Weather Observations Across the Southern Andes at 53°S

Schneider, Christoph; Glaser, Michael S.; Kilian, Rolf; Santana, Ariel; Butorovic, Nicolás; Casassa, Gino

doi:10.2747/0272-3646.24.2.97

Cited by 167 publications

(197 citation statements)

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“…[38] Precipitation at the NPI latitude ($46°S to 47.5°S) are strongly controlled by orography and the Andean Cordillera is an efficient topographic barrier leading to a decrease of annual precipitation rate from approximately 7000 mm on the Chilean coast (windward) to less than 200 mm east (leeward) of the Argentinean Andes [Carrasco et al, 2002;Schneider et al, 2003;Villalba et al, 2003]. Data previously published for NPI and SPI reveal accumulation rates of several meters of snow per year [Matsuoka and Naruse, 1999;Popovnin et al, 1999;Shiraiwa et al, 2002;Yamada, 1987].…”

Section: Snow Accumulation Rate and Wind Effectsmentioning

confidence: 99%

A promising location in Patagonia for paleoclimate and paleoenvironmental reconstructions revealed by a shallow firn core from Monte San Valentín (Northern Patagonia Icefield, Chile)

et al. 2008

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International audienceThe study of past climate variability from ice core investigations has been largely developed both in polar areas over the past decades and, more recently, in tropical regions, specifically along the South American Andes between 0° and 20°S. However a large gap still remains at mid-latitudes in the Southern Hemisphere. In this framework, a 15.3-m long shallow firn core has been extracted in March 2005 from the summit plateau of Monte San Valentín (3747 m, 46°35′S, 73°19′W) in the Northern Patagonia Icefield to test its potential for paleoclimate and paleoenvironmental reconstructions. The firn temperature is −11.9°C at 10-m depth allowing to expect well preserved both chemical and isotopic signals, unperturbed by water percolation. The dating of the core, on the basis of a multi-proxy approach combining annual layer counting and radionuclide measurements, shows that past environment and climate can be reconstructed back to the mid-1960s. A mean annual snow accumulation rate of 36 ± 3 cm year−1 (i.e., 19 ± 2 g cm−2 year−1) is inferred, with a snow density varying between 0.35 and 0.6 g cm−3, which is much lower than accumulation rates previously reported in Patagonia at lower elevations. Here, we present and discuss high-resolution profiles of the isotopic composition of the snow and selected chemical markers. These data provide original information on environmental conditions prevailing over Southern Patagonia in terms of air masses trajectories and origins and biogeochemical reservoirs. Our main conclusion is that the San Valentín site is not only influenced by air masses originating from the southern Pacific and directly transported by the prevailing west winds but also by inputs from South American continental sources from the E–NE, sometimes mixed with circumpolar aged air masses, the relative influence of these two very distinct source areas changing at the interannual timescale. Thus this site should offer a wealth of information regarding (South) Pacific, Argentinian NE–E areas and Antarctic climate variability

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Section: Snow Accumulation Rate and Wind Effectsmentioning

confidence: 99%

A promising location in Patagonia for paleoclimate and paleoenvironmental reconstructions revealed by a shallow firn core from Monte San Valentín (Northern Patagonia Icefield, Chile)

et al. 2008

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“…1a,b; ref. 6). Our multi-millennialscale Holocene SWW reconstruction is based on three marine sediment cores, one lacustrine record, and a peat-bog pollen record from different sites along the fjord system near the westernmost Strait of Magellan (∼53 • S) and from the Skyring fjord east of the Andean climate divide (Fig.…”

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Holocene changes in the position and intensity of the southern westerly wind belt

