Temperature and Precipitation Variability and
Trends in Northern Spain
Iberian Peninsula Climate
in the Context of the
MJ. Esteban-Parra, D. Pozo-Vazquez, F.S. Rodrigo, Y. Castro-Dfez
Abstract
The longest precipitation and temperature series of the peninsular Spain and
Balearic Islands are analysed covering the periods 1880-1995 and 1900-1997
respectively. To identify coherent behaviour in these series, the PCA method
has been used, resulting in several major noise-filtered time series. For
temperature data, although two statistically significant EOFs have been
obtained for the western and eastern parts of Spain, the entire region can be
described by one EOF and its time evolution by the first PC series. These time
series show a general upward trend and some abrupt changes. On the other
hand, for precipitation, we have obtained three significant EOFs, except for
winter, when we find four EOFs. The first EOF can be associated with
Andalusia and Spanish Interior, the second and third EOFs with
Mediterranean and Cantabric coasts, alternatively, depending on the season.
The analysis of the principal components series using moving average and the
Mann-Kendall test, show significant long term decreases in precipitation for
Mediterranean region and Interior (at least in some seasons) and an increase
of the precipitation for the Northern coastal region. The changes found have
been related to changes in the circulation patterns and discussed from the
perspective of climatic change.
KEYWORDS: Mean temperature, precipitation Spain, PCA, climatic change.
1 Introduction
The most common variable analyzed to assess climatic change due to increased
greenhouse gases in the atmosphere is the average global temperature. The series of
this variable present a significant rise during the period of instrumental records, by
more than 0.6 °C over the past 135 years (Jones et aI., 1994). This variable, the
Trends in Northern Spain
Iberian Peninsula Climate
in the Context of the
MJ. Esteban-Parra, D. Pozo-Vazquez, F.S. Rodrigo, Y. Castro-Dfez
Abstract
The longest precipitation and temperature series of the peninsular Spain and
Balearic Islands are analysed covering the periods 1880-1995 and 1900-1997
respectively. To identify coherent behaviour in these series, the PCA method
has been used, resulting in several major noise-filtered time series. For
temperature data, although two statistically significant EOFs have been
obtained for the western and eastern parts of Spain, the entire region can be
described by one EOF and its time evolution by the first PC series. These time
series show a general upward trend and some abrupt changes. On the other
hand, for precipitation, we have obtained three significant EOFs, except for
winter, when we find four EOFs. The first EOF can be associated with
Andalusia and Spanish Interior, the second and third EOFs with
Mediterranean and Cantabric coasts, alternatively, depending on the season.
The analysis of the principal components series using moving average and the
Mann-Kendall test, show significant long term decreases in precipitation for
Mediterranean region and Interior (at least in some seasons) and an increase
of the precipitation for the Northern coastal region. The changes found have
been related to changes in the circulation patterns and discussed from the
perspective of climatic change.
KEYWORDS: Mean temperature, precipitation Spain, PCA, climatic change.
1 Introduction
The most common variable analyzed to assess climatic change due to increased
greenhouse gases in the atmosphere is the average global temperature. The series of
this variable present a significant rise during the period of instrumental records, by
more than 0.6 °C over the past 135 years (Jones et aI., 1994). This variable, the