Instantaneous phase shift of annual subsurface temperature cycles derived by the Hilbert-Huang transform

NCUIR > College of Earth Sciences > DEPARTMENT OF SPACE SCIENCE AND ENGINEERING > journal & Dissertation > Item 987654321/102216

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/102216

Title:	Instantaneous phase shift of annual subsurface temperature cycles derived by the Hilbert-Huang transform
Authors:	劉正彥;Sun, Yang-Yi;Chen, Chieh-Hung;Liu, Jann-Yenq;Wang, Chung-Ho;Chen, Deng-Lung
Contributors:	地球科學學院太空科學與工程學系
Keywords:	Geophysics;Harmonics;Heat transport;Hilbert-Huang transform;Meteorology;Oscillations;Pacific Decadal Oscillation;Phase shift;Precipitation;Rainfall intensity;Reduction;Seasonal variations;subsurface temperature;Surface temperature;Temperature;Thermal diffusivity;Transforms;Transport
Date:	2015-01-01
Issue Date:	2026-04-23 11:04:19 (UTC+8)
Publisher:	Wiley-Blackwell;Washington: Blackwell Publishing Ltd
Abstract:	摘要： AbstractThis study uses the Hilbert‐Huang transform to compute the instantaneous (daily) phase shift between temperature signals at the ground surface and at a depth of 5 m. This approach is not restricted to the stationary harmonic surface temperature assumptions invoked by analytical solutions. The annual cycles are extracted from the ground surface temperatures and the shallow subsurface temperatures at 5 m depth recorded at the Hualien (23.98°N, 121.61°E) and Ilan (24.77°N, 121.75°E) meteorology stations of Central Weather Bureau in Taiwan from 1952 to 2008. Significant reductions in the phase shift and increases in the estimated thermal diffusivity from 1980s to 1990s are found and suggest that the recent warming of the Pacific Decadal Oscillation may affect heat transport in the subsurface environment. The marginal spectra of the instantaneous phase shifts and the precipitation intensity records at Hualien and Ilan reveal that precipitation may play a role in the evolution of seasonal variation in shallow subsurface heat transport. 其他題名： J. Geophys. Res. Atmos 出版者： Washington: Blackwell Publishing Ltd 出版日期： 2015-03-16 出處： Journal of Geophysical Research: Atmospheres, 2015-03, Vol.120 (5), p.1670-1677 資源來源： Wiley Online Library 版權： 2015. American Geophysical Union. All Rights Reserved. 識別號： ISSN: 2169-897X 識別號： EISSN: 2169-8996 識別號： DOI: 10.1002/2014JD022574
Appears in Collections:	[DEPARTMENT OF SPACE SCIENCE AND ENGINEERING] journal & Dissertation

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