Rainfall–runoff relations for karstic springs. Part II: continuous wavelet and discrete orthogonal multiresolution analyses

Labat, David; Ababou, Rachid; Mangin, A.

doi:10.1016/s0022-1694(00)00322-x

Cited by 361 publications

(209 citation statements)

References 29 publications

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“…It has been used for numerous studies in geosciences (e.g., [13,58,59]). In particular, applications of wavelets to discharge time series allow describing signals of climatic oscillation [14,16,60,61].…”

Section: Methodsmentioning

confidence: 99%

Characterization of the Interannual Variability of Precipitation and Streamflow in Tensift and Ksob Basins (Morocco) and Links with the NAO

et al. 2016

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Abstract:The aim of this study is to understand the inter-annual hydrological variability (precipitation and streamflow) in the basins of the High Atlas in Morocco and to determine how climate fluctuations (represented by the North Atlantic Oscillation (NAO) climate index) are expressed in the hydrological system. To reach this objective, time series of precipitation and streamflow are processed as standardized anomalies and studied by continuous wavelet analysis and wavelet coherence analysis, which are particularly suitable for the study of unsteady processes. Wet and dry periods vary from one basin to another between three and five years. The wavelet analysis shows the existence of many bands of energy in most of the sub-basins, from annual to inter-annual scales regarding the precipitation and streamflow time series. These bands correspond to intervals of one year, 2-4 years, 4-8 years and 8-12 years. The wavelet coherence analysis shows a strong coherence between NAO/streamflow and precipitation/NAO identified at the inter-annual scale. Non-stationarity can be observed in the late 1980s, 1990s and 2000s. The contribution of the NAO is different from one basin to another ranging between 67% and 77%.

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Section: Methodsmentioning

confidence: 99%

Characterization of the Interannual Variability of Precipitation and Streamflow in Tensift and Ksob Basins (Morocco) and Links with the NAO

et al. 2016

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“…The key and difficulty of the wavelet analysis is to select appropriate wavelet bases [28]. This paper selects the Morlet complex wavelet [29] that can faithfully reflect the time sequence various cycles and time domain distribution as the wavelet base. The real part and module of the Morlet complex wavelet exchange are two important variables in the wavelet analysis.…”

Section: The Wavelet Analysis Methodsmentioning

confidence: 99%

Annual Precipitation Fluctuation and Spatial Differentiation Characteristics of the Horqin Region

et al. 2017

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Abstract:Precipitation is the main water source for vegetation survival in arid and semi-arid areas. However, previous studies always focus on the effects of precipitation in different time scales, but ignore the effects of precipitation in different spatial scales. To further study the effects of precipitation fluctuation in different spatial scales, we used the wavelet analysis method to analyze its temporal and spatial change based on data from eighteen meteorological stations during 1961-2015 in Horqin region. Results showed that: (1) from the overall tendency of precipitation changes, the precipitation inter-annual variations in Horqin region had the tendency of gradually decreasing from the southeast (District IV) to the northwest; (2) the precipitation anomalies of District I-IV between 1960 and 1980 were small and approximate to the normal value; (3) in the time scale of 23-32 years, the cyclical fluctuations were very significant and the annual precipitation underwent two cyclical fluctuations from a period of low precipitation to a period of high precipitation; and (4) as results of analyzing the spatial wavelet variance of sub-region, the main cycle of precipitation in District I, District II and District III was between 10 and 11 years, while the main cycle of precipitation in District IV was 25 years. The main conclusions include the following. (1) This region tended to be arid, and the precipitation gradually decreased from the southeast (District IV) to northwest (District I). (2) The influence of spatial differentiation characteristics on precipitation fluctuation in this region was cyclical fluctuation, which gradually decreased from the southeast to the northwest. The length of the cyclical change period gradually shortened. In the first main cycle, whose annual precipitation changes were most significant, the changing characteristic was District IV and District I decreased from 25 years to 10 years. (3) Predicated from the cyclical changing law that the annual precipitation decreases from high to low, the Horqin region will remain in a period of low precipitation between 2016 and 2020.

