Atmospheric boundary layer research

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Atmospheric boundary layer research at Halley,
Antarctica Phil S. Anderson Russ Ladkin John C.
King British Antarctic Survey Natural Environment
Research Council Cambridge, UK j.c.king_at_bas.ac.uk
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Why study the ABL in Antarctica ?

• Boundary-layer processes exert strong control
  over
• SH high latitude circulation, driving the
  katabatic
• circulation.
• Boundary-layer parametrisations currently used
  in
• GCMs may not be appropriate for Antarctic
  conditions
• Antarctica offers some near-ideal sites for SBL
  studies
• - little or no diurnal variation
• - strong stability
• - uniform, flat and unobstructed sites
• Turbulent transport is a key part of air-snow
  exchange

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Halley Research Station

• 75oS, 26oW, 30 m.a.s.l.
• Brunt Ice Shelf - flat, uniform, unobstructed
• Prevailing easterlies have gt 50 km fetch
• 3 months of winter darkness
• Synoptic and upper-air station (WMO 89022)

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History of boundary-layer studies at Halley (1)
1986 Stable Antarctic Boundary Layer Expt.
(STABLE) 10-min eddy-correlation fluxes from
sonic anemometers at 5, 15, 30m Profiles of
mean wind and temperature to 30m Sodar 1991
STABLE-II As STABLE, plus Microbarograph
array Blowing snow measurements
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History of boundary-layer studies at Halley (2)
1995 - 2000 FLUX/Polar Snow 10-min eddy
correlation fluxes at 4m Limited profile to 10
m Snow surface and snowpack temperatures Solar
and terrestrial radiation Sodar Tethersonde
profiling 1995 - ? Katabatic wind studies AWS
network up continental slope inland from
Halley Autonomous doppler sodar deployed 2002
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Autonomous Doppler Sodar system
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Planned measurements at Halley, 2002-2005

• Turbulence
• Metek sonic anemometers at 4, 15, 30m
• Sampling at 40Hz, recorded continuously at 10Hz
• 2 additional Meteks at 10m on remote masts
• Applied Technologies M100 infrared hygrometer
  for
• fast-response water vapour measurement

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Planned measurements at Halley, 2002-2005

• Mean profiles
• Vaisala HMP35 (Temperature/humidity) in
  aspirated
• radiation shields at 1, 2, 4, 8, 15 and 30m
• RM Young propellor/vane Wind Monitor at 1, 2, 4,
  8,
• 15 and 30m
• Cooled-mirror frost point hygrometer (Michell
• Dewmet) for accurate humidity measurement
• Record 10-minute means

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Planned measurements at Halley, 2002-2005

• Radiation and snow temperature
• Global, diffuse and reflected shortwave (Kipp
• Zonen solarimeters, aspirated and heated)
• Downwelling and upwelling longwave (Kipp Zonen
• pyrgeometers, aspirated and heated)
• Didcot Instruments net radiometer
• 2 x Heitronics infrared thermometers for snow
• surface temperature
• Snow temperature profile to 10m depth
• Record 10 minute means

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Planned measurements at Halley, 2002-2005

• Other measurements
• Microbarograph array
• Sodar array
• Kite / helikite tethersonde for measuring
  temperature,
• humidity and wind profiles to 500m. Usually
  used
• during limited, intensive campaigns
• Routine daily (1200 UTC) launch of Vaisala
• radiosonde with GPS windfinding. Sounding to
• 100 hPa. Fine structure data retained.
• (contact BAS Meteorological and Ozone
  Monitoring
• Unit for data)

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Further information

• Bibliography please take one
• Science queries to John King or Phil Anderson
• Technical queries on instruments to Russ Ladkin