Extraction of Nonlinear Rainfall Trends Using Singular Spectrum Analysis

Unnikrishnan, Poornima; Jothiprakash, V.

doi:10.1061/(asce)he.1943-5584.0001237

Cited by 31 publications

(8 citation statements)

References 41 publications

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“…The embedding approach constructs a sequence of {X discharge (t)} of M -dimensional vectors from the original time series by using lagged copies of the scalar data {X discharge (t) : 1 ≤ t ≤ N } (see, Ghil et al, 2002), (see more details in Ghil et al, 2002). From the SVD decomposition, meaningful time series are reconstructed by means of diagonal averaging (see, e.g., Unnikrishnan and Jothiprakash, 2015;Ghil et al, 2002). The method offers useful insights into understanding non-linear systems and is here employed to explore the relationship of river discharge oscillations of the Congo basin with GRACE-derived TWS.…”

Section: Singular Spectral Analysismentioning

confidence: 99%

Changes in hydro-meteorological conditions over tropical West Africa (1980–2015) and links to global climate

Ndehedehe

Awange

Agutu

et al. 2018

Global and Planetary Change

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The role of global sea surface temperature (SST) anomalies in modulating rainfall in the African region has been widely studied and is now less debated. However, their impacts and links to terrestrial water storage (TWS) in general, have not been studied. This study presents the pioneer results of canonical correlation analysis (CCA) of TWS derived from both global reanalysis data (1980−2015) and GRACE (Gravity Recovery and Climate Experiment) (2002 − 2014) with SST fields. The main issues discussed include, (i) oceanic hot spots that impact on TWS over tropical West Africa (TWA) based on CCA, (ii) long term changes in model and global reanalysis data (soil moisture, TWS, and groundwater) and the influence of climate variability on these hydrological indicators, and (iii) the hydrological characteristics of the Equatorial region of Africa (i.e., the Congo basin) based on GRACE-derived TWS, river discharge, and precipitation. Results of the CCA diagnostics show that El-Niño Southern Oscillation related equatorial Pacific SST fluctuations is a major index of climate variability identified in the main portion of the CCA procedure that indicates a significant association with long term TWS reanalysis data over TWA (r = 0.50, ρ < 0.05). Based on Man-Kendall's statistics, the study found fairly large long term declines (ρ < 0.05) in TWS and soil moisture (1982 − 2015), mostly over the Congo basin, which coincided with warming of the land surface and the surrounding oceans. Meanwhile, some parts of the Sahel show significant wetting (rainfall, soil moisture, groundwater, and TWS) trends during the same period (1982 − 2015) and aligns with the ongoing narratives of rainfall recovery in the region. Results of singular spectral analysis and regression confirm that multi-annual changes in the Congo river discharge explained a considerable proportion of variability in GRACEhydrological signal over the Congo basin (r = 0.86 and R 2 = 0.70, ρ < 0.05). Finally, leading orthogonal modes of MERRA and GRACE-TWS over TWA show significant association with global SST anomalies.

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Section: Singular Spectral Analysismentioning

confidence: 99%

Changes in hydro-meteorological conditions over tropical West Africa (1980–2015) and links to global climate

Ndehedehe

Awange

Agutu

et al. 2018

Global and Planetary Change

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“…The singular spectrum analysis (SSA, see, Ghil et al, 2002) Ghil et al, 2002;Ndehedehe et al, 2018), et al, 2002). From the SVD method, meaningful time series are reconstructed by means of diagonal averaging (see, e.g., Unnikrishnan and Jothiprakash, 2015;Ghil et al, 2002). The reconstructed discharge time series (i.e., matrix of reconstructed principal components) obtained from the SSA scheme were compared with the leading temporal patterns of PCA-derived rainfall (Section 2.8.1) over the Flinders catchment using correlation analysis (only for the common period).…”

Section: River Discharge Oscillations Using the Singular Spectral Anamentioning

confidence: 99%

Predicting hot spots of aquatic plant biomass in a large floodplain river catchment in the Australian wet-dry tropics

Ndehedehe

Stewart‐Koster

Burford

et al. 2020

Ecological Indicators

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“…Rainfall is one of the most essential meteorological and hydrological elements, which has always been a common concern in various disciplines, mainly meteorology, hydrology, geology and ecology (Hu et al, 2019). Accurate information of rainfall at different timescales is of considerable significance for the advancement in meteorological and hydrological monitoring and forecasting in order to enhance the capability to cope with natural disasters and upgrade water resource management (Jones et al, 2013;Nayak et al, 2013;Unnikrishnan and Jothiprakash, 2015;Pham et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Characterization of daily rainfall variability in Hong Kong: A nonlinear dynamic perspective

Shu

Chan

et al. 2020

Intl Journal of Climatology

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Modelling and forecasting of rainfall behaviour are of essential importance in various hydrological and meteorological studies, which depends largely on properly understanding the underlying rainfall dynamics. In this paper, 20-years (i.e., 2000-2019) measurements of daily rainfall data at 6 rain gauge stations in Hong Kong were analysed in the framework of nonlinear dynamic analysis. Phase space reconstruction (PSR), recurrence plot (RP) and recurrence quantification analysis (RQA) were carried out to identify and characterize the chaotic nature of rainfall dynamics. The results of this study underscore the complex processes and variability that is associated with Hong Kong's rainfall data. The existence of chaos in rainfall process was well recognized across various stations. The rainfall dynamics were further investigated with respect to its inter-annual and monthly variability. The dependence of rainfall dynamics on different temporal scales was likewise examined, which indicates that the rainfall dynamics at finer resolution are less complex than those at coarser resolution, thus the consequent rainfall variability is less pronounced.

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Extraction of Nonlinear Rainfall Trends Using Singular Spectrum Analysis

Cited by 31 publications

References 41 publications

Changes in hydro-meteorological conditions over tropical West Africa (1980–2015) and links to global climate

Changes in hydro-meteorological conditions over tropical West Africa (1980–2015) and links to global climate

Predicting hot spots of aquatic plant biomass in a large floodplain river catchment in the Australian wet-dry tropics

Characterization of daily rainfall variability in Hong Kong: A nonlinear dynamic perspective

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