Climate signals in a multispecies tree-ring network from central and southern Italy and reconstruction of the late summer temperatures since the early 1700s
A first assessment of the main climatic drivers that modulate the tree-ring width (RW) and maximum latewood density (MXD) along the Italian Peninsula and northeastern Sicily was performed using 27 forest sites, which include conifers (RW and MXD) and broadleaves (only RW). Tree-ring data were co...
Main Authors: | , , , , , , , , , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-11-01
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Series: | Climate of the Past |
Online Access: | https://www.clim-past.net/13/1451/2017/cp-13-1451-2017.pdf |
Summary: | A first assessment of the main climatic drivers that modulate the
tree-ring width (RW) and maximum latewood density (MXD) along the Italian
Peninsula and northeastern Sicily was performed using 27 forest sites, which
include conifers (RW and MXD) and broadleaves (only RW). Tree-ring data were
compared using the correlation analysis of the monthly and seasonal variables
of temperature, precipitation and standardized precipitation index (SPI, used
to characterize meteorological droughts) against each species-specific site
chronology and against the highly sensitive to climate (HSTC) chronologies
(based on selected indexed individual series). We find that climate signals
in conifer MXD are stronger and more stable over time than those in conifer
and broadleaf RW. In particular, conifer MXD variability is directly
influenced by the late summer (August, September) temperature and is
inversely influenced by the summer precipitation and droughts (SPI at a
timescale of 3 months). The MXD sensitivity to August–September (AS) temperature and to summer
drought is mainly driven by the latitudinal gradient of summer precipitation
amounts, with sites in the northern Apennines showing stronger climate
signals than sites in the south. Conifer RW is influenced by the temperature
and drought of the previous summer, whereas broadleaf RW is more influenced
by summer precipitation and drought of the current growing season. The
reconstruction of the late summer temperatures for the Italian Peninsula for
the past 300 years, based on the HSTC chronology of conifer MXD, shows a stable
model performance that underlines periods of climatic cooling (and likely
also wetter conditions) in 1699, 1740, 1814, 1914 and 1938, and follows well the
variability of the instrumental record and of other tree-ring-based
reconstructions in the region. Considering a 20-year low-pass-filtered series,
the reconstructed temperature record consistently deviates < 1 °C
from the instrumental record. This divergence may also be due
to the precipitation patterns and drought stresses that influence the
tree-ring MXD at our study sites. The reconstructed late summer temperature
variability is also linked to summer drought conditions and it is valid for
the west–east oriented region including Sardinia, Sicily, the Italian
Peninsula and the western Balkan area along the Adriatic coast. |
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ISSN: | 1814-9324 1814-9332 |