Spatio-temporal variations in hydroclimate across the Mediterranean Andes (30º-37ºS) since the early 20th century

GONZALEZ-REYES, A.; MCPHEE, J.; CHRISTIE, D.A.; LEQUESNE, C.; SZEJNER, P.; MASIOKAS, M.H.; VILLALBA, R.; MUÑOZ, A.A.; CRESPO, S.

JOURNAL OF HYDROMETEOROLOGY

AMER METEOROLOGICAL SOC

Lugar: Boston; Año: 2017 vol. 18 p. 1929 - 1942

1525-755X

In the Mediterranean Andes region (MA; 308?378S), the main rivers are largely fed by melting snowpackand provide freshwater to around 10 million people on both sides of the Andes Mountains. Water resources inthe MA are under pressure because of the extensive development of industrial agriculture and mining activities.This pressure is increasing as the region faces one of its worst recorded droughts. Previous studies havepointed to El Niño?Southern Oscillation (ENSO) as the main climatic force impacting the MA. However, therole of decadal and multidecadal climate variability, their spatial patterns, and the recurrence of long-termdroughts remains poorly studied. In an attempt to better understand these factors, spatial and temporalpatterns of hydroclimatic variability are analyzed using an extensive database of streamflow, precipitation,and snowpack covering the period between 1910 and 2011. These analyses are based on the combination ofcorrelation, principal components, and kernel estimation techniques. Despite a general common patternacross the MA, the results presented here identify two hydroclimatic subregions, located north and south of348S. While the interannual variability associated with ENSO is slightly stronger north of 348S, the variabilityassociated with the Pacific decadal oscillation (PDO) and/or the interdecadal Pacific oscillation (IPO) indexshows similar patterns in both regions. However, variations produced by the IPO forcing seem to be greater inthe southern subregion since 1975. The estimations presented here on drought recurrence reveal a generalizedincrease in dry extremes since the 1950s. These findings suggest that the northern MA is more vulnerable tochanges in hydrology and climate than the southern MA.