A5026275233- Geology and Paleoclimatology Research
- Climate variability and models
- Tree-ring climate responses
- Groundwater and Isotope Geochemistry
- Isotope Analysis in Ecology
- Hydrology and Watershed Management Studies
- Tropical and Extratropical Cyclones Research
- Methane Hydrates and Related Phenomena
- Pleistocene-Era Hominins and Archaeology
- Atmospheric and Environmental Gas Dynamics
- Oceanographic and Atmospheric Processes
- Hydrocarbon exploration and reservoir analysis
- Geological formations and processes
- Geological and Geophysical Studies
- Cryospheric studies and observations
- Meteorological Phenomena and Simulations
- Climate change and permafrost
- Flood Risk Assessment and Management
- Geophysics and Gravity Measurements
- Coral and Marine Ecosystems Studies
- Pacific and Southeast Asian Studies
- Hydrology and Sediment Transport Processes
- Karst Systems and Hydrogeology
- Coastal wetland ecosystem dynamics
- Climate Change and Health Impacts
Rice University
2018-2024
Brown University
2015-2019
The University of Texas at Austin
2018-2019
University of Texas Institute for Geophysics
2018
University of Southern California
2013-2015
Southern California University for Professional Studies
2014-2015
Southern California Earthquake Center
2014-2015
Abstract Paleoclimate observations constitute the only constraint on climate behavior prior to instrumental era. However, such provide indirect (proxy) constraints physical variables. Proxy system models aim improve interpretation of and better quantify their inherent uncertainties. existing are currently scattered in literature, making integration difficult. Here, we present a comprehensive modeling framework for proxy systems, named PRYSM . For this initial iteration, focus water‐isotope...
The El Niño-Southern Oscillation (ENSO) shapes global climate patterns yet its sensitivity to external forcing remains uncertain. Modeling studies suggest that ENSO is sensitive sulfate aerosol associated with explosive volcanism but observational support for this effect ambiguous. Here, we used absolutely dated fossil corals from the central tropical Pacific gauge ENSO's response large volcanic eruptions of last millennium. Superposed epoch analysis reveals a weak tendency an Niño-like in...
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 Paleoclimate data assimilation has recently emerged as a promising technique to estimate past climate states. Here we test two of the underlying assumptions paleoclimate applied so far: (1) proxies can be modeled linear, univariate recorders temperature and (2) structural errors in GCMs neglected. To investigate these points related uncertainties, perform series synthetic, assimilation‐based reconstructions where “pseudo” are generated with physically based proxy system models...
Abstract. Paleoclimatic records provide valuable information about Holocene climate, revealing aspects of climate variability for a multitude sites around the world. However, such data also possess limitations. Proxy networks are spatially uneven, seasonally biased, uncertain in time, and present variety challenges when used concert to illustrate complex variations past climate. assimilation provides one approach reconstructing that can account diverse nature proxy while maintaining...
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...
Mississippi River floods rank among the costliest climate-related disasters in world. Improving flood predictability, preparedness, and response at seasonal to decadal time-scales requires an understanding of climatic controls that govern occurrence. Linking occurrence persistent modes climate variability like El Niño-Southern Oscillation (ENSO) has proven challenging, due part limited number high-magnitude available for study instrumental record. To augment relatively short record, we use...
Abstract The oxygen and hydrogen isotopic composition in snow ice have long been utilized to reconstruct past temperatures of polar regions, under the assumption that post‐depositional processes such as sublimation do not fractionate snow. In low‐accumulation (<0.01 m yr −1 ) areas near McMurdo Dry Valleys Antarctica, surface samples exceptionally low deuterium excess values (d‐excess ≡ δD – 8*δ 18 O)—sometimes negative −5‰—an uncommon phenomenon is fully understood. Here we use both an...
Abstract Water isotope data from ice cores, particularly δ 18 O, have long been used in paleoclimatology. Although O has primarily interpreted as a proxy for local air temperature, isotope‐enabled climate models established that there are many nonlocal and nontemperature‐related climatic influences on isotopic signals at coring locations. Moreover, recent observational studies linked core isotopes to patterns of variability, midlatitude atmospheric circulation variations tropical climate....