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“…The CWT is a mathematical tool which allows the decomposition of the signal f (t) in terms of elementary contributions called wavelets, which can be thought of as a packet of sine waves of varying amplitude and wavelength (Sadowskey, 1996;Torrence and Compo, 1998;Labat et al, 2000). For time series f (t) ∈ L 2 (R), R is the domain of real numbers, or finite energy signal, the CWT of signal f (t) with the analyzing wavelet φ is the convolution of f (t) with a set of dilated and translated wavelets:…”

Section: Continuous Wavelet Transform (Cwt) and Wavelet Power Spectrumentioning

confidence: 99%

“…Since the hydrometeorological signals are highly nonstationary and their physical processes often operate under a large range of scales varying from 1 day to several decades, the continuous wavelet transform (CWT) has been introduced and developed to reveal the multiple time scales characteristics of these nonstationary signals (Mandelbrot and Wallis, 1968;Grossmann and Morlet, 1984;Mallat, 1989;Daubechies, 1994;Torrence and Compo, 1998;Labat et al, 2000). Because the CWT can provide information about both time and frequency simultaneously, and enables a separation to be made between features associated with different characteristic length scales, it has some advantages over the traditional Fourier transform and has been widely used in revealing the periodic characteristics of hydrometeorological signals at multiple time scales (Walker, 1997;Nener et al, 1999;Coulibaly and Bum, 2004;Labat et al, 2005;Shark and Yu, 2006;Liu et al, 2009;Yu et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Improvement for the multi-scale periodic characteristics revealing of precipitation signals and its impact assessment on soil hydrological process by combining HHT and CWT approaches

Yang

Liu

Yao

et al. 2015

Nat. Hazards Earth Syst. Sci.

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Abstract. This study conducts a detailed analysis of multiscale periodic features involved in the annual and seasonal precipitation signals at the typical coastal reclamation region in China by selecting the suitable continuous wavelet transform (CWT) and innovatively combining the improved Hilbert-Huang transform (HHT), and further deduces the precipitation trend and its impacts on the future soil hydrological process. The Morlet wavelet transform is proved suitable in revealing the precipitation signals broad-scale periodicities, however, the critical mode mixing problem in CWT causes the poor significance in the fine-scale periodicities, which cannot well match the climate background. By combining the HHT approach, the fine-scale mode mixing drawback in CWT is effectively eliminated, and the the studied precipitation signals multi-scale periodicities are accurately revealed. Consequently, an overall decreasing trend of annual and seasonal precipitation in future years is demonstrated. Furthermore, by novelly using the cross wavelet transform (XWT) and wavelet transform coherence (WTC) approaches, the prominent correlations between the precipitation dynamics and soil and groundwater salinities dynamics, it is demonstrated that the precipitation increase can effectively leach the surface soil salt downwards into the deeper soil layers and groundwater with 5-7-day lag in the new cultivated tidal land. The revealed future decreasing trend of precipitation, especially in spring and summer, may aggravate the soil salinization at the coastal reclamation region, thus some reasonable salt leaching and evaporation suppression measures need to be taken to prevent the possible soil secondary salinization process.

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Rainfall–runoff relations for karstic springs. Part II: continuous wavelet and discrete orthogonal multiresolution analyses

Cited by 361 publications

References 29 publications

Characterization of the Interannual Variability of Precipitation and Streamflow in Tensift and Ksob Basins (Morocco) and Links with the NAO

Characterization of the Interannual Variability of Precipitation and Streamflow in Tensift and Ksob Basins (Morocco) and Links with the NAO

Annual Precipitation Fluctuation and Spatial Differentiation Characteristics of the Horqin Region

Improvement for the multi-scale periodic characteristics revealing of precipitation signals and its impact assessment on soil hydrological process by combining HHT and CWT approaches

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