Lead Fluxes

Andreas Held, Caroline Leck, Ian Brooks, Barbara Brooks,

Sarah Norris

SOURCES

TRANSPORT DRY DEPOSITION

open sea sea-ice lead

TRANSFORMATION

surface albedo

cloud albedo

CCNscattering & absorption

WET DEPOSITION

Simplified Arctic Aerosol Life Cycle

Open Lead Flux System

1) Gill sonic anemometer

2) CLASP optical particle counter

(0.24 < Dp < 18.5 µm)

3) CPC 3760A condensation particle

counter (Dp > 11 nm)

4) LICOR 7500 CO2/H2O analyzer

5) MOXA dataloggerCLASP units

LiCOR 7500

sonicanemometer

Examine the capacity of the open leads to emit particles to the air by eddy covariance measurements:

fully battery operated (low power consumption)

located close to the ice edge ~2 m above the surface, near bubble camera site

Neutral Case

z/L=0z0=0.001 m, σv / u* = 2zm=1, 2, 3 m

wind

10 20 50 100 mPhoto: H.J. Zwally, NASA Goddard

Footprint Analysis of Open Lead Flux System

FSAM (Schmid, 1994)

Pu

mp

Sensing head

25 cm

• 16 channels - 0.24 to 18.5 m diameter• Flow rate 3 l/min – high sampling statistics allows 10 Hz temporal

resolution• Compact (25 x 8 x 6 cm) – allows collocation with sonic anemometer,

short inlet tube and low flow distortion, & installation in balloon instrument package and on buoy

CLASP Instrument

• Total particle number concentration for Dp > 11 nm

• Flow rate 1.5 l/min – good counting statistics

• 10 Hz sampling, but actual time response is slower

• Provides additional size bin from 10 nm to 240 nm in combination w/ CLASP

Condensation Particle Counter

Spray Sampler for Filter Collection and Electron Microscopy

Stockholm prototype:

• artificial bubble generation below water surface

• adjustable bubble diameter to generate film/jet droplets

• spray collection w/ filter sampler for off-line analysis

• spray collection on EM grid for electron microscopy

• free floating on water

• height adjustment of bubbler & sampler