1988 Fiscal Year Final Research Report Summary
Estimation of liquid water content and water vapor amount in the polar region
| Project/Area Number |
61540304
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
KAWAGUCHI Sadao National Institute of Polar Research, Chief Research Officer, Professor, 教授 (40000153)
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| Co-Investigator(Kenkyū-buntansha) |
KANZAWA Hiroshi National Institute of Polar Research, Division of data collection and processing, 資料系, 助手 (20150047)
AOKI Shuji National Institute of Polar Research, Division of Research, Research Associate., 研究系, 助手 (00183129)
WADA Makoto National Institute of Polar Research, Division of Research, Research Associate., 研究系, 助手 (40132716)
FUJII Yoshiyuki National Institute of Polar Research, Division of Research, Associate Professor., 研究系, 助教授 (20125214)
YAMANOUCHI Takashi National Institute of Polar Research, Division of Research, Associate Professor., 研究系, 助教授 (00141995)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Antarctic Climate Research / Liquid water content / Water vapor amount / Microwave radiometer / Satellite / AVHRR imagery / Discrimination of clouds / TOVS. |
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| Research Abstract |
Clouds and water vapor work as an important factors of the climate in the Antarctic. This study aimes to obtain the method to derive liquid water content of clouds and water vapor amounts from groundbased microwave observations and satellite data.
1. As for the microwave observation, radiometers of three frequency range, 12, 19 and 37 GHz were examined. From the preliminary observation in Japan, combination of rediometers of three frequency regions works effective to get the cloud information. However, in the polar region, because of small amount of liquid water and water vapor, 12 GHz radiometer was not suitable and 19 GHz radiometer, which was expected to be effective for water vapor measurements, did not offer a meaning value of water vapor. It was shown that the single frequency measurements by the 37 GHz radiometer was enough to derive liquid water content under the polar atmosphere where the amount of water vapor and liquid water are small, if the physical temperature of antenna was monitored.
2. The method to discriminate clouds by AVHRR data of NOAA satellite was examined. Since the cloud cover over the snow surface in the polar region is difficult to detect only by the visible reflection or infrared brightness temperature, the differences of infrared brightness temperatures were used. The differences between the brightness temperature in 4 mum region (ch 3) and 10 mum region (ch 4), 10 mum and 12 mum region (ch 5) were used together with the 2 dimentional histogram of the brightness temperature and the difference.
3. Atmospheric water vapor amount was derived from the TIROS Operational Veritcal Sounder (TOVS) of NOAA satellite. Since the strong surface inversion affects the analysis, iteration method with considering the surface temperature explicitly was used. Comparing to the aerological data, though the vertical profile shows large disagreements, the column amounts of water vapor agreed within small variations.
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