High‐latitude forcing of regional aridification along the subtropical west coast of South America

Vuille, Mathias; Milana, Juan Pablo

doi:10.1029/2007gl031899

Cited by 32 publications

(30 citation statements)

References 16 publications

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“…A concurrent weakening of the SEPA may additionally facilitate frontal activity. In a more recent study, Vuille and Milana (2007) underlined the importance of blocking activity at high latitudes in the SE Pacific, independently of the ENSO, as a factor favouring the occurrence of rainfall in the southern fringe of the Atacama Desert.…”

Section: Precipitationmentioning

confidence: 99%

Climate change along the arid coast of northern Chile

Schulz

Boisier

Aceituno

2011

Intl Journal of Climatology

108

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Long-term precipitation records from the extremely arid northern coast of Chile (18°S-30°S) were analysed to assess changes occurring at different time scales. Results are presented here along with a discussion on changes in the temperature and cloudiness regimes in order to offer a more comprehensive overview of the climate evolution in this extremely arid region. Apart from a significant influence of ENSO on the rainfall regime, characterized by a tendency for more frequent rainfall events during El Niño episodes, changes at the decadal time scale were identified in association with the Interdecadal Pacific Oscillation (IPO). Thus, the warm IPO-phase is associated with increased precipitation, while the opposite occurs during the cold IPO-phase. Changes occurring at the interannual and decadal time scales are superimposed on a long-term precipitation decline during the 20th century. Apart from the intensified dryness, the temperature records show a positive long-term trend resulting mainly from an abrupt warming in the mid-1970s, principally associated with a marked upwards shift of the minimum daily temperature, coinciding with the change from the cold to the warm phase of the IPO. However, the period following this step-like warming has been characterized by a persistent cooling trend, most evident in the maximum daily temperature, which is coherent with a negative trend in the sea surface temperature over a large oceanic region off the coast of northern Chile. In the northernmost region, this behaviour in the temperature regime was accompanied by a strong decrease in cloudiness since the 1970s. The negative trend in rainfall and the decrease in the total cloud cover are certainly important factors that could explain the coastal vegetation decline over the past decades in the coastal region north of 24°S.

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Section: Precipitationmentioning

confidence: 99%

Climate change along the arid coast of northern Chile

Schulz

Boisier

Aceituno

2011

Intl Journal of Climatology

108

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“…(2003)(2004)(2005), the other numbers represent the number of stakes measured by CEAZA. for reduced precipitation are not yet clearly understood, but in addition to ENSO/PDO variations (Escobar and Aceituno, 1998), high-latitude forcing from the Amundsen Sea region may provide an additional explanation for the observed secular drying trend by modulating the location of the winter storm tracks (Vuille and Milana, 2007).…”

Section: Climatic Conditionsmentioning

confidence: 99%

“…Favier et al, 2009) and climatological (e.g. Masiokas et al, 2006;Vuille and Milana, 2007) studies carried out in this region highlight the lack of knowledge of glaciological processes at high elevation. The Pascua-Lama region (29 • 19 S, 70 • 01 W) is very close to the so-called "South America Arid Diagonal" (23-28 • S, Schwerdtfeger, 1970); north from this area glaciers are scarce until the intertropical zone.…”

Section: Introductionmentioning

confidence: 99%

“…The nearest monitoring sites to this subtropical region are Echaurren Glacier, Chile, 33 • 35 S (Escobar et al, 2000), Piloto Glacier, Argentina, 32 • 27 S (Leiva et al, 2007) to the south and Zongo and Chacaltaya glaciers ∼1500 km north in the Bolivian intertropical Andes, ∼16 • S (e.g. Wagnon et al, 1999;Francou et al, 2003). Climate conditions are considerably drier in the Pascua-Lama region than those observed 450 km south on Echaurren Glacier or on the Argentinian side of the Andean divide on Piloto Glacier (Falvey and Garreaud, 2007;Favier et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Glacier changes in the Pascua-Lama region, Chilean Andes (29° S): recent mass balance and 50 yr surface area variations

