Coherent modes in multi‐scale variability of precipitation over the headwater catchments in the Pearl River basin,South China |
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| Authors: | Jun Niu Ji Chen Keyi Wang Bellie Sivakumar |
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| Institution: | 1. Center for Agricultural Water Research in China, China Agricultural University, Beijing, China;2. College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China;3. Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong;4. School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, Australia;5. Department of Land, Air and Water Resources, University of California, Davis, CA, USA |
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| Abstract: | This paper studies the coherent modes of multi‐scale variability of precipitation over the headwater catchments in the Pearl River basin in South China. Long‐term (1952–2000) daily precipitation data spatially averaged for 16 catchments in the basin are studied. Wavelet transform analysis is performed to capture the fluctuation embedded in the time series at different temporal timescales ranging from 6 days to 8.4 years. The catchment clusters of the coherent modes are delineated using the principal component analysis on the wavelet spectra of precipitation. The results suggest that as much as 98% of the precipitation variability is explained by only two coherent modes: high small‐scale mode and high seasonal mode. The results also indicate that a large majority of the catchments (i.e., 15 out of 16) exhibit consistent mode feature on multi‐scale variability throughout three sub‐periods studied (1952–1968, 1969–1984, and 1985–2000). The underlying effects of the coherent modes on the regional flood and drought tendency are also discussed. |
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| Keywords: | coherent mode Pearl River precipitation variability principal component analysis wavelet transform |
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