Hydroclimate of the Andes Part I: Main Climatic Features

Abstract

The Andes is the longest cordillera in the world and extends from northern South America to the southern extreme of the continent (from 11 • N to 53 • S). The Andes runs through seven countries and is characterized by a wide variety of ecosystems strongly related to the contrasting climate over its eastern and western sides, as well as along its latitudinal extension. This region faces very high potential impacts of climate change, which could affect food and water security for about 90 million people. In addition, climate change represents an important threat on biodiversity, particularly in the tropical Andes, which is the most biodiverse region on Earth. From a scientific and societal view, the Andes exhibits specific challenges because of its unique landscape and the fragile equilibrium between the growing population and its environment. In this manuscript, we provide an updated review of the most relevant scientific literature regarding the hydroclimate of the Andes with an integrated view of the entire Andes range. This review paper is presented in two parts. Part I is dedicated to summarize the scientific knowledge about the main climatic features of the Andes, with emphasis on mean large-scale atmospheric circulation, the Andes-Amazon hydroclimate interconnections and the most distinctive diurnal and annual cycles of precipitation. Part II, which is also included in the research topic "Connecting Mountain Hydroclimate Through the American Cordilleras," focuses on the hydroclimate variability of the Andes at the sub-continental scale, including the effects of El Niño-Southern Oscillation.

A Review of the Current State and Recent Changes of the Andean Cryosphere

“…The interaction between the main atmospheric circulation patterns and the orographic barrier of the Andes modulates the spatial and temporal distribution of solid precipitation across western South America, creating specific hydro-climatic regimes at different latitudes (Garreaud, 2009;Viale et al, 2019;Espinoza et al, 2020).…”

“…Thus in the inner tropical Andes of Ecuador, Colombia and Venezuela, humidity remains high throughout the year but two wetter seasons can be discerned in spring (October to November) during the southward passage of the ITCZ, and in autumn (April to May) when the belt of convective activity moves northward. In contrast, further south in the outer tropical Andes of Bolivia and Peru, most of the solid and liquid precipitation occurs when the ITCZ reaches these latitudes during the summer months (for more details see Espinoza et al, 2020). It is important to note, however, that the snow that falls outside of the glacier limits typically lasts for only a few days due to the high solar radiation which exists throughout the year, and thus the seasonal snow cover is almost entirely limited to the glacierized areas (Lejeune et al, 2007;Wagnon et al, 2009;Vuille et al, 2018).…”

Spatiotemporal dynamics of dengue in Colombia in relation to the combined effects of local climate and ENSO

“…Colombia's climate varies remarkably in time and space owing to its equatorial location and the temperature and rainfall gradients associated with the Andes topography. The temporal distribution of rainfall highly depends on the meridional oscillation of the Inter-Tropical Convergence Zone (ITCZ), the dynamics of three low-level jets: Chocó, Caribbean and Orinoco [75][76][77][78], changes in topography (0 to 6,000 m), the ocean-atmosphere dynamics of the Pacific, Atlantic and Caribbean Sea, the Amazon and Orinoco River basins, and strong land surface-atmosphere feedbacks [79,80]. Mean annual temperature and rainfall depends on altitude, and geographic location.…”

Uncertainty of runoff sensitivity to climate change in the Amazon River basin

“…We show that all precipitation datasets exhibit similar regional patterns of P with the highest values of annual precipitation occurring in the Colombian Amazon (northwestern region), while the lowest precipita-tion rates are depicted in Peru (western region), Bolivia (southwestern region), and some parts of Brazil (southeastern region). These observations coincide with macroclimatic factors, such as the migration of the Intertropical Convergence Zone (ITZC) and the South Atlantic Convergence Zone (SACZ), the activity of aerial rivers, and large-scale circulation patterns across South America, [70][71][72][73][74] including the Eastern Andean jet, also known as the Orinoco jet (northernmost leg of the SALJET), 75,76 and the two phases of the ENSO, 20,23,24 land surface-atmosphere interactions, 21,[77][78][79] vegetation activity, and precipitation recycling. [80][81][82] Regarding E p , we show that both E p products produce quite different spatial results.…”