@article{eprints2362,
            year = {2012},
           title = {Natural variability and anthropogenic effects in a Central Mediterranean core},
          number = {2},
           pages = {831--839},
           month = {April},
          volume = {8},
          author = {Silvia Alessio and Gianna Vivaldo and Carla Taricco and Michael Ghil},
       publisher = {European Geosciences Union},
         journal = {Climate of the Past },
        abstract = {We evaluate the contribution of natural variability to the modern decrease in foraminiferal {\ensuremath{\delta}}18O by relying on a 2200-yr-long, high-resolution record of oxygen isotopic ratio from a Central Mediterranean sediment core. Pre-industrial values are used to train and test two sets of algorithms that are able to forecast the natural variability in {\ensuremath{\delta}}18O over the last 150 yr. These algorithms are based on autoregressive models and neural networks, respectively; they are applied separately to each of the {\ensuremath{\delta}}18O series' significant variability components, rather than to the complete series. The separate components are extracted by singular-spectrum analysis and have narrow-band spectral content, which reduces the forecast error. By comparing the sum of the predicted low-frequency components to its actual values during the Industrial Era, we deduce that the natural contribution to these components of the modern {\ensuremath{\delta}}18O variation decreased gradually, until it reached roughly 40\%, as early as the end of the 1970s.},
             url = {http://eprints.imtlucca.it/2362/}
}