Precise observations of the atmospheric temperature profile by fast-response high-resolution tungsten sondes

Kensaku Shimizu

Faculty of Environmental Earth Science, Hokkaido University

We recently developed a 6 Hz high-speed sampling temperature sensor that uses the temperature dependence of the electrical resistance of the fine tungsten wire that was once used for the rocketsondes. Its response time estimated from the result of laboratory experiments is only 46 ms at 10 hPa, and as a result, the solar radiation error is estimated to be 0.5 K or less in daytime.

During the early development stage, numerous pulses, positive in daytime and negative in nighttime, are found. The amplitude increases with height, and reaches 7 K at 10 hPa in daytime. At first, these pulses are interpreted as temperature disturbances generated by short-wave heating on balloon surface in daytime and adiabatic cooling of a balloon internal gas and long-wave cooling on balloon surface in nighttime. However detailed analyses of a pair of GPS positional data at the balloon neck and the hanging-down sonde reveal that they are due to thermal contamination arising primarily from sonde package box with some additional effect from the launching balloon. This influence from sonde package box has been eliminated by modifying the mount of the sensor. On the other hand, the balloon effect could be avoided by using the long suspension lines. Some remaining small fluctuations with the magnitude of less than 0.5 K are interpreted as those caused by the solid angle modulation of the illumination against the sensor body. They are removed by applying some filtering procedure to the observed data. As a result, the tungsten sonde has become a kind of a reference for a precise observation of the vertical temperature profile, and is now available as a commercial product named MTR.

This talk will present our experience of MTR temperature observations together with the preliminarily analyses on the fine scale temperature structures. We will also introduce 16-Hz special model MTR, aerosol sonde, CO2 sonde, and hydrometer video sonde.

Monday, 31 October 2011, 10:30 PM

Refreshments 10:15 AM

NCAR-Foothills Laboratory

3450 Mitchell Lane

Bldg 2 Auditorium (Rm1022)

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Start: 
Tuesday, October 25, 2011
End: 
Monday, October 31, 2011