Given the short span of instrumental precipitation records in the South American Altiplano, long-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 socio-economic 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 (16º–19º S) still exist a gap of hydroclimatic tree-ring records. Our study provides an overview of the temporal evolution of annual 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 composed by three P. tarapacana chronologies. An increase in the occurrence rate of extreme dry events, together with a decreasing trend in the reconstructed precipitation, have been recorded since the 1970s decade in the northern Altiplano within the context of the last ~four centuries. The average precipitation of the last 17-year stands out as the driest in our 389-years reconstruction. We revealed a temporal and spatial synchrony across the Altiplano region of wet conditions during the first half of the 19th century and the drought conditions since mid 1970s recorded by independent tree-ring based hydroclimate reconstructions and several paleoclimatic records based on other proxies available for the tropical Andes. The rainfall reconstruction also provides valuable information about the ENSO influences in the northern Altiplano precipitation. The spectral properties of the rainfall reconstruction showed strong imprints of ENSO variability at decadal, sub-decadal and inter-annual time-scale, in particular from the Pacific N3 sector. Overall, the remarkable 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 that will contribute to a better understanding of the vulnerability/resilience of the region to the projected evapotranspiration increase for the 21st century associated with global warming.

Given the short span of instrumental precipitation records in the South American Altiplano, long-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 socio-economic 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 have been widely used for tree-ring studies in the central and southern Altiplano. However, in the northern sector of the Peruvian and Chilean Altiplano (16º–19º S) still exist a gap of hydroclimatic tree-ring records. Our study provides an overview of the temporal evolution of annual 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 composed by three P. tarapacana chronologies. An increase in the occurrence rate of extreme dry events, together with a decreasing trend in the reconstructed precipitation, have been recorded since the 1970s decade in the northern Altiplano within the context of the last ~four centuries. The average precipitation of the last 17-year stands out as the driest in our 389-years reconstruction. We revealed a temporal and spatial synchrony across the Altiplano region of wet conditions during the first half of the 19th century and the drought conditions since mid 1970s recorded by independent tree-ring based hydroclimate reconstructions and several paleoclimatic records based on other proxies available for the tropical Andes. The rainfall reconstruction provides also valuable information about the ENSO influences in the northern Altiplano precipitation. The spectral properties of the rainfall reconstruction showed strong imprints of ENSO variability at decadal, sub-decadal and inter-annual time-scale, in particular from the Pacific N3 sector. Overall, the remarkable 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 that will contribute to a better understanding of the vulnerability/resilience of the region to the projected evapotranspiration increase for the 21st century associated to global warming.

Given the short span of instrumental precipitation records in the South American Altiplano, long-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 socio-economic 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 have been widely used for tree-ring studies in the central and southern Altiplano. However, in the northern sector of the Peruvian and Chilean Altiplano (16º–19º S) still exist a gap of hydroclimatic tree-ring records. Our study provides an overview of the temporal evolution of annual 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 composed by three P. tarapacana chronologies. An increase in the occurrence rate of extreme dry events, together with a decreasing trend in the reconstructed precipitation, have been recorded since the 1970s decade in the northern Altiplano within the context of the last ~four centuries. The average precipitation of the last 17-year stands out as the driest in our 389-years reconstruction. We revealed a temporal and spatial synchrony across the Altiplano region of wet conditions during the first half of the 19th century and the drought conditions since mid 1970s recorded by independent tree-ring based hydroclimate reconstructions and several paleoclimatic records based on other proxies available for the tropical Andes. The rainfall reconstruction provides also valuable information about the ENSO influences in the northern Altiplano precipitation. The spectral properties of the rainfall reconstruction showed strong imprints of ENSO variability at decadal, sub-decadal and inter-annual time-scale, in particular from the Pacific N3 sector. Overall, the remarkable 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 that will contribute to a better understanding of the vulnerability/resilience of the region to the projected evapotranspiration increase for the 21st century associated to global warming.

بالنظر إلى الفترة القصيرة لسجلات هطول الأمطار الفعالة في ألتيبلانو أمريكا الجنوبية، هناك حاجة إلى سجلات مناخية مائية طويلة الأجل لفهم طبيعة تقلب المناخ وتحسين القدرة على التنبؤ بهطول الأمطار، وهو مورد طبيعي رئيسي للتنمية الاجتماعية والاقتصادية في ألتيبلانو والأراضي المنخفضة القاحلة المجاورة. في هذه المنطقة ينمو Polylepis tarapacana، وهو نوع شجرة طويل العمر حساس للغاية للتغيرات المناخية المائية وقد استخدم على نطاق واسع لدراسات حلقات الأشجار في وسط وجنوب ألتيبلانو. ومع ذلك، في القطاع الشمالي من بيرو وتشيلي ألتيبلانو (16-19 درجة جنوبا) لا تزال هناك فجوة في سجلات حلقات الأشجار المائية المناخية. تقدم دراستنا لمحة عامة عن التطور الزمني لهطول الأمطار السنوي للفترة 1625-2013 م في ألتيبلانو شمال أمريكا الجنوبية، مما يسمح بتحديد الفترات الرطبة أو الجافة على أساس إعادة الإعمار الإقليمية التي تتألف من ثلاثة التسلسل الزمني P. tarapacana. تم تسجيل زيادة في معدل حدوث الأحداث الجافة الشديدة، إلى جانب اتجاه تنازلي في هطول الأمطار المعاد بناؤه، منذ عقد السبعينيات في شمال ألتيبلانو في سياق القرون الأربعة الماضية. يبرز متوسط هطول الأمطار خلال الـ 17 عامًا الماضية باعتباره الأكثر جفافًا في إعادة الإعمار التي استمرت 389 عامًا. كشفنا عن تزامن زمني ومكاني عبر منطقة ألتيبلانو للظروف الرطبة خلال النصف الأول من القرن التاسع عشر وظروف الجفاف منذ منتصف السبعينيات المسجلة من خلال إعادة بناء المناخ المائي المستقل القائم على حلقات الأشجار والعديد من السجلات المناخية القديمة بناءً على وكلاء آخرين متاحين لجبال الأنديز الاستوائية. كما توفر إعادة بناء هطول الأمطار معلومات قيمة حول تأثيرات النينيو في هطول الأمطار في شمال ألتيبلانو. أظهرت الخصائص الطيفية لإعادة بناء هطول الأمطار بصمات قوية على تقلب التقلبات الجنوبية لظاهرة النينيو في النطاق الزمني العشري ودون العشري وبين السنوات، لا سيما من قطاع المحيط الهادئ N3. بشكل عام، يعد الانخفاض الأخير الملحوظ في هطول الأمطار مقارنة بالقرون السابقة، والزيادة في الأحداث الجافة الشديدة والاقتران بين هطول الأمطار وتقلب النينيو الذي أبلغ عنه هذا العمل معلومات أساسية في سياق الطلب المتزايد على الموارد المائية في ألتيبلانو والتي ستساهم في فهم أفضل لضعف/مرونة المنطقة لزيادة التبخر والنتح المتوقعة للقرن الحادي والعشرين المرتبطة بالاحترار العالمي.