Coupled Biospheric Synchrony of the Coastal Temperate Ecosystem in Northern Patagonia: A Remote Sensing Analysis

Lara, Carlos; Cazelles, Bernard; Saldías, Gonzalo S.; Flores, Raúl P.; Paredes, Álvaro L.; Broitman, Bernardo R.

doi:10.3390/rs11182092

Cited by 7 publications

(12 citation statements)

References 67 publications

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“…When coupled with climate effects (e.g., warming), these intense drought periods could promote fire activity (frequency and severity), mainly in areas with extensive plantations of non-native forests, native sclerophyll forests, and scrublands, vegetation types that largely determine the primary productivity patterns in central Chile [37,65]. While in northern Patagonia, both coastal ocean and land biological processes are forced by climatic variability over multiple temporal scales [66].…”

Section: Discussionmentioning

confidence: 99%

“…According to Marshall [68], the SAM oscillation is defined by the gradient between the high-pressure belt at medium latitudes and the lower pressures around coastal Antarctica. As such, it is calculated as the zonally averaged pressure difference between 40 • S and 65 • S. SAM oscillations are phase-dependent with ENSO, e.g., when a positive phase of ENSO (El Niño) coincide with a negative phase of SAM (Figure A2), climate anomalies dominate south of 40 • S [69], generating extreme conditions due to high solar irradiation and reduced precipitation [66,70]. Such phaselocking could drive part of the observed changes in phenological activity, e.g., weak amplitude (see Figure 7).…”

Section: Discussionmentioning

confidence: 99%

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Climatic Regulation of Vegetation Phenology in Protected Areas along Western South America

et al. 2021

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Using 19 years of remotely sensed Enhanced Vegetation Index (EVI), we examined the effects of climatic variability on terrestrial vegetation of six protected areas along southwestern South America, from the semiarid edge of the Atacama desert to southern Patagonia (30°S–51°S). The relationship between satellite phenology and climate indices, namely MEI (Multivariate ENSO Index), PDO (Pacific Decadal Oscillation) and SAM (Southern Annular Mode) were established using statistical analyses for non-stationary patterns. The annual mode of phenological activity fluctuated in strength through time from the semiarid region to the border of southern Patagonia. Concomitantly, enhanced synchrony between EVI and climatic oscillations appeared over interannual cycles. Cross correlations revealed that variability in MEI was the lead predictor of EVI fluctuations over scales shorter than 4 months at lower latitudes and for the most poleward study site. The PDO was correlated with EVI over lags longer than 4 months at low latitude sites, while the SAM showed relationships with EVI only for sites located around 40°S. Our results indicate that the long-term phenological variability of the vegetation within protected areas along southwestern South America is controlled by processes linked to climate indices and that their influence varies latitudinally. Further studies over longer time scales will be needed to improve our understanding the impacts of climate change on vegetation condition and its effect over phenological variability.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Climatic Regulation of Vegetation Phenology in Protected Areas along Western South America

et al. 2021

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“…This iterative method is not appropriate, however, to analyze series more than three times and gives results that need to be smoothed before interpretation. Thus, in the study of Lara et al (43), we adapted the inverse PWC method from Fourier analysis (64) to wavelet analysis. This method is based on the inversion of the spectral matrix Σ(f,t) whose elements are the cross-wavelet spectrum for the i and j time series from the n time series analyzed where S jk ( f, t) is the ( j,k) element of the inverse spectral matrix Σ −1 ( f, t) and (\jk) means all elements except the jth and the kth.…”

Section: Methodsmentioning

confidence: 99%

“…Partial correlation and partial rank correlation are commonly used in Biology in other settings (40), and partial correlation has been extended to partial autocorrelation function for the analysis of time series (41). With the notion of partial correlation recently extended to wavelet coherence (WC) (42,43), we reanalyze a large number of time series for malaria and dengue, two dominant mosquito-borne disease threats around the globe (17). We specifically consider 197 published time series of incidence (or cases) together with the corresponding local and global climate variables (table S1) for different countries of South Asia, Central and South America, and sub-Saharan Africa.…”

Section: Introductionmentioning

confidence: 99%

Disentangling local and global climate drivers in the population dynamics of mosquito-borne infections

Cazelles,

Tian

et al. 2023

Sci. Adv.

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Identifying climate drivers is essential to understand and predict epidemics of mosquito-borne infections whose population dynamics typically exhibit seasonality and multiannual cycles. Which climate covariates to consider varies across studies, from local factors such as temperature to remote drivers such as the El Niño–Southern Oscillation. With partial wavelet coherence, we present a systematic investigation of nonstationary associations between mosquito-borne disease incidence and a given climate factor while controlling for another. Analysis of almost 200 time series of dengue and malaria around the globe at different geographical scales shows a systematic effect of global climate drivers on interannual variability and of local ones on seasonality. This clear separation of time scales of action enhances detection of climate drivers and indicates those best suited for building early-warning systems.

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“…However, in the Littoral zone, OM dominates, followed by DU and SU. example, to calculate the PWC of X1 on Y by controlling the effects of X2, X3, X4, X5 as in our case study) PWC is expressed as follows [28]:…”

Section: Partial Wavelet Coherence (Pwc)mentioning

confidence: 99%

Bivariate and Partial Wavelet Coherence analysis of aerosols impact on Global Horizontal Irradiation in Far-North and Littoral regions of Cameroon

Alotse¹,

Mamadou²,

Dembélé³

et al. 2023

J. Nig. Soc. Phys. Sci.

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This study investigated the time-frequency variability of Global Horizontal Irradiation (GHI) under clear sky conditions in Cameroon in relation to aerosol types using the wavelet transform method. For this purpose, we focused on two climatically different zones (Far North and Littoral) in Cameroon chosen because of the large difference in term of proportion in type of aerosols. From the Bivariate Wavelet Coherence (BWC) analysis, it was found in the Littoral zone (Dust DU, Organic Matter OM, Black Carbon BC, Sulfates SU) aerosols are negatively correlated with GHI at all frequencies, whereas Sea Salt (SS) aerosols are positively correlated with GHI. In the Far North zone, all aerosols are negatively correlated with GHI in the 0-8 month band but the dynamic has changed in the 8-16 month band. However, with the Partial Wavelet Coherence (PWC) analysis, we found that the correlations between GHI and each analyzed variable decreased after removing the effects of the remaining variables. Only the correlations between GHI and DU are still significant, with an average wavelet coherence (AWC) and percentage of significant coherence (PASC) values of 0.60 and 24.36% respectively. It is noteworthy with PWC analysis that the area with significant correlation between GHI and the other aerosol types except DU is very limited. This shows that their influences on GHI have already been covered by DU. The study also showed the combined effect of the analyzing variables (SS, BC, SU and OM) on GHI, since, independently as shown by the PWC, each of them is weakly correlated to GHI. However, with the BWC, the combined effect of other aerosols on BC and SU makes their influences on GHI important. The PWC and BWC implementations have been compiled by Matlab and can be accessed freely following this link (https://figshare.com/s/bc97956f43fe5734c784).

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Coupled Biospheric Synchrony of the Coastal Temperate Ecosystem in Northern Patagonia: A Remote Sensing Analysis

Cited by 7 publications

References 67 publications

Climatic Regulation of Vegetation Phenology in Protected Areas along Western South America

Climatic Regulation of Vegetation Phenology in Protected Areas along Western South America

Disentangling local and global climate drivers in the population dynamics of mosquito-borne infections

Bivariate and Partial Wavelet Coherence analysis of aerosols impact on Global Horizontal Irradiation in Far-North and Littoral regions of Cameroon

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