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WP 1.4 Paleoclimatic data from mountain and continental regions

Task 1. Collection and quality control of paleoclimate data

Ice core drilling data: Completion of climate and environmental records from the Lys and Ortles ice cores and comparison with data from other Alpine ice cores.

Lakes and peat bog data: Extrusion, sampling and CS-XRF analysis of lake sediment cores for age dating (210Pb and 14C). Extrusion and dating (14C) of the basal section of peat bog cores of Danta di Cadore. Calibration between isotopic ratios in precipitation and in high altitude sphagnum bogs, as functions of the main meteo-climatic variables. Definition of an accurate dating for two peat cores (Danta di Cadore and Coltrondo), the Ortles ice core and four lake sediment cores.

Palynological data: The stratigraphic and palynological database will be populated with the collected data and metadata. Palynological data will be used to reconstruct the history of vegetation in northern Italy for the last 3000 years. The palynological analysis in Danta di Cadore and Coltrondo peat cores will be performed.  For the Danta di Cadore cores, the work will focus mainly on the samples related to the last 2000 years. For the Coltrondo cores, the resolution of the layers will be increased and deeper layers (>2000 years) will be analyzed.

Dendrochronology: the Nextdata database will be updated with new metadata and new chronologies collected by new project partners. For the new master ring-width chronologies and for the chronologies of other measured parameters (density, stable isotopes) the quality of the dendroclimatic signal will be tested and their integration in the database will be evaluated. The climate reconstructions will be carried out also for those portions of the Alpine territory where dendrochronological or climatic data show a non-optimal coverage (e.g., remote Alpine areas), as well as for the Apennines and the Mediterranean areas. Considering the complex interactions between climate and tree growth, the analysis of the recorded climatic signal will be as accurate as possible.

The construction of stable isotope chronologies from significant sites and from sub-fossil trunks will be performed in order to assess the type of climatic signal recorded at secular scale and to obtain additional climate reconstructions. The extension of chronologies from sub-fossil trunks will be accomplished also in collaboration with the University of Milan and the University of Pisa.

Task 2. Definition of transfer functions

Extension back in time of the decennial climate reconstructions and comparison of data with the instrumental or modeled climate series for the definition of the proxy-climate transfer functions. Reconstruction of paleo-temperatures from the Coltrondo and Danta di Cadore cores. Reconstructions of temperature and precipitation data from dendrochronological information.

Assessment of consistency with the available reconstructions and with the high-resolution climatology for the Italian mountains (D1.1.C).

Task 3. Construction of paleoclimate maps over the last 2000 years

Realization of an Alpine climate summary supplemented by the production of climate maps over the last 2000 years of Northern Italy derived from the integration of series of the proxy data selected by the NextData project. Paleoclimate reconstructions will be carried out by means of transfer functions applied to pollen series selected by the NextData project (Task 2). The processed data will be compared and integrated with other available climate proxies in order to perform a multiproxy paleoclimate reconstruction.