Drought response analysis based on cross wavelet transform and mutual entropy

Li, Yanling; Wen, Yunliang; Lai, Hexin; Zhao, Qiqi

doi:10.1016/j.aej.2020.01.050

Cited by 25 publications

(11 citation statements)

References 17 publications

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“…The multitaper spectral analysis method (MTM, Therrell et al, 2006) was used to principal major cycles. We also used the cross wavelet transform (XWT) method (Li et al, 2020) to verify long‐term relationships with the ENSO reconstruction data (Li et al, 2013; McGregor et al, 2010; Stahle et al, 1998). Pearson correlation approach was used to test the mutual response.…”

Section: Methodsmentioning

confidence: 99%

Streamflow reconstruction in the Kafirnigan River, Tajikistan since 1568 CE reveals a linkage between southern Central Asian hydrological variation and ENSO

Zulfiyor

Opała‐Owczarek

Chen

et al. 2023

Intl Journal of Climatology

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Long‐term hydroclimate change can provide reliable reference for water resources management in Central Asia. However, only a few palaeohydrological records exist in Tajikistan. To obtain a long‐term perspective on hydrological changes in Tajikistan, we developed, for the first time, a streamflow reconstruction from September of the previous year to June of the current one in the Kafirnigan River basin, based on Juniperus semiglobosa tree‐ring width indices from the Iskanderkul area in northern Tajikistan. The streamflow reconstruction explains 40% of the actual streamflow variance during the period 1939–1993. Spatial correlation analyses with gridded precipitation data indicate that our streamflow reconstruction contains a strong regional hydroclimatic signal for southern Central Asia. The high and low intervals of our streamflow reconstruction are closely related to the interdecadal variations of El Niño‐Southern Oscillation (ENSO). Our reconstructed streamflow is significantly correlated with sea surface temperatures in the eastern equatorial Pacific Ocean and northern Indian Ocean, indicate the existence of remarkable 11‐, 5.6–5.7‐, 4.3‐, 2.6‐, 2.3‐ and 2.0‐year cycles, and suggest a relationship between southern Central Asian streamflow variations and ENSO activity.

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Section: Methodsmentioning

confidence: 99%

Streamflow reconstruction in the Kafirnigan River, Tajikistan since 1568 CE reveals a linkage between southern Central Asian hydrological variation and ENSO

Zulfiyor

Opała‐Owczarek

Chen

et al. 2023

Intl Journal of Climatology

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“…It has been widely used in the fields of meteorology, climate and geophysics. For two time series and the cross wavelet power spectrum is as follows (Labat, 2010;Li et al, 2020):…”

Section: Cross Wavelet Transformmentioning

confidence: 99%

“…However, earlier studies have not used CWT and DWT together to study both GIC and geomagnetic data. Moreover, the cross-wavelet technique can analyze the correlation between the high-energy and low-energy regions of two time series in the time-frequency domain from multiple time scales, reflecting the phase structure of the two; and it has been widely used in geography and physics (Li et al, 2020). However Earlier studies not analyzed the correlation between GIC and geomagnetic data using crossed wavelets.…”

Section: Introductionmentioning

confidence: 99%

Spectral analysis of geomagnetically induced current and local magnetic field during the 17 March 2013 geomagnetic storm

Zou

Balan

et al. 2022

Advances in Space Research

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“…The wavelet power spectrum can be used to state the mutation features and multiscale evolution of time series and sequences. The equation of the wavelet power spectrum can be mentioned as [63]:…”

Section: Wavelet Transform (Wt)mentioning

confidence: 99%

Evaluating Drought Events by Time-Frequency Analysis: A Case Study in Aegean Region of Turkey

2021

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Drought is a slowly progressing and complex natural phenomenon, so the nature of drought events remains unclear. Remote sensing is preferred as an effective tool for finding, evaluating, and monitoring drought especially for large areas throughout long-term periods by providing near real-time and accurate data. Besides, Google Earth Engine (GEE) is a cloud-based service to provide analysis and visualization of geospatial datasets. The ability of GEE as a remote sensing platform to analyze high-impact societal issues , including water management diseases, disaster, deforestation, and climate monitoring environmental protection, offers it as the best option for drought monitoring. Here, Vegetation Health Index (VHI) index that combines Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) has been chosen for agricultural drought assessment in a case study (Aegean Region of Turkey) from 2000 to 2018 (19 years). Thence, the land surface temperature (LST) data and the Normalized Difference Vegetation Index (NDVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor have been used and analyzed as remotely sensed data. The major data processing steps have been efficiently done on the GEE platform . Also, the time series and periodic behavior of these satellite-based indices have been examined. Besides, as the meteorological drought index, Standardized Precipitation Evapotranspiration Index (SPEI) time series were calculated for the region in question at different time scales (SPEI3, SPEI6, SPEI12, etc.) from 1980 to 2018 (39 years). Also, the frequency analysis of both satellite-based and meteorological station-based indices has been done. Fast Fourier Transform (FFT) for satellite-based indices frequency analyzing and Wavelet Transform (WT) for time-frequency analyzing of SPEI sequence have been used. Cross Wavelet (XWT), and Coherence Wavelet (CWT) were used to evaluate the time-frequency relationship of the satellite-based and the meteorological station-based time series.

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Drought response analysis based on cross wavelet transform and mutual entropy

Cited by 25 publications

References 17 publications

Streamflow reconstruction in the Kafirnigan River, Tajikistan since 1568 CE reveals a linkage between southern Central Asian hydrological variation and ENSO

Streamflow reconstruction in the Kafirnigan River, Tajikistan since 1568 CE reveals a linkage between southern Central Asian hydrological variation and ENSO

Spectral analysis of geomagnetically induced current and local magnetic field during the 17 March 2013 geomagnetic storm

Evaluating Drought Events by Time-Frequency Analysis: A Case Study in Aegean Region of Turkey

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