Detecting supercooled liquid water droplets in clouds
The partitioning of water between the ice and liquid phases in a cloud is a poorly known quantity. If the cloud temperature is between about -35° and 0°, supercooled liquid may coexist with the ice. The supercooled liquid is what causes icing of aircraft, and is a major hazard. More fundamentally, the ice-fraction of such a cloud partly determines the radiative transport properties of clouds; in other words whether there is a net upwelling or downwelling of radiant energy. This is of great importance to weather and climate models.
We are developing a sensor (a "polarsonde") for supercooled liquid in clouds that will be an enhancement for radiosondes. It is based on the detection of differences in the scattering of light from an LED by the water droplets or ice crystals. Currently (2012/13) we are testing prototypes at a station on the Greenland ice sheet where there is a suite of cloud measurement instruments suitable for validating ours.
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A polarsonde attached to a |
Reinstallation of polarsonde on Summit Camp Met. tower |
Student Projects available. Contact A/Prof Murray Hamilton
Personnel
A/Prof Murray Hamilton
Huichao (Nicky) Luo
Funding: This project receives support from the Sir Ross and Sir Keith Smith Fund.
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