http://hdl.handle.net/20.500.12164/3079 2026-03-27T06:14:37Z 2026-03-27T06:14:37Z Davi, Nicole K. Pringle, Patrick Fiondella, Francesco Lockwood, Jeff Oelkers, Rose http://hdl.handle.net/20.500.12164/3081 2021-08-16T16:00:30Z 2021-05-21T00:00:00Z

Title: Online labs to introduce undergraduate students to scientific concepts and practices in tree-ring research Authors: Davi, Nicole K.; Pringle, Patrick; Fiondella, Francesco; Lockwood, Jeff; Oelkers, Rose Abstract: Scientists rely heavily on tree-ring records to better understand climate variability of the past millennium. Tree rings can also be utilized to give students a window into paleoclimate research, the methods scientists use, and the importance of scientific findings. Here, we present five online labs that introduce undergraduate students to the field of dendrochronology. Students learn about foundational tree-ring concepts and are guided to use many of the same tools and strategies as scientists, including exploring important field sites, measuring tree-ring data from those sites, using online paleoclimate databanks, and evaluating climate trends and extremes. The labs have been classroom tested and were modified based on a professional assessment, and faculty and student reviews. Faculty and student surveys and student lab grades show that the majority of students were able to meet the learning goals of the labs. Students reported that they felt they were working as scientists would, and, after completing the labs, that they better understood tree-ring science methods and applications. These materials were developed collaboratively with faculty input from a variety of institutions to have broad appeal and allow for use in a variety of classroom settings.

2021-05-21T00:00:00Z Davi, Nicole K. Rao, M. P. Wilson, R. Andreu-Hayles, L. Oelkers, Rose D'Arrigo, R. Nachin, B. Buckley, B. Pederson, N. Leland, C. Suran, B. http://hdl.handle.net/20.500.12164/3080 2021-08-16T16:00:28Z 2021-07-26T00:00:00Z

Title: Accelerated Recent Warming and Temperature Variability over the Past Eight Centuries in the Central Asian Altai from Blue Intensity in Tree Rings Authors: Davi, Nicole K.; Rao, M. P.; Wilson, R.; Andreu-Hayles, L.; Oelkers, Rose; D'Arrigo, R.; Nachin, B.; Buckley, B.; Pederson, N.; Leland, C.; Suran, B. Abstract: Warming in Central Asia has been accelerating over the past three decades and is expected to intensify through the end of this century. Here we develop a summer temperature reconstruction for western Mongolia spanning eight centuries (1269-2004 C.E.) using delta blue intensity measurements from annual rings of Siberian larch. A significant cooling response is observed in the year following major volcanic events and up to 5 years post-eruption. Observed summer temperatures since the 1990s are the warmest over the past eight centuries, an observation that is also well captured in CMIP5 climate model simulations. Projections for summer temperature relative to observations suggest further warming of between ∼3-6°C by the end of the century (2075-2099 cf. 1950-2004) under the RCP4.5 and RCP8.5 emission scenarios. We conclude that projected future warming lies beyond the range of natural climate variability for the past millennium as estimated by our reconstruction. Description: We have reconstructed nearly 750 years (1269-2004 C.E.) of summer temperatures in Mongolia based on Siberian Larch tree rings, using a relatively new analysis method called delta blue-light intensity (DBI). This is a region of the world with relatively few long records of climate, and one that is experiencing unprecedented warming over the last three decades. This warming is projected to intensify and reach levels that go beyond the range of natural climate variability that is estimated by our reconstruction. In our analysis, we capture the warming trends observed in instrumental records as well as extreme-cold events that coincide with the well-documented, large-scale volcanic events of 1459, 1601, 1810-1816, and 1885. Our results add to an increasing number of studies detailing the potential of DBI to improve paleoclimate models as compared to traditional tree-ring width analysis, especially in Siberian Larch and other species that express a significant heartwood/sapwood color change.

2021-07-26T00:00:00Z