Possible Linkages of Hydrological Variables to Ocean–Atmosphere Signals and Sunspot Activity in the Upstream Yangtze River Basin

Abstract

Profiling the hydrological response of watershed precipitation and streamflow to large-scale circulation patterns and astronomical factors provides novel information into the scientific management and prediction of regional water resources. Possible contacts of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), sunspot activity to precipitation and streamflow in the upper Yangtze River basin (UYRB) were investigated in this work. Monthly precipitation and streamflow were utilized as well as contemporaneous same-scale teleconnections time series spanning a total of 70 years from 1951 to 2020 in precipitation and 121 years from 1900 to 2020 in streamflow. The principal component analysis (PCA) method was applied so as to characterize the dominant variability patterns over UYRB precipitation time series, with the temporal variability of first two modes explaining more than 80% of total variance. Long-term evolutionary pattern and periodic variation characteristics of precipitation and streamflow are explored by applying continuous wavelet transform (CWT), cross-wavelet transform (XWT) and wavelet coherence (WTC), analyzing multi-scale correlation between hydrological variables and teleconnections in the time-frequency domain. The results manifest that ENSO exhibits multiple interannual period resonance with precipitation and streamflow, while correlations are unstable in time and phase. PDO and sunspot effects on precipitation and streamflow at interannual scales vary with time-frequency domains, yet significant differences are exhibited in their effects at interdecadal scales. PDO exhibits a steady negative correlation with streamflow on interdecadal scales of approximately 10 years, while the effect of sunspot on streamflow exhibits extremely steady positive correlation on longer interdecadal scales of approximately 36 years. Analysis reveals that both PDO and sunspot have significantly stronger effects on streamflow variability than precipitation, which might be associated with the high spatiotemporal variability of precipitation.

Transformative Trends in Runoff and Sediment Dynamics and Their Influential Drivers in the Wuding River Basin of the Yellow River: A Comprehensive Analysis from 1960 to 2020

“…Wavelet analysis, a powerful statistical tool, was originally utilized in the field of signal processing and analysis and is currently widely applied in various disciplines, including hydrology and ecosystems [37][38][39]. Wavelet transformation can be categorized into continuous wavelet transform (CWT) and discrete wavelet transform (DWT).…”

Analysis of Influencing Factors of SST in Tropical West Indian Ocean Based on COBE Satellite Data

“…Cross wavelet transform is mainly used to analyze the relationship between the two parameters in the time-frequency domain. It is a new method that combines cross-spectrum analysis and wavelet analysis [28,29]. The expression is Equation ( 4)…”

Variability of River Runoff in Poland and Its Connection to Solar Variability

“…Dai et al [1] proved that the solar and lunar periodic motions (SLPMs) had substantial impacts on the runoff of the world's large rivers. Yang and Xing [37] searched for possible linkages of hydrological variables to ocean-atmosphere signals and sunspot Activity in the upstream Yangtze River basin and found that both the Pacific Decadal Oscillation and the sunspot had significantly stronger effects on streamflow variability than precipitation, which might be associated with the high spatiotemporal variability of precipitation. Mares et al [38] investigated the possible influence of solar/geomagnetic forcing on climate variables, such as the drought index, discharge and large-scale atmospheric indices in the Danube River basin, and detected significant solar/geomagnetic forcing appears in the terrestrial variables with a delay of 2-3 years, and the results of testing the response of large scale climate variability indices at solar/geomagnetic forcing can be found in [39].…”