Artículos Científicos

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https://hdl.handle.net/20.500.12748/588

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700,000 years of tropical Andean glaciation
(Nature, 2022-07-13) Rodbell, D. T.; Hatfield, R. G.; Abbott, M. B.; Tapia, P. M.
Este estudio proporciona un registro continuo e independiente de glaciaciones tropicales en los Andes, basado en un núcleo de pistón extraído del lago Junín, ubicado en la cuenca superior del Amazonas. El núcleo abarca un periodo de 700,000 años y ofrece una visión única de los ciclos glaciales e interglaciales tropicales. Los hallazgos revelan que los glaciares tropicales en los Andes respondieron de manera sincronizada a los cambios en el volumen de hielo global, siguiendo una periodicidad de aproximadamente 100,000 años, similar a la observada en otras regiones del planeta. Este registro continuo ofrece nuevos insights sobre las teleconexiones climáticas que han impulsado los ciclos de glaciación en los trópicos, proporcionando una base valiosa para comparaciones interhemisféricas más detalladas y para la comprensión de los patrones climáticos a largo plazo en la región andina.
Characteristics of cloud properties over South America and over Andes observed using CloudSat and reanalysis data
(International Journal of Remote Sensing, 2023-04-11) Shailendra Kumar; Jose Luis Flores; Aldo S. Moya-Álvarez; Daniel Martinez-Castro; Yamina Silva
CloudSat profile of attenuated corrected radar reflectivity (Ze) and cloud mask data are used to investigate the cloud properties over South America (SA) during Austral Summer monsoon seasons. Deep convective core (DCC), deep & intense convective systems (DCSs & ICSs), and cloud clusters (CCs) are defined based on the Ze and cloud mask values. The spatial distributions of DCCs show that land-dominated areas have higher frequency of DCCs and Atlantic Ocean has less DCCs. The Pacific Ocean does not consist of DCCs, whereas eastern flank of Andes has higher frequency of DCCs compared to western flank of the Andes. North La Plata basin (Sierra de Cordoba) has a higher fraction of deeper (shallower) DCCs. Deep convection over the Sierra de Cordoba and South La Plata Basin is characterized by precipitation-size particles compared to cloud-size particles, whereas deep convection over north La Plata Basin is dominated by mostly cloud-size particles. The horizontal span of DCSs and ICSs is higher over south La Plata Basin and Atlantic Oceans compared to other SA areas. Sierra de Cordoba (Atlantic Ocean) has the highest (lowest) frequency of small DCSs and vice versa. DCSs and ICSs show the opposite characteristic, as all the selected areas consist of a higher fraction of large (small) sized DCSs (ICSs). CCs develop more in horizontal than in vertical direction over the high latitude and vice versa over lower latitude. The CCs distribution reflects the orography and moisture flow pattern at the east and west side of Andes. The higher Ze, which is the proxy for rainfall, occurs at the eastern flank/slope of the Andes, and related to easterly moisture loaded synoptic flow, transported from Amazon and upslope flow along the slope.
Contemporary glacial lakes in the Peruvian Andes
(World Wide, 2021-07) J.L.Wood; S. Harrison; A.Emmer; C.Yarleque; F.Glassere; J.C.Torres; A.Caballero; J.Araujo; G.L.Bennetta; A.Diaz-Moreno; D.Garay; H.Jara; C.Pomag; J.M.Reynolds; C.A.Riveros; E.Romerod; S.Shannoni; T.Tinoco; E.Turpo; H.Villafane
Glacier recession in response to climate warming has resulted in an increase in the size and number of glacial lakes. Glacial lakes are an important focus for research as they impact water resources, glacier mass balance, and some produce catastrophic glacial lake outburst floods (GLOFs). Glaciers in Peru have retreated and thinned in recent decades, prompting the need for monitoring of ice- and water-bodies across the cordilleras. These monitoring efforts have been greatly facilitated by the availability of satellite imagery. However, knowledge gaps remain, particularly in relation to the formation, temporal evolution, and catastrophic drainage of glacial lakes. In this paper we address this gap by producing the most current and detailed glacial lake inventory in Peru and provide a set of reproducible methods that can be applied consistently for different time periods, and for other mountainous regions. The new lake inventory presented includes a total of 4557 glacial lakes covering a total area of 328.85 km2. In addition to detailing lake distribution and extent, the inventory includes other metrics, such as dam type and volume, which are important for GLOF hazard assessments. Analysis of these metrics showed that the majority of glacial lakes are detached from current glaciers (97%) and are classified as either embedded (i.e. bedrock dammed; ~64% of all lakes) or (moraine) dammed (~28% of all lakes) lakes. We also found that lake size varies with dam type; with dammed lakes tending to have larger areas than embedded lakes. The inventory presented provides an unparalleled view of the current state of glacial lakes in Peru and represents an important first step towards (1) improved understanding of glacial lakes and their topographic and morphological characteristics and (2) assessing risk associated with GLOFs. Keywords: Hazard; Glacier; Lake; GLOF; Climate; Method

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