Lamy¹,

Kilian²,

Arz³

et al. 2010

Nature Geosci

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The position and intensity of the southern westerly wind belt varies seasonally as a consequence of changes in sea surface temperature. During the austral winter, the belt expands northward and the wind intensity in the core decreases. Conversely, during the summer, the belt contracts, and the intensity within the core is strengthened. Reconstructions of the westerly winds since the last glacial maximum, however, have suggested that changes at a single site reflected shifts throughout the entire southern wind belt 1-4 . Here we use sedimentological and pollen records to reconstruct precipitation patterns over the past 12,500 yr from sites along the windward side of the Andes. Precipitation at the sites, located in the present core and northern margin of the westerlies, is driven almost entirely by the wind belt 5 , and can be used to reconstruct its intensity. Rather than varying coherently throughout the Holocene epoch, we find a distinct anti-phasing of wind strength between the core and northern margin over multi-millennial timescales. During the early Holocene, the core westerlies were strong whereas the northern margin westerlies were weak. We observe the opposite pattern in the late Holocene. As this variation resembles modern seasonal variability, we suggest that our observed changes in westerly wind strength can best be explained by variations in sea surface temperature in the eastern South Pacific Ocean.Chile is ideally located to reconstruct past variability of the southern westerly wind belt (SWW) as the SWW almost entirely controls precipitation on the western side of the Andes in southern South America with an extreme north-south rainfall gradient from the semiarid, winter-rain climate in central Chile to yearround hyper-humid conditions in the fjord region of southern Chile 5 (Supplementary Fig. S1). Therefore, any paleoclimatic proxy record primarily controlled by rainfall changes is suitable for reconstructing past changes in the SWW in this region. In present-day austral winters, the SWW extends northward, providing rainfall to central Chile (33 • -40 • S), but zonal winds are reduced in its core zone in southernmost Chile (50 • -55 • S; Fig. 1a). During austral summer, the zonal wind pattern shows a latitudinally more confined and intensified SWW with maxima over southernmost Chile (Fig. 1b). Previous reconstructions of the SWW were primarily based on single sites and generally suggested a northward migration and intensification of the SWW during colder periods 1,2,4 . Intensity variations across the wind belt have only recently been addressed and interpreted in terms of co-varying

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“…Actualmente se cuenta con un número mayor de estaciones de registros en variadas localidades de la región y a la luz de estos antecedentes se puede concluir que las variaciones de la temperatura en Magallanes son muy similares, al menos desde los 52°S hacia el sur, debido a la alta correlación que muestra esta variable en su variación en relación a sus promedios diarios (Schneider et al 2003, Santana et al 2005. Esto último es muy importante ya que al establecerse algún tipo de tendencia térmica en Punta Arenas, ésta puede ser inferida también para otras localidades.…”

Section: Introductionunclassified

Variación De La Temperatura en Punta Arenas (Chile) en Los Últimos 120 Años

Santana

Butorovic

Olave

2009

Anales Instituto Patagonia (Chile)

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RESUMENSe presenta la serie de temperaturas de Punta Arenas correspondientes a 120 años, en un periodo que va desde 1888 hasta el 2007. Se analizan las variaciones que ha tenido este parámetro atmosférico a través de estos años, concluyéndose que han ocurrido periodos intercalados de alta y de bajas temperaturas en torno a su valor medio. Respecto a su tendencia y en referencia al valor promedio, es más bien estable, aunque si se considera una regresión lineal, ésta muestra un leve enfriamiento durante estos 120 años. Un análisis estacional de esta variable muestra algunos matices respecto al comportamiento anual. Se analizan por separado las series de medias de las máximas y de las mínimas mensuales y se hace su comparación con las medias por estación del año en cada uno de éstas. Finalmente se analizan los valores extremos mensuales que ha tenido la temperatura en la ciudad y se presentan los valores más frecuentes que éstas han tenido en este periodo, así como los valores récord alcanzados.Palabras clave: Punta Arenas, temperatura. ABSTRACTA sequence of temperature records from Punta Arenas for the 120 year period 1888 -2007 are presented. The analyses of how temperature has varied over the years has concluded that there have been periods when the temperature has been below and above the median. A linear regression performed on the data showed that the temperature has slightly cooled over the 120 years. From a seasonal analysis of temperature, there were variable intra-seasonal differences between years. Mean monthly means of maximum and minimum temperature are compared by station and year. The frequency, occurrence and extremes of monthly temperatures in Punta Arenas over the period are presented.

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Weather Observations Across the Southern Andes at 53°S

Cited by 167 publications

References 10 publications

A promising location in Patagonia for paleoclimate and paleoenvironmental reconstructions revealed by a shallow firn core from Monte San Valentín (Northern Patagonia Icefield, Chile)

A promising location in Patagonia for paleoclimate and paleoenvironmental reconstructions revealed by a shallow firn core from Monte San Valentín (Northern Patagonia Icefield, Chile)

Holocene changes in the position and intensity of the southern westerly wind belt

Variación De La Temperatura en Punta Arenas (Chile) en Los Últimos 120 Años

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