Table A.6.

Part 1 of the list of symbols and notations used in this paper.

Symbol	Description
$X_t$, $W_t$	time series
$m$	number of ensembles in EEMD
$s$	number of IMFs to be extracted from $X_t$ or $W_t$
$k$	variable that specifies an ensemble in a given iteration of EEMD
$n$	number of meteorological and human mobility variables
$Y_1,\dots ,Y_n$	meteorological and human mobility variables
$Z_t$	time series obtained from $W_t$
${\sigma }_{\mathit{original}}$	standard deviation of $X_t$
${\sigma }_{\mathit{noise}}$	standard deviation of $Z_t$
$\mu$	a relatively small number which relates ${\sigma }_{\mathit{noise}}$ and ${\sigma }_{\mathit{original}}$
$e_{\mathit{max}}^k$	upper envelope of $X_t$
$e_{\mathit{min}}^k$	lower envelope of $X_t$
$m_t^k$	time series which correspond to average between $e_{\mathit{max}}^k$ and $e_{\mathit{min}}^k$
$d_t^k$	time series obtained by the operation $d_t^k=Z_t-m_t^k$
${\text{IMF}}_j^k$	$j$-th IMF of ensemble $k$
${\mathrm{IMF}}_{{\mathrm{X}}_{\mathrm{t}}}^{\mathrm{j}}$	$j$-th IMF obtained from the time series $X_t$
${\mathrm{IMF}}_{{\mathrm{Y}}_{\mathrm{t}}}^{\mathrm{j}}$	$j$-th IMF obtained from the time series $Y_t$
${\mathrm{RES}}_{Y_j}^{}$	residual values found by applying EEMD to $Y_j$
${\widehat{\mathrm{IMF}}}^j$	$j$-th IMF of the estimated time series
$\widehat{\mathrm{Res}}$	estimated residual values
${\widehat{X}}_t$	time series ${\widehat{X}}_t={\widehat{\mathrm{IMF}}}^1+\dots +{\widehat{\mathrm{IMF}}}^s+\widehat{\mathrm{Res}}$
$\rho$	Spearman correlation coefficient