Vector wavelet coherence for multiple time series

Oygur, Tunc; Ünal, Gazanfer

doi:10.1007/s40435-020-00706-y

Cited by 20 publications

(6 citation statements)

References 11 publications

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“…Given this study’s time-dependency and non-stationarity of the dengue and climatic data, we recognized the need for a specialized clustering analysis approach. To address these challenges, we utilized a methodology based on vector wavelet coherence, introduced by Oygur and Unal [ 38 ]. This approach provides a means to assess the synchronicity and co-movements between various climatic time series and dengue data.…”

Section: Methodsmentioning

confidence: 99%

Common patterns between dengue cases, climate, and local environmental variables in Costa Rica: A wavelet approach

García,

Chou-Chen,

Barboza

et al. 2023

PLOS Glob Public Health

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Dengue transmission poses significant challenges for public health authorities worldwide due to its susceptibility to various factors, including environmental and climate variability, affecting its incidence and geographic spread. This study focuses on Costa Rica, a country characterized by diverse microclimates nearby, where dengue has been endemic since its introduction in 1993. Using wavelet coherence and clustering analysis, we performed a time-series analysis to uncover the intricate connections between climate, local environmental factors, and dengue occurrences. The findings indicate that multiannual dengue frequency (3 yr) is correlated with the Oceanic Niño Index and the Tropical North Atlantic Index. This association is particularly prominent in cantons located along the North and South Pacific Coast, as well as in the Central cantons of the country. Furthermore, the time series of these climate indices exhibit a leading phase of approximately nine months ahead of dengue cases. Additionally, the clustering analysis uncovers non-contiguous groups of cantons that exhibit similar correlation patterns, irrespective of their proximity or adjacency. This highlights the significance of climate factors in influencing dengue dynamics across diverse regions, regardless of spatial closeness or distance between them. On the other hand, the annual dengue frequency was correlated with local environmental indices. A persistent correlation between dengue cases and local environmental variables is observed over time in the North Pacific and the Central Region of the country’s Northwest, with environmental factors leading by less than three months. These findings contribute to understanding dengue transmission’s spatial and temporal dynamics in Costa Rica, highlighting the importance of climate and local environmental factors in dengue surveillance and control efforts.

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Section: Methodsmentioning

confidence: 99%

Common patterns between dengue cases, climate, and local environmental variables in Costa Rica: A wavelet approach

García,

Chou-Chen,

Barboza

et al. 2023

PLOS Glob Public Health

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“…We performed all analyses using R Statistical Software (R Core Team, 2021). We built linear regression models using nlme , forecast and orcutt packages and used the WaveletComp and vectorwavelet packages to conduct wavelet analyses (Bates et al, 2021; Hyndman et al, 2021; Oygur et al, 2021; Roesch & Schmidbauer, 2018; Stefano et al, 2018).…”

Section: Methodsmentioning

confidence: 99%

Poleward shifts and altered periodicity in boreal bird irruptions over six decades

Widick

Young

LaMontagne

et al. 2023

Journal of Animal Ecology

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1. Range boundaries are long-term biogeographic features of species distributions and abundance. However, many species demonstrate dynamic range boundaries, reflecting strong seasonal and annual variability in migratory behaviour. 2. As a form of facultative migration, irruptions involve the movement of many individuals outside of their resident range in response to climate variability, resource availability, and demographic processes. Many species have experienced range shifts and altered phenology in response to modern climate change, but spatiotemporal changes in irruption dynamics are less well known. 3. We quantified changes in the geography and periodicity of boreal bird irruptions across eastern North America from 1960 to 2021. Using data from Audubon's Christmas Bird Count for nine finch species, including several exhibiting recent population declines, we evaluated latitudinal trends in southern range and irruption boundaries and characterized irruption periodicity using spectral wavelet analysis. 4. Six boreal birds exhibited significant northward shifts in their southern range boundaries and three species displayed shifts in their southern irruption boundaries. 5. Irruption periodicity across multiple species was consistent across the 1960s and 1970s, culminating in frequent and synchronized irruptions of multiple species (superflights) during earlier decades. Coherence between species dampened beginning in the early 1980s as superflight periodicity became increasingly unstructured, finally reforming in recent decades, after 2000. 6. Boreal birds are considered important sentinels of the boreal forests, and northward shifts and altered periodicity of irruptions may indicate broad-scale changes in climate-and resource-associated drivers operating across the boreal forests.

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“…Multiple wavelet coherence was also conducted between EDFD, SMPD, and NINO3.4 time series indexes to further investigate the interaction with ENSO and severe FD. Multiple wavelet coherence can calculate a wavelet coherence with an n‐dimensional vector and also computes a continuous wavelet transform similar to biwavelet coherence (Oygur & Unal, 2020). Wavelet coherence(s) were performed using the R packages biwavelet and vectorwavelet with 50,000 and 10,000 Monte Carlo simulations respectively (Gouhier et al., 2021).…”

Section: Methodsmentioning

confidence: 99%

Trends, Variability, and Drivers of Flash Droughts in the Contiguous United States

Lesinger

Tian

2022

Water Resources Research

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Flash droughts (FDs) are extreme climate phenomena occurring at the subseasonal timescale, which have significant impacts on our society. Traditional droughts are considered long-lasting and long-developing events and cause severe hydrologic imbalances in both natural and managed systems (Mishra & Singh, 2010) whereas FDs are more recently identified by their rapid onset and intensification at shorter time scales (L.

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Vector wavelet coherence for multiple time series

Cited by 20 publications

References 11 publications

Common patterns between dengue cases, climate, and local environmental variables in Costa Rica: A wavelet approach

Common patterns between dengue cases, climate, and local environmental variables in Costa Rica: A wavelet approach

Poleward shifts and altered periodicity in boreal bird irruptions over six decades

Trends, Variability, and Drivers of Flash Droughts in the Contiguous United States

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