Sediment below ice Temperaturesensors q = -k dT/dz k = thermal conductivity dT/dz = thermal gradient Temperature Time each sensor... Heat flow, q (mW/m 2 ) Bottomwater Penetration Partialequilibration Probeextraction

WISSARD heat flow probe Weight stand Lance Mastermachinist Key features: Stainless steel construction (except for two brass rings) Stainless steel construction (except for two brass rings) Max. diameter = 25 cm Max. diameter = 25 cm Length, ~2.5–3 m Length, ~2.5–3 m (2 or 3 sensors on lance) (2 or 3 sensors on lance) Adjustable weight, ~ kg Adjustable weight, ~ kg Autonomous outrigger probes Autonomous outrigger probes Bottom water and tilt sensors Bottom water and tilt sensors Shipping crate with integrated cradle for servicing, launch, recovery Shipping crate with integrated cradle for servicing, launch, recovery

Weight stand features Stabilizing ring (holds lance) Taperedupset 6 U-channels (hold weights) Front Rear Taperedupset Weightclamp Oceanographic-grade swivel Limited travel on pin 7 klb strength No grease Outrigger mount

Autonomous outrigger probes Deck box (program, download) Clamshell protects logger Bolted on lance Electronics and battery Pressure case Short tip version (for bottom water) 16-bit A/D 1 mK resolution Calibrated (NIST-traceable) to ± 2 mK Through-case serial communication Thermistor in long probe Delrin outrigger

Thermal conductivity system, data processing Thermal conductivity Needle probe method Needle probe method Constant heating Constant heating Custom software for acquisition and processing Custom software for acquisition and processing Heat flow processing Extrapolation of 6-7 minutes of subsurface data Extrapolation of 6-7 minutes of subsurface data Multiple probes --> gradient Multiple probes --> gradient Combine with thermal conductivity --> heat flow Combine with thermal conductivity --> heat flow Monte Carlo analysis of uncertainties Monte Carlo analysis of uncertainties