A5053897595- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Climate variability and models
- Tree-ring climate responses
- Pleistocene-Era Hominins and Archaeology
- Isotope Analysis in Ecology
- Archaeology and ancient environmental studies
- Geological formations and processes
- Climate change and permafrost
- Hydrology and Watershed Management Studies
- Marine and environmental studies
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Landslides and related hazards
- earthquake and tectonic studies
- Geological Studies and Exploration
- Atmospheric and Environmental Gas Dynamics
- Coastal wetland ecosystem dynamics
- Meteorological Phenomena and Simulations
- Hydrocarbon exploration and reservoir analysis
- Evolution and Paleontology Studies
- Oceanographic and Atmospheric Processes
- Astro and Planetary Science
- Arctic and Antarctic ice dynamics
- Geomagnetism and Paleomagnetism Studies
NOAA National Centers for Environmental Information
2012-2024
Cooperative Institute for Research in Environmental Sciences
2011-2021
University of Colorado Boulder
2008-2021
National Oceanic and Atmospheric Administration
2011-2017
SUNY Oneonta
2015
University of Colorado System
2010-2014
NSF National Center for Atmospheric Research
2003-2006
University of Arizona
2000-2006
University of California, Santa Cruz
1998-2002
Arizona Geological Survey
2000
Deciphering the evolution of global climate from end Last Glacial Maximum approximately 19 ka to early Holocene 11 presents an outstanding opportunity for understanding transient response Earth's system external and internal forcings. During this interval warming, decay ice sheets caused mean sea level rise by 80 m; terrestrial marine ecosystems experienced large disturbances range shifts; perturbations carbon cycle resulted in a net release greenhouse gases CO(2) CH(4) atmosphere; changes...
We have compiled 36 previously published palaeoclimate records to determine the timing and spatial pattern of century-scale abrupt changes in Asian monsoon precipitation since last deglaciation. identify events from (1) interpretations authors these (2) more objective moving t-test calculation. Our results indicate that climatic occurred at ~11.5 cal. ka, 4.5–5.0 ka ad 1300. At start Holocene (~11.5 ka), increased dramatically. This change is synchronous with an warming North Atlantic....
A comprehensive database of paleoclimate records is needed to place recent warming into the longer-term context natural climate variability. We present a global compilation quality-controlled, published, temperature-sensitive proxy extending back 12,000 years through Holocene. Data were compiled from 679 sites where time series cover at least 4000 years, are resolved sub-millennial scale (median spacing 400 or finer) and have one age control point every 3000 with cut-off values slackened in...
Abstract We present a record of monsoon variations for the early and middle Holocene that is inferred from geochemistry sediment cores Ahung Co, lake in central Tibet. The resolution this better than 50 yr age model derived radiocarbon ages terrestrial charcoal, which eliminates errors associated with hard-water effect. made down-core geochemical measurements % carbonate, organic carbon, C/N δ 13 C bulk matter, 18 O dolomite. Proxy calibration modern water-balance reconstruction show these...
Paleoclimate records of effective moisture (precipitation minus evaporation, or P–E) show a dry (low moisture) period in mid-latitude arid/semi-arid central Asia during the early Holocene (11,000–8,000 years ago) relative to middle and late Holocene, contrast evidence for greater-than-present precipitation at same time south east Asian monsoonal areas. To investigate spatial differences climate response over we conducted series simulations with Community Climate System Model version 3...
A new temperature record from East Africa demonstrates that the tropical lapse rate steepened during last ice age.
Abstract. The Paleoclimate Modelling Intercomparison Project (PMIP3) now includes the 8.2 ka event as a test of model sensitivity to North Atlantic freshwater forcing. To provide benchmarks for intercomparison, we compiled and analyzed high-resolution records spanning this event. Two previously-described anomaly patterns that emerge are cooling around drier conditions in Northern Hemisphere tropics. Newer compilation more robustly-defined wetter Southern tropics regionally-limited warming...
Marking its 50th year in 2024, the International Tree-Ring Databank (ITRDB) is a lasting and invaluable scientific resource, composed of over 6000 tree-ring chronology sites more than 9000 publicly available measurement data files. It central global repository for chronologies associated measurements, providing foundation centennial to millennial length climate reconstructions, including large-scale spatially gridded datasets hundreds studies on earth systems, ecological processes, societal...
Documenting the spatial extent of 8.2 ka event is essential for understanding possible response climate system to a freshwater perturbation in North Atlantic. In this research, we analyzed paleoclimate proxy records from 52 sites using statistical test detect anomalies associated with event. Our results show that occurred many parts Northern Hemisphere extratropics and tropics. Evidence tropics more spotty, but detection rates are similar extratropics, suggesting tropical evidence will...
A well-dated pollen record from a large lake located on the meadow–steppe ecotone provides history of shift in response to monsoonal climate changes over last 6000 years central Tibetan Plateau. The indicates that shifted eastward during 6000–4900, 4400–3900, and 2800–1600 cal. yr BP when steppes occupied this region, whereas it westward other intervals were replaced by meadows. quantitative reconstruction paleoclimate derived shows monsoon precipitation fluctuated around present level Three...
Abstract Responses of the thermohaline circulation (THC) to freshwater forcing (hosing) in subpolar North Atlantic Ocean under present-day and last glacial maximum (LGM) conditions are investigated using National Center for Atmospheric Research Community Climate System Model versions 2 3. Three sets simulations analyzed, with each set including a control run hosing run. The first two an open closed Bering Strait. third one is LGM conditions, which has Results show that THC nearly collapses...
Abstract Reconstructions of temperature and hydrology from lake sedimentary archives have made fundamental contributions to our understanding past, present, future climate help evaluate general circulation models (GCMs). However, because paleoclimate observations are an indirect (proxy) constraint on climatic variables, confounding effects proxy processes complicate interpretations these archives. To circumvent uncertainties inherent data‐model comparison, system (PSMs) provide transfer...
Paleo proxy data and previous modeling studies both indicate that the massive discharge of icebergs into North Atlantic may have led to a (nearly) collapsed meridional overturning circulation (AMOC), resulting in seesaw‐like climate change between Pacific Atlantic, with warming former cooling latter. Here by using fully coupled model, we show this Pacific‐Atlantic seesaw associated changes AMOC can only occur when Bering Strait is closed. As strait closed, oceanic communication cut off. When...
Abstract. We compared four simulations of the 8.2 ka event to assess climate model sensitivity and skill in responding North Atlantic freshwater perturbations. All used same forcing, 2.5 Sv for one year, applied either Hudson Bay (northeastern Canada) or Labrador Sea (between Canada's coast Greenland). This pulse induced a decadal-mean slowdown 10–25% Meridional Overturning Circulation (AMOC) models caused large-scale pattern anomalies that matched proxy evidence cooling Northern Hemisphere...
Abstract Paleoscience data are extremely heterogeneous; hundreds of different types measurements and reconstructions routinely made by scientists on a variety physical samples. This heterogeneity is one the biggest barriers to finding paleoclimatic records, building large‐scale products, use paleoscience beyond community specialists. Here, we document Paleoenvironmental Standard Terms (PaST) thesaurus, first authoritative vocabulary standardized variable names for paleoenvironmental...