SPATIO-TEMPORAL VARIATIONS IN HYDROCLIMATE ACROSS THE MEDITERRANEAN ANDES (30-37°S) SINCE THE EARLY 20TH CENTURY

CARLOS LE QUESNE; VILLALBA RICARDO; SEBASTIAN CRESPO; ALVARO GONZALEZ REYES; DUNCAN CHRISTIE; JAMES MCPHEE; PAUL SZEJNER; MARIANO MASIOKAS; ARIEL MUÑOZ

JOURNAL OF HYDROMETEOROLOGY

AMER METEOROLOGICAL SOC

Lugar: Boston; Año: 2017

1525-755X

In the Mediterranean Andes (MA; 30ºS - 37ºS) the main rivers are largely fed by the41 snowmelt from the Andes and provide fresh water to around 10 million people on both42 sides of the Cordillera. Water resources in the MA are under intense human pressure due43 to the extensive development of agro-industrial and mining activities. Presently, the MA44 region faces one of the most severe droughts recorded during the instrumental period.45 Previous studies have identified ENSO as the main forcing controlling the interannual46 hydroclimate variability of the MA, however, the role of decadal and multidecadal47 climate variability, their spatial patterns and the recurrence long-term droughts, remain48 poorly studied. In this contribution, spatial and temporal patterns of the MA49 hydroclimatic variability are analyzed using an extensive and high quality database of50 streamflow, precipitation, and winter snowpack covering the 1910 ? 2011 interval. Based51 on the combination of correlation, principal components, spectral and kernel-estimation52 techniques, two hydroclimatic sub-regions are identified in the MA, located north and53 south of 34ºS. The interannual variability associated with ENSO, although present in both54 regions, is stronger north of 34ºS. In contrast, decadal to multi-decadal variability55 associated with the PDO and/or IPO, also recorded in both regions, is more marked south56 of 34ºS. Kernel estimation of droughts occurrence rate reveals an increase of dry57 conditions since the 1950s in both sub-regions.