctic locations

• LWP derived from microwave radiometer brightness
  temperatures
• Most Arctic clouds are thin ( LWP lt 50 g/m2)
• Thick clouds are virtually non-existent at
  Summit

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Detailed cloud microphysical-dynamical relations
are also similar
q
qE
High reflectivity high depol ice
precip
Velocity variability
High backscatter low depol liquid
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Detailed cloud microphysical-dynamical relations
are similar!
Cloud mixed-layer
Cloud-generated turbulence
Cloud ice nucleates in liquid
W-LWP-IWP correlation
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Ice Precip, Crystal Habits

• Mixed-phase environment w/ riming
• Ttop -20 C
• Dendrites form around -15 C and generally above
  water saturation
• Plates, sector plates in same T range but do not
  need water saturation

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Ice Precip, Crystal Habits

• Ice cloud. Poss. liquid near sfc.
• T -40 to -18 C
• Bullets, hollow capped columns, assemblages of
  plates/side planes (all -20 to -30 C, Magono and
  Lee)

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• Summary
• New cloud-atmosphere observing capabilities at
  Summit, Greenland
• Many cloud characteristics are similar to
  elsewhere in the Arctic
• Good opportunities to study cloud interactions
  with meteorology, boundary layer, surface energy
  budget, and precipitation
• We welcome collaborations!