Drought increase since the mid-20th century in the northern South American Altiplano revealed by a 389-year precipitation record
Drought increase since the mid-20th century in the northern South American Altiplano revealed by a 389-year precipitation record
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DOI：
10.5194/cp-19-457-2023
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发表时间：
2023-02
影响因子：
4.3
通讯作者：
M. Morales;Doris B. Crispin‐DelaCruz;C. Álvarez;D. Christie;M. E. Ferrero;L. Andreu‐Hayles;R. Villalba;Anthony Guerra;G. Ticse-Otarola;Ernesto C. Rodríguez-Ramírez;Rosmery LLocclla-Martínez;Joali Sanchez-Ferrer;Edilson Jimmy Requena-Rojas
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文献类型：
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作者：
M. Morales;Doris B. Crispin‐DelaCruz;C. Álvarez;D. Christie;M. E. Ferrero;L. Andreu‐Hayles;R. Villalba;Anthony Guerra;G. Ticse-Otarola;Ernesto C. Rodríguez-Ramírez;Rosmery LLocclla-Martínez;Joali Sanchez-Ferrer;Edilson Jimmy Requena-Rojas
抽象的。鉴于南美洲高原仪器降水记录的时间跨度较短，需要较长期的水文气候记录，以了解气候多变性的性质并提高降水的可预测性，而降水是高原和邻近干旱低地社会经济发展的关键自然资源。这一地区生长着塔拉帕卡纳多年生树种，这是一种对水文气候变化非常敏感的长寿树种，已被广泛用于高原中部和南部的年轮研究。然而，在秘鲁和智利高原北部(16-19∘S)，仍然存在基于树木年轮记录的高分辨率水文气候数据的缺口。我们的研究概述了南美高原北部1625-2013年春末-仲夏降水的时间演变，允许根据三个塔拉帕卡纳年表的区域重建来识别潮湿或干旱时期。在过去的4个世纪中，自1970年代以来，在高原北部，极端干旱事件的发生增加了，而重建的降水量则有减少的趋势。在我们389年的重建中，过去17年的平均降雨量是最干燥的。我们揭示了自20世纪70年代中期以来高原地区干旱状况的时间和空间同步性。基于树木年轮的独立水文气候重建和几个基于热带安第斯山脉其他可用替代指标的古气候记录记录了这种同步。通过我们的降水重建探测到了厄尔尼诺-南方涛动(ENSO)对北部高原降水的影响，这表明我们研究地区过去的干旱状况与ENSO暖事件有关。降雨重建的光谱特征显示了ENSO在十年、亚十年和年际时间尺度上的强烈变化，特别是在太平洋NI？O 3区。总体而言，与前几个世纪相比，最近降雨量减少，极端干旱事件增加，以及这项工作报告的降水与ENSO变化之间的耦合，在高原对水资源的需求日益增长的背景下，这是至关重要的信息。这项研究将有助于更好地了解该区域对21世纪与全球变暖有关的预计蒸散量增加的脆弱性和复原力。
Abstract. Given the short span of instrumental precipitation records in the South American Altiplano, longer-term hydroclimatic records are needed to understand the nature of climate variability and to improve the predictability of precipitation, a key natural resource for the socioeconomic development in the Altiplano and adjacent arid lowlands. In this region grows Polylepis tarapacana, a long-lived tree species that is very sensitive to hydroclimatic changes and has been widely used for tree-ring studies in the central and southern Altiplano. However, in the northern sector of the Peruvian and Chilean Altiplano (16–19∘ S) still exists a gap of high-resolution hydroclimatic data based on tree-ring records. Our study provides an overview of the temporal evolution of the late-spring–mid-summer precipitation for the period 1625–2013 CE at the northern South American Altiplano, allowing for the identification of wet or dry periods based on a regional reconstruction from three P. tarapacana chronologies. An increase in the occurrence of extreme dry events, together with a decreasing trend in the reconstructed precipitation, has been recorded since the 1970s in the northern Altiplano within the context of the last ∼4 centuries. The average precipitation over the last 17 years stands out as the driest in our 389-year reconstruction. We reveal a temporal and spatial synchrony across the Altiplano region of dry conditions since the mid-1970s. Independent tree-ring-based hydroclimate reconstructions and several paleoclimatic records based on other proxies available for the tropical Andes record this synchrony. The influence of El Niño–Southern Oscillation (ENSO) on the northern Altiplano precipitation was detected by our rainfall reconstruction that showed past drier conditions in our study region associated with ENSO warm events. The spectral properties of the rainfall reconstruction showed strong imprints of ENSO variability at decadal, sub-decadal, and inter-annual timescales, in particular from the Pacific NIÑO 3 sector. Overall, the recent reduction in precipitation in comparison with previous centuries, the increase in extreme dry events and the coupling between precipitation and ENSO variability reported by this work is essential information in the context of the growing demand for water resources in the Altiplano. This study will contribute to a better understanding of the vulnerability and resilience of the region to the projected evapotranspiration increase for the 21st century associated with global warming.