et al. 2011

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Abstract. Since 2003, a monitoring program has been conducted on several glaciers and glacierets in the Pascua-Lama region of the Chilean Andes (29 • S/70 • W; 5000 m a.s.l.), permitting the study of glaciological processes on ice bodies in a subtropical, arid, high-elevation area where no measurements were previously available. In this paper we present: (1) six years of glaciological surface mass balance measurements from four ice bodies in the area, including a discussion of the nature of the studied glaciers and glacierets and characterization of the importance of winter mass balance to annual mass balance variability; and (2) changes in surface area of twenty ice bodies in the region since 1955, reconstructed from aerial photographs and satellite images, which shows that the total glaciated surface area reduced by ∼29 % between 1955 and 2007, and that the rate of surface area shrinkage increased in the late 20th century. Based on these datasets we present a first interpretation of glacier changes in relation with climatic parameters at both local and regional scales.

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“…8). Despite the similarity of climate anomalies across the mid-latitudes of SSA forced by variations in AAO (Vuille and Milana 2007, Garreaud et al 2009, Quintana and Aceituno 2012, different mechanisms generated diverse and spatially-segregated responses of wildfire activity. In the moisture limited, biomass-poor ecosystems of the Mediterranean zone of central Chile, fire occurrence depends largely on preceding anomalous high precipitation that induces fine fuel build-up; it depends less on anomalous fuel desiccation during the springsummer season, which is consistently dry in the Mediterranean climate (Fig.…”

Section: Interannual Patterns Of Fire Activitymentioning

confidence: 99%

Ecological and climatic controls of modern wildfire activity patterns across southwestern South America

et al. 2012

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Abstract. Understanding how patterns of wildfire activity across biomes are shaped by heterogeneity in biomass resources to burn and atmospheric conditions conducive to burning is a high research priority in the context of global environmental change. Along a latitudinal gradient (25 to 568 S) from semi-arid scrublands through Mediterranean-type vegetation to wet forests in southwestern South America (SSA) we analyzed influences of mean climate and interannual climate variability on fire activity using documentary fire records from 1984 to 2008. We identified large regions with common temporal variability in annual area burned, related this variability to local interannual climate variability and in turn to modes of the major tropical and extratropical climate drivers of the southern hemisphere-El Niño-Southern Oscillation (ENSO) and the Antarctic Oscillation (AAO). Differences in fire activity response to interannual climate variability were related to the relative influences of available biomass to burn, and to weather effects on amounts of fine fuels and fuel moisture conditions. The pattern of average fire activity along this latitudinal moisture/productivity gradient corresponds well with the varying constraints model. This model predicts low fire activity towards the arid extreme due to reduced burnable biomass and again towards the humid extreme due to infrequent weather suitable for drying fuels, and predicts a broad zone of high fire activity at intermediate locations where resources to burn are abundant in all years and fuel moisture dries under reliably dry summer conditions. The dominant influence on interannual climate variability is AAO, which explained most of the variability in fire activity both by reducing seasonal precipitation in mesic and wet forests where fire is dependent on infrequent drought and by enhancing fine fuel production in Mediterranean-type vegetation where fuel amount and continuity constrain fire activity. In the context of the drying and warming trends in SSA related to the continued positive anomaly in AAO, our results underscore the importance of the varying constraints on fire activity and modulation of fire-climate relationships by different vegetation types, which is a much needed step toward developing fire projections under future climate.

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High‐latitude forcing of regional aridification along the subtropical west coast of South America

Cited by 32 publications

References 16 publications

Climate change along the arid coast of northern Chile

Climate change along the arid coast of northern Chile

Glacier changes in the Pascua-Lama region, Chilean Andes (29° S): recent mass balance and 50 yr surface area variations

Ecological and climatic controls of modern wildfire activity patterns across southwestern South America

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