日本地球惑星科学連合2014年大会

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ポスター発表

セッション記号 A (大気海洋・環境科学) » A-AS 大気科学・気象学・大気環境

[A-AS22_1PO1] 大気化学

2014年5月1日(木) 18:15 〜 19:30 3階ポスター会場 (3F)

コンビーナ:*竹川 暢之(東京大学先端科学技術研究センター)、澤 庸介(気象研究所地球化学研究部)、金谷 有剛(独立行政法人海洋研究開発機構地球環境変動領域)、高橋 けんし(京都大学生存圏研究所)、谷本 浩志(国立環境研究所)

18:15 〜 19:30

[AAS22-P01] ヨウ化物イオンを含む凍結した水溶液からのヨウ素分子と一酸化ヨウ素の放出

奥村 将徳1、*薮下 彰啓1 (1.京都大学)

キーワード:ヨウ素, 一酸化ヨウ素, 氷, オゾン, 不均一反応, キャビティーリングダウン分光法

This study aims to develop a new method to observe water vapor horizontal distribution using a side-lobe emission of the 1.3 GHz-band wind profiling radar (WPR). The phase delay of the received side-lobe emission is mainly due to the refractive index fluctuation along the propagation path. In the atmospheric boundary layer, the temporal and spatial non-uniformity of water vapor determines the refractive index fluctuation. Main scope of the study is to extract humidity information from the atmospheric phase delay of side-lobe emission from a WPR. Horizontal humidity distribution can be derived by the data assimilation into numerical prediction model.
The receiver system and data analysis algorithm were developed. A software radio, USRP N200 with an RX daughter board was employed to detect side-lobe emission received by an antenna. A Rubidium frequency standard and a 1 pps signal source of GPS receiver were used for accurate estimation of phase delay variation. The frequency stability of a crystal oscillator, which is generally employed for a reference frequency source of WPR, is insufficient for the accurate estimation. We proposed a new method to compensate the frequency uncertainty of WPR by using data of the additional receiver nearby the WPR site.
IQ data detected by USRP B210 which is controled by GNURadio, an open source software. By using GNURadio the system will be low cost.The program written in IDL language extracts the temporal variation of the phase delay from the received IQ signal. In order to achieve good performance even in low SNR conditions, we developed an algorithm using STFT (Short-term Fourier transformation) aiming to remove noise in undesired frequency range.
The developed system is promising to derive humidity information from side-lobe emission from various WPRs such as the operational WPR network in Japan (WINDAS (WInd profiler Network and Data Acquisition System)).