@article{KhiderEmileGeayMcKayetal.2019, author = {Khider, D. and Emile-Geay, J. and McKay, N. P. and Gil, Y. and Garijo, D. and Ratnakar, V and Alonso-Garcia, M. and Bertrand, S. and Bothe, O. and Brewer, P. and Bunn, A. and Chevalier, M. and Comas-Bru, L. and Csank, A. and Dassie, E. and DeLong, K. and Felis, T. and Francus, P. and Frappier, A. and Gray, W. and Goring, S. and Jonkers, L. and Kahle, M. and Kaufman, D. and Kehrwald, N. M. and Martrat, B. and McGregor, H. and Richey, J. and Schmittner, A. and Scroxton, N. and Sutherland, E. and Thirumalai, Kaustubh and Allen, K. and Arnaud, F. and Axford, Y. and Barrows, T. and Bazin, L. and Birch, S. E. Pilaar and Bradley, E. and Bregy, J. and Capron, E. and Cartapanis, O. and Chiang, H-W and Cobb, K. M. and Debret, M. and Dommain, R{\´e}ne and Du, J. and Dyez, K. and Emerick, S. and Erb, M. P. and Falster, G. and Finsinger, W. and Fortier, D. and Gauthier, Nicolas and George, S. and Grimm, E. and Hertzberg, J. and Hibbert, F. and Hillman, A. and Hobbs, W. and Huber, M. and Hughes, A. L. C. and Jaccard, S. and Ruan, J. and Kienast, M. and Konecky, B. and Le Roux, G. and Lyubchich, V and Novello, V. F. and Olaka, L. and Partin, J. W. and Pearce, C. and Phipps, S. J. and Pignol, C. and Piotrowska, N. and Poli, M-S and Prokopenko, A. and Schwanck, F. and Stepanek, C. and Swann, G. E. A. and Telford, R. and Thomas, E. and Thomas, Z. and Truebe, S. and von Gunten, L. and Waite, A. and Weitzel, N. and Wilhelm, B. and Williams, J. and Winstrup, M. and Zhao, N. and Zhou, Y.}, title = {PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data}, series = {Paleoceanography and paleoclimatology}, volume = {34}, journal = {Paleoceanography and paleoclimatology}, number = {10}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2572-4517}, doi = {10.1029/2019PA003632}, pages = {1570 -- 1596}, year = {2019}, abstract = {The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches.}, language = {en} } @article{BrunelleSigmanJaccardetal.2010, author = {Brunelle, Brigitte G. and Sigman, Daniel M. and Jaccard, Samuel Laurent and Keigwin, Lloyd D. and Plessen, Birgit and Schettler, Georg and Cook, Mea S. and Haug, Gerald H.}, title = {Glacial/interglacial changes in nutrient supply and stratification in the western subarctic North Pacific since the penultimate glacial maximum}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2010.03.010}, year = {2010}, abstract = {In piston cores from the open subarctic Pacific and the Okhotsk Sea, diatom-bound delta N-15 (delta N-15(db)), biogenic opal, calcium carbonate, and barium were measured from coretop to the previous glacial maximum (MIS 6). Glacial intervals are generally characterized by high delta N-15(db) (similar to 8 parts per thousand) and low productivity, whereas interglacial intervals have a lower delta N-15(db) (5.7-6.3 parts per thousand) and indicate high biogenic productivity. These data extend the regional swath of evidence for nearly complete surface nutrient utilization during glacial maxima, consistent with stronger upper water column stratification throughout the subarctic region during colder intervals. An early deglacial decline in delta N-15(db) of 2 parts per thousand at similar to 17.5 ka, previously observed in the Bering Sea, is found here in the open subarctic Pacific record and arguably also in the Okhotsk, and a case can be made that a similar decrease in delta N-15(db) occurred in both regions at the previous deglaciation as well. The early deglacial delta N-15(db) decrease, best explained by a decrease in surface nutrient utilization, appears synchronous with southern hemisphere-associated deglacial changes and with the Heinrich 1 event in the North Atlantic. This delta N-15(db) decrease may signal the initial deglacial weakening in subarctic North Pacific stratification and/or a deglacial increase in shallow subsurface nitrate concentration. If the former, it would be the North Pacific analogue to the increase in vertical exchange inferred for the Southern Ocean at the time of Heinrich Event 1. In either case, the lack of any clear change in paleoproductivity proxies during this interval would seem to require an early deglacial decrease in the iron-to-nitrate ratio of subsurface nutrient supply or the predominance of light limitation of phytoplankton growth during the deglaciation prior to Bolling-Allerod warming.