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Heat flow , q (mW/m 2 ). q = - k dT / dz k = thermal conductivity dT / dz = thermal gradient. Sediment below ice. each sensor. Partial equilibration. Temperature sensors. Temperature. Penetration. Probe extraction. Bottom water. Time. WISSARD heat flow probe. Master
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Heat flow, q (mW/m2) q = -kdT/dz k = thermal conductivity dT/dz = thermal gradient Sediment below ice each sensor... Partial equilibration Temperature sensors Temperature Penetration Probe extraction Bottom water Time
WISSARDheat flow probe Master machinist Key features: • Stainless steel construction (except for two brass rings) • Max. diameter = 25 cm • Length, ~2.5–3 m (2 or 3 sensors on lance) • Adjustable weight, ~200-450 kg • Autonomous outrigger probes • Bottom water and tilt sensors • Shipping crate with integrated cradle for servicing, launch, recovery Weight stand Lance
Weight stand features Tapered upset 6 U-channels (hold weights) Front Tapered upset Weight clamp Rear Limited travel on pin Stabilizing ring (holds lance) Oceanographic-grade swivel 7 klb strength No grease Outrigger mount
Autonomous outrigger probes Clamshell protects logger Delrin outrigger Thermistor in long probe Pressure case Bolted on lance Short tip version (for bottom water) Electronics and battery 16-bit A/D 1 mK resolution Calibrated (NIST-traceable) to ± 2 mK Deck box (program, download) Through-case serial communication
Thermal conductivity system, data processing Thermal conductivity • Needle probe method • Constant heating • Custom software for acquisition and processing Heat flow processing • Extrapolation of 6-7 minutes of subsurface data • Multiple probes --> gradient • Combine with thermal conductivity --> heat flow • Monte Carlo analysis of uncertainties