Significance Climate models are foundational to formulations of climate policy and must successfully reproduce key features the system. The temporal spectrum observed global surface temperature is one such critical benchmark. This known obey scaling laws connecting astronomical forcings, from orbital annual scales. We provide evidence that current hierarchy capable reproducing increase in variance global-mean at low frequencies. suggest successful predictions decadal-to-centennial horizons...
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...
Abstract The interpretation of variations in the global isotopic composition precipitation and water vapor can be strengthened using an isotope‐enabled atmospheric general circulation model (AGCM). Here we present a fast‐physics suitable for long ensemble integrations: efficient AGCM Simplified Parameterizations, Primitive Equation Dynamics (SPEEDY), with newly added isotope physics. (SPEEDY‐isotope‐enabled reconstructions (IER)) simulates hydrological cycle ratios at fraction computational...
Uncertainty surrounding the future response of El Niño-Southern Oscillation (ENSO) variability to anthropogenic warming necessitates study past ENSO sensitivity substantial climate forcings over geological history. Here, we focus on Holocene epoch and show that amplitude frequency intensified this period, driven by an increase in extreme Niño events. Our combines new model simulations, advances coral proxy system modeling, data from central tropical Pacific. Although diverges observed...
Abstract El Niño‐Southern Oscillation (ENSO) variability affects year‐to‐year changes in North American hydroclimate. Extra‐tropical teleconnections are not always consistent between Niño events due to stochastic atmospheric and diverse sea surface temperature anomalies, making it difficult quantify using only instrumentally‐based records. Here we use two paleoclimate data assimilation (DA) products spanning the Last Millennium (LM) compare amplitudes frequencies of during pre‐industrial...
Abstract The Mississippi River represents a major commercial waterway, and periods of anomalously low river levels disrupt riverine transport. These low-flow events occur periodically, with recent event in the fall 2022 slowing barge traffic generating sharp increases transportation costs. Here we combine instrumental gage observations from lower output Community Earth System Model v2 Large Ensemble (LENS2) to evaluate historical trends future projections streamflow extremes, place broader...
Abstract The Himalayan mountain range produces one of the steepest and largest rainfall gradients on Earth, with >3 m/yr difference over a ∼100 km distance. Indian Summer Monsoon (ISM) contributes more than 80% to annual precipitation budget central Himalayas. remaining 20% falls mainly during pre‐ISM season. Understanding seasonal cycle transfer pathways moisture from rivers is crucial for constraining water availability in warming climate. However, partitioning into different storage...
Abstract Large uncertainties exist in climate model projections of the Asian summer monsoon (ASM). The El Niño‐Southern Oscillation (ENSO) is an important modulator ASM, but ENSO‐ASM teleconnection not stationary. Furthermore, teleconnections between ENSO and East versus South subcomponents ASM exhibit distinct characteristics. Therefore, understanding variability critical for anticipating future variations intensity. To this end, we here use paleoclimate records to extend temporal coverage...
General circulation models (GCMs) predict that the global hydrological cycle will change in response to anthropogenic warming. However, these predictions remain uncertain, particular for precipitation [IPCC, 2013]. Held and Soden [2006] suggest as lower-tropospheric water vapor concentration increases a warming climate, atmospheric convective mass fluxes weaken. Unfortunately, this process is difficult constrain, are poorly observed incompletely simulated GCMs. Here, we demonstrate stable...
Extreme precipitation events are one of the most consequential components climate change for society. The El Niño-Southern Oscillation (ENSO) is dominant mode variability in tropics and causes severe flooding drought many socioeconomically vulnerable regions. It remains unclear how tropical rainfall extremes ENSO changing response to anthropogenic forcing, demanding that we investigate relationships between precipitation, ENSO, external forcing past. Lake sediment records have provided...
Abstract The D/H ratio of epicuticular plant waxes ( δ D wax ) preserved in sedimentary archives is a powerful tool for paleoclimate reconstruction, but comparisons to other proxy records or climate model simulations requires system (PSM) that accounts transformations between precip and . Here we present new, publicly available PSM waxes, WaxPSM. WaxPSM predicts from observational data any isotope‐enabled modern, paleo, future experiment. values the C 29 n ‐alkane are calculated based on...