The Medieval Climate Anomaly and the Little Ice Age in the eastern Ecuadorian Andes

• DOI: 10.5194/cp-9-307-2013
• Publication Date: 2013-02-05T09:45:31Z
• Authors: M.-P. Ledru; V. Jomelli; P. Samaniego; M. Vuille; S. Hidalgo; M. Herrera; C. Ceron
• Keywords: Anomaly (physics)

Abstract. To better characterize the climate variability of last millennium in high Andes, we analyzed pollen content a 1150-yr-old sediment core collected bog located at 3800 m a.s.l. páramo eastern Cordillera Ecuador. An upslope convective index based on ratio between cloud transported from Andean forest to (T) and Poaceae frequencies, related edaphic moisture (P), was defined. This used distinguish changes atmospheric soil their associated patterns interdecadal El Niño–Southern Oscillation (ENSO) South American summer monsoon (SASM) activity. Results show that 850 1250 AD, Medieval Climate Anomaly interval warm moist with pollen/Poaceae (T/P) linked ENSO weak SASM Between 1550 dry prevailed, characterized by an abrupt decrease T/P therefore no convection, lower significant impact floristic composition páramo. During Little Ice Age, two phases were observed: first, wet phase 1750 AD low Pacific south equatorial Atlantic sea surface temperatures (SSTs) favored return páramo, then cold 1800 activity resulted drying The current period marks beginning – highest weaker modifying water storage Our results is progressively losing its capacity for both tropical SSTs matter patterns, although many teleconnection mechanisms are still poorly understood.