Rain in Spain is on the decline

February 2, 2011

A study led by the University of Zaragoza (UNIZAR) has studied precipitation trends in Spain's 10 hydrological basins over the 1946 to 2005 period. The results show that precipitation has declined overall between the months of March and June, reducing the length of the rainy season. The rains are heavier in October in the north west of the country.

Since 1946, the average precipitation falling on Spanish hydrological basins has undergone "notable" changes. The researchers observed a widespread decline in March and June, above all in March (except in the basin of the Segura), with less intense rains in June.

"The basin of the Guadiana (in the south west of ) has experienced the strongest downward trend, with a reduction of 18%, while the positive trends recorded in the north west of the peninsula were less intense (the Norte, Douro and Tagus basins)", José Carlos González-Hidalgo, lead author of the study and a researcher at the UNIZAR, tells SINC.

The study, which has been published in the journal Climate Research, shows that the decline in rainfall in March leads to a reduction in the duration of the wet season. Even with the trend recorded in October (increased precipitation), the total precipitation for the hydrological year is increasingly dependent on the onset of the wet season. "In other words, it seems that the wet season has become shorter", explains González-Hidalgo.

Understanding what is happening in the basins

The research team studied the precipitation changes in each Spanish basin, and analysed the monthly series using the running trend technique, which "calculates the precipitation trend for various successive years, looks at the changes that have taken place, and detects possible modifications in this trend", the scientist explains.

Water is the most important resource in Spain, and it is managed by national water planning units at local level within the hydrological basins. "In order to plan the most effective way of using water, it is of fundamental importance to know what has happened in these basins, and what is happening now," the professor from the UNIZAR Department of Geography explains.

The data used to produce the study come from MOPREDAS, the most complete monthly precipitation database in mainland , produced by the Department of Geography of the UNIZAR.

The UNIZAR researchers, working with the Czech Hydrometeorological Institute and the Institute of Atmospheric and Climate Science of Bologna (Italy), used all the records preserved in the archives of the Spanish State Meteorology Agency (AEMET).

Explore further: Intense precipitation expected worldwide

Related Stories

Intense precipitation expected worldwide

October 13, 2005

Scientists at the National Center for Atmospheric Research in Boulder, Colo., say global warming will produce more intense precipitation around the world.

Rainfall to decrease over Iberian Peninsula

July 23, 2009

Scientists have recorded a decline in winter precipitation over the past 60 years in Spain, and they now forecast that precipitation will also decrease in spring and summer. A team from the Pyrenean Institute of Ecology (CSIC) ...

The Sur, Baleares and Segura basins are the driest in Spain

January 27, 2010

There is some discrepancy among the scientific community as to the situation of reservoirs in Spain, one of the countries with the greatest water stress in Europe. For this purpose, a team of researchers has surveyed experts ...

Recommended for you

Don't forget plankton in climate change models, says study

November 26, 2015

A new study from the University of Exeter, published in the journal Ecology Letters, found that phytoplankton - microscopic water-borne plants - can rapidly evolve tolerance to elevated water temperatures. Globally, phytoplankton ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.