Climate Fact: The Rain in Spain
Five-hundred (500) years of records from Toledo (located near the center of the Iberian Peninsula, where Spain and Portugal are located) detailing daily life, weather events, and religious ceremonies meant to influence the weather, have been used to help determine historical trends in the frequency and severity of drought and rainfall in the region. Correlation with other historical data sources indicate that droughts are more frequent and more severe during positive phases of the North Atlantic Oscillation (NAO), or the periodic shift in the difference in atmospheric pressure between the Azores High (located in the North Atlantic, 950 miles due west of the Portuguese Coast) and the Icelandic Low. Positive phases of the NAO correspond to a greater pressure difference, and during these times the Azores High is stronger, which works to keep rainfall away from the peninsula. For any given time period, however, there is significant local variation across this peninsula, which is thought to be at least in part reflective of the diverse landscape there. For example, the northern and southern parts of the peninsula exhibit significant differences in their responses to global-scale atmospheric conditions, which may be due to their separation by the east-west oriented Sistema Central (Central Mountains). In southeastern Spain, since the end of the “Little Ice Age” about 150 years ago, average temperatures have risen by 2.7 degrees Fahrenheit, and total average annual rainfall in the region has fallen by 23 percent. This has corresponded to range expansions for many species that had formerly only been found in the Sahara desert south of the Mediterranean, but are now living in southeastern Spain.
Seasons: Winter, Spring, Summer, Fall
Sources: Ham, Anthony. “Pain in Spain, Lessons for All.” The Age 9 February 2007. Accessed Online 9 February 2007
