DendroSync (version 0.1.4)

gen.het.aSE: Within-group synchrony for heteroscedastic mixed models

Description

The function calculates for each varGroup stratum the synchrony (a^) and standard error (SE), but only for heteroscedastic unstructured and narrow evaluation mixed models (mHeNE, mHeUN).

Usage

gen.het.aSE (model)

Arguments

model

a class "lme" model produced by dendro.varcov with homoscedastic equals FALSE.

Value

The function returns a matrix containing within-group synchrony and SE for each level of varGroup. This function is used internally in sync.

Details

The function calculates the within-group synchrony values for each varGroup stratum based on the metodology described in Shestakova et al. (2014) and Shestakova et al. (2016). Note that this function is designed to work only in heteroscedastic narrow evaluation and unstructured mixed models (ie. mHeNE and mHeUN).

References

Shestakova, T.A., Aguilera, M., Ferrio, J.P., Gutierrez, E. & Voltas, J. (2014). Unravelling spatiotemporal tree-ring signals in Mediterranean oaks: a variance-covariance modelling approach of carbon and oxygen isotope ratios. Tree Physiology 34: 819-838.

Shestakova, T.A., Gutierrez, E., Kirdyanov, A.V., Camarero, J.J., Genova, M., Knorre, A.A., Linares, J.C., Resco de Dios, V., Sanchez-Salguero, R. & Voltas, J. (2016). Forests synchronize their growth in contrasting Eurasian regions in response to climate warming. Proceedings of the National Academy of Sciences of the United States of America 113: 662-667.

See Also

sync for a clear description of synchrony evaluation.

Examples

# NOT RUN {
## Calculate within-group heterosdecastic synchrony and SE for conifersIP data:
 data(conifersIP)
 
 #Fit the heteroscedastic set of varcov models (mBE, mHeNE, mHeCS, mHeUN)
 # using taxonomic grouping criteria (i.e. Species)
 ModHt <- dendro.varcov(TRW ~ Code, varTime = "Year", varGroup = "Species", 
                        data = conifersIP, homoscedastic = FALSE)
 summary(ModHt)
   
 #Obtain the heteroscedastic within-group synchrony and SE for each varGroup stratum.
 gen.het.aSE(ModHt$mHeNE)#Narrow evaluation model
 gen.het.aSE(ModHt$mHeUN)#Unstructured model
 
# }