SOO-year Winter Temperature and Precipitation
Variability over
Connection to
Circulation
the Mediterranean Area and its
the Large-scale Atmospheric
J. Luterbacher and E. Xoplaki
Summary
Spatio-temporal highly resolved estimates of past natural climate variability
over the Mediterranean are important to assess recent significant climate
trends. Principal component regression analysis has been performed to
reconstruct monthly (AD 1659-1900) and seasonal (AD 1500-1658)
temperature and precipitation fields over the land areas including Europe,
North Africa and the Near East (Luterbacher et al. 200lc). The
reconstructions are based on the combination of early instrumental station
series (temperature, pressure and precipitation) and proxy reconstructions
from Eurasian sites. The statistical relationships were deri ved over the 19011990 period and were applied to the available data prior to 1900 in order to
derive the temperature and precipitation reconstructions back to AD 1500.
We derived a winter mean Mediterranean precipitation and temperature
time series from AD 1500-1995 through averaging 2159 gridpoints over the
larger Mediterranean area (lOcW-40'E; 30N-47N). Several cold relapses
and warm intervals as well as dry and wet periods on the decadal timescale,
on which shorter-period quasi-oscillatory behaviour was superimposed,
could be shown.
1891 was the coldest, 1772 the warmest, 1609 the driest and 1684 the
wettest Mediterranean winter over the last few centuries. The corresponding
connected sea level pressure (SLP) fields are analysed and compared with
the long-term 20 th century mean. The potential and the limitations of these
reconstructions are presented.
A negative highly signiticant correlation has been found between the
winter North Atlantic Oscillation Index (NAOI) and winter Mediterranean
precipitation, but only a weak connection between the NAOI and
Mediterranean temperature.
Variability over
Connection to
Circulation
the Mediterranean Area and its
the Large-scale Atmospheric
J. Luterbacher and E. Xoplaki
Summary
Spatio-temporal highly resolved estimates of past natural climate variability
over the Mediterranean are important to assess recent significant climate
trends. Principal component regression analysis has been performed to
reconstruct monthly (AD 1659-1900) and seasonal (AD 1500-1658)
temperature and precipitation fields over the land areas including Europe,
North Africa and the Near East (Luterbacher et al. 200lc). The
reconstructions are based on the combination of early instrumental station
series (temperature, pressure and precipitation) and proxy reconstructions
from Eurasian sites. The statistical relationships were deri ved over the 19011990 period and were applied to the available data prior to 1900 in order to
derive the temperature and precipitation reconstructions back to AD 1500.
We derived a winter mean Mediterranean precipitation and temperature
time series from AD 1500-1995 through averaging 2159 gridpoints over the
larger Mediterranean area (lOcW-40'E; 30N-47N). Several cold relapses
and warm intervals as well as dry and wet periods on the decadal timescale,
on which shorter-period quasi-oscillatory behaviour was superimposed,
could be shown.
1891 was the coldest, 1772 the warmest, 1609 the driest and 1684 the
wettest Mediterranean winter over the last few centuries. The corresponding
connected sea level pressure (SLP) fields are analysed and compared with
the long-term 20 th century mean. The potential and the limitations of these
reconstructions are presented.
A negative highly signiticant correlation has been found between the
winter North Atlantic Oscillation Index (NAOI) and winter Mediterranean
precipitation, but only a weak connection between the NAOI and
Mediterranean temperature.