Collaborative Resesarch: P2C2--The Flavors of Southwest Hydroclimatic Extremes

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This project aims to investigate hydroclimatic variability in the American Southwest (SW) in a comprehensive manner by building on the long-established tree-ring record of SW drought as well as new pilot data. This will be accomplished by (a) integrating the use of both widely-used and newly emerging tree-ring, cave and lake proxies; (b) using an interannual- to-decadal-resolution focus on the last 2,000 years, and a coarser examination of the earlier Holocene and its apparent longer and more severe dry extremes; (c) deploying a broad mix of monitoring, calibration and cross-comparison of proxies; (d) specifically focusing on multiple temperature proxies, in addition to moisture sensitive proxies; (e) emphasizing seasonality, particularly the disentangling of cool-season and warm-season (monsoon) variability; and (f) integrating proxy records, climate modeling, and proxy forward modeling to increase understanding of regional climate feedbacks, causes of SW hydroclimatic variability, and model realism. The project aims to address six primary science questions: (1) How do moisture and temperature anomalies combine to produce the droughts and pluvials of the past? (2) How can a multiproxy approach best be used to investigate the various flavors of extreme hydroclimatic events over a range of time scales, interannual to centennial? (3) Are local temperature anomalies associated with hydroclimate extremes linked to large-scale temperatures, or are they more regional and related to hydroclimatic feedbacks? (4) What are the relative contributions of winter versus summer monsoon variations to SW megadrought and pluvial periods? (5) How well are hydroclimatic extremes and their drivers represented in state-of-the-art Earth System Models? (6) How can a refined understanding of drought and its drivers improve estimates of future drought risk?The broader impacts include supporting the training of graduate and undergraduate students; outreach to K-12 and general public education on climate variability via the Biosphere2 in Arizona; and stakeholder engagement with farmers, ranchers, public health, water managers, and urban managers with special emphasis on Colorado River water managers and users via regular outreach efforts of the multi-university Colorado River Research Group.