A5004691211- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Oceanographic and Atmospheric Processes
- Climate variability and models
- Groundwater and Isotope Geochemistry
- Pacific and Southeast Asian Studies
- Geological formations and processes
- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Remote Sensing and Land Use
- Landslides and related hazards
- Geological and Geophysical Studies
- Coral and Marine Ecosystems Studies
- Geophysics and Gravity Measurements
- Aeolian processes and effects
- Tree-ring climate responses
- Geological and Geochemical Analysis
- Climate change and permafrost
- Rangeland and Wildlife Management
- Marine and environmental studies
- Archaeology and ancient environmental studies
- Coastal wetland ecosystem dynamics
- Environmental DNA in Biodiversity Studies
- Pleistocene-Era Hominins and Archaeology
University of Illinois Urbana-Champaign
2016-2025
University of Arizona
2008-2013
Georgia Institute of Technology
2012-2013
University of New Brunswick
2009
Dunedin Public Hospital
1972
Atmospheric deep convection in the west Pacific plays a key role global heat and moisture budgets, yet its response to orbital abrupt climate change events is poorly resolved. Here, we present four absolutely dated, overlapping stalagmite oxygen isotopic records from northern Borneo that span most of last glacial cycle. The suggest Borneo's hydroclimate shifted phase with precessional forcing but was only weakly affected by glacial-interglacial changes boundary conditions. Regional likely...
The El Niño–Southern Oscillation (ENSO) represents the largest source of year-to-year global climate variability. While Earth system models suggest a range possible shifts in ENSO properties under continued greenhouse gas forcing, many centuries preindustrial data are required to detect potential shift recent extremes. Here we reconstruct strength variations over last 7,000 years with new ensemble fossil coral oxygen isotope records from Line Islands, located central equatorial Pacific....
Abstract In September 2016, the annual meeting of International Union for Quaternary Research’s Loess and Pedostratigraphy Focus Group, traditionally referred to as a LoessFest, met in Eau Claire, Wisconsin, USA. The 2016 LoessFest focused on “thin” loess deposits transportation surfaces. This included 75 registered participants from 10 countries. Almost half were outside United States, 18 students. review is introduction special issue Research that originated presentations discussions at...
Abstract. Reconstructions of global hydroclimate during the Common Era (CE; past ∼2000 years) are important for providing context current and future environmental change. Stable isotope ratios in water quantitative indicators on regional to scales, these signals encoded a wide range natural geologic archives. Here we present Iso2k database, compilation previously published datasets from variety archives that record stable oxygen (δ18O) or hydrogen (δ2H) isotopic compositions waters, which...
Abstract The hydrologic cycle is a fundamental component of the climate system with critical societal and ecological relevance. Yet gaps persist in our understanding water fluxes their response to increased greenhouse gas forcing. stable isotope ratios oxygen hydrogen provide unique opportunity evaluate hydrological processes investigate role variability its sensitivity change. Water isotopes also form basis many paleoclimate proxies variety archives, including ice cores, lake marine...
Abstract The spatial domain of the Asian monsoon has been defined by intensity, seasonal concentration, and annual range precipitation. Monsoon subdomains, such as Indian monsoon, East western North Pacific have also identified based on wind reversals well timing source moisture. However, precipitation across region is heterogeneous spatially complex may influences farther north than commonly assumed, particularly if scientists consider records past variability spanning current interglacial...
Abstract Understanding controls on the stable isotopic composition of precipitation and vapor in West Pacific Warm Pool is vital for accurate representation convective processes models correct interpretation isotope‐based paleoclimate proxies, yet a lack direct observational evidence precludes utility these tracers. Results from measurement campaign at Manus Island, Papua New Guinea 28 April to 8 May 2013 demonstrate variability (δD δ 18 O) individual events over 10 day period. Isotope...