}, language = {en} } @article{StuderMartinezGarciaJaccardetal.2012, author = {Studer, Anja S. and Martinez-Garcia, Alfredo and Jaccard, Samuel L. and Girault, France E. and Sigman, Daniel M. and Haug, Gerald H.}, title = {Enhanced stratification and seasonality in the Subarctic Pacific upon Northern Hemisphere Glaciation-New evidence from diatom-bound nitrogen isotopes, alkenones and archaeal tetraethers}, series = {Earth \& planetary science letters}, volume = {351}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2012.07.029}, pages = {84 -- 94}, year = {2012}, abstract = {Coincident with the intensification of Northern Hemisphere Glaciation (WIG) around 2.73 million years (Ma) ago, sediment cores from both the open subarctic North Pacific and the Antarctic indicate a rapid decline in diatom opal accumulation flux to the seabed, representing one of the most abrupt and dramatic changes in the marine sediment record associated with the development of Pleistocene glacial cycles. In the North Pacific, bulk sediment nitrogen isotope data and alkenone-derived sea surface temperature (SST) estimates suggest that the productivity decline was driven by reduced exchange between surface and deep water, due to weaker wind-driven upwelling and/or a strengthening of the halocline (i.e. "stratification"). In this study of the 2.73 Ma transition at Ocean Drilling Program (ODP) Site 882 in the western subarctic North Pacific, diatom-bound nitrogen isotopes (delta N-15(db)), alkenone mass accumulation rate, and alkenone- and archaeal tetraether-based SST reconstructions support the stratification hypothesis, indicating perennially lower export production, generally higher nitrate consumption, and greater inter-seasonal variation in SST after the 2.73 Ma transition. In addition, the delta N-15(db) of large and small size fractions of Coscinodiscus spp. suggest that these diatoms grew mostly during the spring bloom during the late Pliocene, switching to their current fall-to-winter growth period at the 2.73 Ma transition; this view is consistent with their decline in dominance and provides further evidence for increased stratification (reduced vertical exchange) in the North Pacific after 2.73 Ma. The delta N-15(db) data indicate that, over the similar to 100 kyr period after the 2.73 Ma transition studied here, nitrate consumption did not reach late Pleistocene ice age levels and that nitrate consumption in post-2.73 Ma warm stages was similar to that before the transition, even though productivity was greatly reduced. We tentatively attribute this to relatively weak dust-borne iron inputs in the early post-2.73 Ma period.}, language = {en} } @misc{SernoWincklerAndersonetal.2017, author = {Serno, Sascha and Winckler, Gisela and Anderson, Robert F. and Jaccard, Samuel L. and Kienast, Stephanie S. and Haug, Gerald H.}, title = {Change in dust seasonality as the primary driver for orbital-scale dust storm variability in East Asia}, series = {Geophysical research letters}, volume = {44}, journal = {Geophysical research letters}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1002/2016GL072345}, pages = {3796 -- 3805}, year = {2017}, abstract = {Glacial periods are recognized to be dustier than interglacials, but the conditions leading to greater dust mobilization are poorly defined. Here we present a new high-resolution dust record based on Th-230-normalized He-4 flux from Ocean Drilling Program site 882 in the Subarctic North Pacific covering the last 170,000years. By analogy with modern relationships, we infer the mechanisms controlling orbital-scale dust storm variability in East Asia. We propose that orbital-scale dust flux variability is the result of an expansion of the dust season into summer, in addition to more intense dust storms during spring and fall. The primary drivers influencing dust flux include summer insolation at subarctic latitudes and variable Siberian alpine glaciation, which together control the cold air reservoir in Siberia. Changes in the extent of the Northern Hemisphere ice sheets may be a secondary control.}, language = {en} }