Development of a cloud particle sensor for radiosonde sounding
| Autor: | Taro Nakagawa, Takashi Shibata, Masatomo Fujiwara, Kensaku Shimizu, Hideaki Kawagita, Atsushi Shimizu, Kazuo Sagara, Noma Yasuhisa, Toru Arai, Takuji Sugidachi, Satoshi Okumura, Yoichi Inai, Suginori Iwasaki, Mayumi Hayashi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Atmospheric Science
Daytime 010504 meteorology & atmospheric sciences Particle number Meteorology lcsh:TA715-787 lcsh:Earthwork. Foundations 01 natural sciences Light scattering lcsh:Environmental engineering law.invention 010309 optics Troposphere Depth sounding law Liquid water content 0103 physical sciences Radiosonde Environmental science Cirrus lcsh:TA170-171 0105 earth and related environmental sciences Remote sensing |
| Zdroj: | Atmospheric Measurement Techniques, Vol 9, Iss 12, Pp 5911-5931 (2016) |
| ISSN: | 1867-8548 |
| Popis: | A meteorological balloon-borne cloud sensor called the cloud particle sensor (CPS) has been developed. The CPS is equipped with a diode laser at ∼ 790 nm and two photodetectors, with a polarization plate in front of one of the detectors, to count the number of particles per second and to obtain the cloud-phase information (i.e. liquid, ice, or mixed). The lower detection limit for particle size was evaluated in laboratory experiments as ∼ 2 µm diameter for water droplets. For the current model the output voltage often saturates for water droplets with diameter equal to or greater than ∼ 80 µm. The upper limit of the directly measured particle number concentration is ∼ 2 cm−3 (2 × 103 L−1), which is determined by the volume of the detection area of the instrument. In a cloud layer with a number concentration higher than this value, particle signal overlap and multiple scattering of light occur within the detection area, resulting in a counting loss, though a partial correction may be possible using the particle signal width data. The CPS is currently interfaced with either a Meisei RS-06G radiosonde or a Meisei RS-11G radiosonde that measures vertical profiles of temperature, relative humidity, height, pressure, and horizontal winds. Twenty-five test flights have been made between 2012 and 2015 at midlatitude and tropical sites. In this paper, results from four flights are discussed in detail. A simultaneous flight of two CPSs with different instrumental configurations confirmed the robustness of the technique. At a midlatitude site, a profile containing, from low to high altitude, water clouds, mixed-phase clouds, and ice clouds was successfully obtained. In the tropics, vertically thick cloud layers in the middle to upper troposphere and vertically thin cirrus layers in the upper troposphere were successfully detected in two separate flights. The data quality is much better at night, dusk, and dawn than during the daytime because strong sunlight affects the measurements of scattered light. |
| Databáze: | OpenAIRE |
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