Indices for daily temperature and precipitation extremes in Europe analysed for the period 1901-2000

We analyze century-long daily temperature and precipitation records for stations in
Europe west of 60
E. A set of climatic indices derived from the daily series, mainly
focusing on extremes, is defined. Linear trends in these indices are assessed over the
period 1901–2000. Average trends, for 75 stations mostly representing Europe west of
20
E, show a warming for all temperature indices. Winter has, on average, warmed more
(
1.0
C/100 yr) than summer (
0.8
C), both for daily maximum (TX) and minimum
(TN) temperatures. Overall, the warming of TX in winter was stronger in the warm tail
than in the cold tail (1.6 and 1.5
C for 98th and 95th, but
1.0
C for 2nd, 5th and 10th
percentiles). There are, however, large regional differences in temperature trend
patterns. For summer, there is a tendency for stronger warming, both for TX and TN, in
the warm than in the cold tail only in parts of central Europe. Winter precipitation totals,
averaged over 121 European stations north of 40
N, have increased significantly by

12% per 100 years. Trends in 90th, 95th and 98th percentiles of daily winter
precipitation have been similar. No overall long-term trend occurred in summer
precipitation totals, but there is an overall weak (statistically insignificant and regionally
dependent) tendency for summer precipitation to have become slightly more intense but
less common. Data inhomogeneities and relative sparseness of station density in many
parts of Europe preclude more robust conclusions. It is of importance that new methods
are developed for homogenizing daily data.