Studies of Turbulent Transport Processes in the Atmospheric Boundary Layr by Wavelet Analysis.

• Project/Area Number: 04640417
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 気象・海洋・陸水学
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: MITSUTA Yasushi Kyoto University, Disaster Prevention Research Institute, Professor, 防災研究所, 教授 (90027219)
• Co-Investigator(Kenkyū-buntansha): HORIGUCHI Mistuaki Kyoto University, Disaster Prevention Research Institute, Research Associate, 防災研究所, 助手 (60190253) ; HAYASHI Taiichi Kyoto University, Distaste Prevention Research Institute, Research Associate, 防災研究所, 助手 (10111981) ; YAMADA Michio University of Tokyo, Graduate School of Mathematicalsciences, Assistant Professo, 大学院・数理科学研究所, 助教授 (90166736)
• Project Period (FY): 1992 – 1994
• Project Status: Completed (Fiscal Year 1994)
• Budget Amount: ¥2,100,000 (Direct Cost: ¥2,100,000); Fiscal Year 1994: ¥300,000 (Direct Cost: ¥300,000); Fiscal Year 1993: ¥300,000 (Direct Cost: ¥300,000); Fiscal Year 1992: ¥1,500,000 (Direct Cost: ¥1,500,000)
• Keywords: Wavelet / Desert Wavelet Transform / Analysis of Abrupt Phenomenon / Gust Front / Momentum Transport / 山岳波の特性 / 離散ウェイブレット変換 / スペクトル解析

Research Abstract

The purpose of the present study is to establish the practical method of wavelet analysis applicable for the study of abrupt phenomenon in the atmospheric boundary layr. The traditional method of power spectrum analysis can be used for the analysis of stationary time series, but it is not applicable to abrupt changes. While wavelet analysis can determine the time and magnitude of abrupt fluctuation.
In the course of wind velocity changes in the storm, it increases suddenly accompanied by descending of high speed air mass from free atmosphere. In such case wavelet analysis is especially effective.
Yamada has developed the algorithm for the discrete orthogonal wavelet transform using the FFT.Hayashi used this algorithm for the study of wind velocity fluctuation and momentum transport in the atmospheric surface layr, and found that large downward transports occur intermittently in the energy containing frequency range accompanied by sweep or ejection.

Research Products

• [Publications] Hayashi,T: "An analysis of Wind Velocity Eluctuation in the Atomspheric Surface Layer Using the Orthonormal Wavelet Transform." Boundary-Layer Meteorology. 70. 307-326 (1994)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] 光田寧: "花巻空港付近の気流の特性について" 京都大学防災研究所年報. 38(発表予定). (1995)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] M.Yamada: "Application of Wavelet Analysis for the Study of atmospheric Turbulence (in Japanese)" Tenki. Vol.40, No.9. 663-670 (1993)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] T.Hayashi: "An analysis of Wind Fluctuations in the Atmospheric surface Lager Using on Orthonormal Wavelet Transform." Boundary Layr Meteorology. Vol 70. 307-326 (1994)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Hayashi,T: "An analysis of Wind Velocity Eluctuation in the Atomspheric Surface Layer Using the Orthonormai Wavelet Transtorm." Boundary-Layer Meteorology. 70. 307-326 (1994)
• [Publications] 光田 寧: "花巻空港付近の気流の特性について" 京都大学防災研究所年報. 38(発表予定). (1995)
• [Publications] 山田道夫: "大気乱流へのウェイブレット解析の応用" 天気. 40. 663-670 (1993)
• [Publications] Hayashi,T.: "An Analysis of Wind Velocity Fluctuation in the Atmospheric Layer by the Orthonormal Wavelet Transform." Boundary-Layer Meteorology. 68(印刷中). (1994)