The relationship between salinity and the stable oxygen isotope ratio of seawater (δ18Osw) is utmost importance to quantitative reconstruction past changes in from δ18O values marine carbonates. This often considered be uniform across water masses, but constancy δ18Osw-salinity space time remains uncertain, as δ18Osw responds varying atmospheric vapor sources pathways, while does not. Here we present new data sites spanning tropical Pacific Ocean. New Palau, Papua Guinea, Kiritimati,...
Abstract Probing the dynamics of Earth's hydrologic cycle benefits from use isotope‐equipped global climate models. However, isotope model simulations are not often compared together, along with existing observations, to assess distribution simulated stable variability. Here we evaluate spatial and temporal patterns tropical Pacific precipitation variability in models second Stable Water Isotope Intercomparison Group experiment observations. The is home many isotope‐based proxies...
A high‐resolution (2–9 year sampling interval) fossil pollen record from the Galápagos Islands, which spans last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Niño Southern Oscillation variability provided evidence shifts in relative abundance individual species rather than immigration or extinction. Droughts Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to previous...
Abstract Tropical Pacific seawater and precipitation stable oxygen isotope data aid in understanding modern oceanic atmospheric interactions, these are particularly valuable as they archived isotope‐based paleoclimate records. However, the absence of time series limits ability to identify influences on data, precluding robust interpretations. We present a new 10 year sub‐monthly record values (δ 18 O sw δ p ) from Koror, Palau. Our dataset indicates that temporally, is strongly influenced by...
Abstract Terrestrial proxies of wind direction spanning the last deglaciation suggest easterly winds were present near Laurentide Ice Sheet margin in North American midcontinent. However, existence and spatial extent such have not been investigated with transient paleoclimate model simulations, which could provide improved dynamical context for interpreting causes these winds. Here we assess near-surface retreating southern using iTRACE, a simulation deglacial climate from 20–11 ka. Near...
Potential anthropogenic shifts in the hydroclimate impacts of El Niño Southern Oscillation (ENSO) extremes are poorly resolved by available data. Water isotopologues provide valuable tracers hydroclimatic processes, including balance precipitation versus evaporation and relative importance regional local drivers variability  (Dee et al., 2023 references therein; Moerman 2013). However, very few water isotopologue datasets exist tropical Pacific, those that do fail to...
Abstract Stable oxygen isotopic ratios in corals (δ 18 O coral ) are commonly utilized to reconstruct climate variability beyond the limit of instrumental observations. These measurements provide constraints on past seawater temperature, due thermodynamics fractionation, but also salinity, as both salinity and δ sw similarly affected by precipitation/evaporation, advection, other processes. We use historical observations, isotope‐enabled model simulations, PAGES Iso2k database assess...
Abstract Finely laminated sediments within Bainbridge Crater Lake, Galápagos, provide a record of El Niño–Southern Oscillation (ENSO) events over the Holocene. Despite importance this sediment record, hypotheses for how climate variability is preserved in lake have not been tested. Here we present results long‐term monitoring local and limnology revised interpretation record. Brown‐green, organic‐rich, siliciclastic laminae reflect warm, wet conditions typical Niño events, whereas carbonate...
Abstract Reconstructing past changes in the spatial structure of tropical Pacific hydroclimate requires archives moisture balance across gradients precipitation. To date, only one, 600‐year, terrestrial record is available for central (CTP) from Washington Lake, Island, limiting ability to test hypotheses regarding location CTP Intertropical Convergence Zone (ITCZ) last millennium. A new lake sediment Lake 30, Kiritimati, Republic Kiribati, 3° south provides additional constraints on ITCZ...
Oceanic islands support unique biotas but often lack ecological redundancy, so that the removal of a species can have large effect on ecosystem. The larger Galápagos Archipelago once had one or two giant tortoise were dominant herbivore. Using paleoecological techniques, we investigate cascade highland ecosystems resulted from whalers removing many thousands tortoises lowlands. We hypothesize seasonal migration now-extinct to highlands was curtailed by decreased intraspecific competition....