COLLABORATIVE RESEARCH: A Glaciochemical Record of Natural and Anthropengic Environmental Change in the Northwestern North American Arctic

This is a collaborative proposal between the Universities of New Hampshire and Maine and the Geological Survey of Canada. This Office of International Science and Engineering is contributing to this award. The Principal Investigators will recover two ice cores the Eclipse Icefield (3100 meters) in the St. Elias Mountains, Yukon Territory, Canada in cooperation with the Geological Survey of Canada in 2002. The core will be analyzed for stable isotopes, major ions, trace elements, rare earth elements and persistent organic pollutants. The Eclipse record will provide, for the first time, detailed depositional histories of a wide variety of pollutants during the last 200 years in the remote northwest North American Arctic. Through the use of unique chemical tracers, the Principal Investigators will be able to identify source regions for these pollutants, changes in source regions with time, and the role of atmospheric circulation in controlling contaminant distributions in the northwest North American Arctic. The detailed multi-parameter record of natural and anthropogenic change will result in a greatly improved record of climate and environmental change for a region in which very few records currently exist

COLLABORATIVE RESEARCH: Drillsite Reconnaissance and Snow Chemistry Survey in Denali National Park

This is a collaborative proposal by Principal Investigators from the Universities of New Hampshire (UNH) and Maine. Understanding the mechanisms responsible for interannual to decadal-scale climate variability during the late Holocene remains a fundamental research problem in Arctic science. The Principal Investigator\u27s will: 1) perform a detailed reconnaissance to identify suitable locations in Denali National Park (DNP) from which to recover and develop high resolution ice core records; and (2) develop detailed snow chemistry records that document the spatial (both horizontally and vertically) and seasonal variation of major ion and trace element deposition in the region. This will be the first step toward recovering surface-to-bedrock ice cores from DNP that can be used to reconstruct central Alaskan climate change over the last several thousand years. To determine the optimal drill site in DNP, our field season is devoted to reconnaissance activities at two or potential drilling locations, including ground penetrating radar profiles, GPS grid surveys, and sample collection from snowpit and shallow firn cores. All snow and firn samples will be analyzed for stable water isotopes (18O and D), major ions (Na+, Mg2+, Ca2+, K+, NH4+, Cl-, NO4 -, SO42-), trace elements (Al, Fe, Pb, Zn, Hg, Cd, Cu, V, Mn, Ni, As, Se), and rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu).Intellectual merit: The proposed suite of measurements will provide the most detailed data quantifying the spatial gradients in snow accumulation and snow chemistry above 3000 m in the region, as well as identifying the elevation above which strong seasonal signals in snow chemistry are preserved. In addition to providing them with critical data to select the optimal site(s) from which to recover surface-to-bedrock ice cores, the data set can be sued to answer a variety of questions including the following: What is the relative flux of pollutants in DNP compared to other glaciers across the Arctic? What is the primary pollution source for metals deposited in DNP? Is there a seasonal fluctuation in pollution sources and concentrations? What is the pollution signature of local (mountaineering) activities on Denali?Broader impacts of the proposed research: Research results will contribute to an improved understanding of the spatial and seasonal variation in snow accumulation and snow chemistry in DNP. The results will be used in undergraduate and graduate courses at U of Maine and UNH, and will be disseminated to the general public via established outreach programs at both institutions. Two graduate students will be trained as part of this project, and undergraduate students will be involved in the research at both institutions. Finally, the Principal Investigators will collaborate on the development of outreach products with Murie Science and Learning Center in DNP through a proposal they will be submitting to Discover Denali Research Fellowship Program

Acquisition of a High Resolution ICP-MS for Environmental Research and Training in Maine

This award provides support to significantly enhance the elemental and isotopic analysis capabilities at the University of Maine through the acquisition of a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). The HR-ICP-MS will enable environmental scientists and students at UMaine, as well as other educational institutions and state agencies, to substantially broaden their interdisciplinary research interests far beyond the current possibilities. Specifically, a state-of-the-art HR-ICP-MS will enable the PIs to: 1) Dramatically expand our element concentration and element ratio analysis capabilities in aqueous matrices. Existing UMaine research strengths in Quaternary science, environmental geochemistry, and marine biogeochemistry rely upon accurate elemental determinations at part-per-trillion and part-per-quadrillion levels. Each of these programs requires the sensitivity and low detection limits offered by HR-ICP-MS to perform multi-elemental analyses without time-consuming pre-concentration protocols; and 2) Perform rapid and highly precise elemental isotope ratio determinations, or constrain isotope ratios sufficiently for primary processes to be inferred. Isotope measurements made with the HR-ICP-MS will be immediately used in several ongoing projects investigating pollutant source and transport, biogeochemical processes, and climate variability. We will develop a HR-ICP-MS Facility in the Sawyer Environmental Research Center at UMaine for use as a regional resource. We plan to acquire a Finnigan ELEMENT2, the only commercially available high resolution single collector ICP-MS. In addition to its primary research focus, the HR-ICP-MS will be used in a range of undergraduate and graduate programs at UMaine. Integration of research and education will occur through graduate theses, undergraduate courses, and independent undergraduate research projects under the Honors Program and Capstone Experience program

Collaborative Research: Paleoclimate and Glaciological Recontructions in Central Asia

This project resulted in the collection of two intermediate-length (165 m) ice cores from the Inilchek Glacier, Central Tien Shan Mountains, Kyrgyzstan, during July/August 2000 with colleagues from UCSB, UNH, and the USGS. In addition, precipitation, fresh snow, surface snow, and aerosol samples were collected on the glacier and in the Inilchek Valley to assess atmospheric chemistry and deposition processes. The overall goal of the project (including a pending NSF/DOE proposal) is to develop high-resolution paleoclimatic records covering the last 1000-2000 years, which will be calibrated with meteorological data from the robust station network in the former Soviet Central Asian countries

Dry Valleys Late Holocene Climate Variability

This award supports a project to collect and develop high-resolution ice core records from the Dry Valleys region of Antarctica, and provide interpretations of interannual to decadal-scale climate variability during the last 2000 years (late Holocene). The project will test hypotheses related to ocean/atmosphere teleconnections (e.g., El Nino Southern Oscillation, Antarctic Oscillation) that may be responsible for major late Holocene climate events such as the Little Ice Age in the Southern Hemisphere. Conceptual and quantitative models of these processes in the Dry Valleys during the late Holocene are critical for understanding recent climate changes, and represent the main scientific merit of the project. We plan to collect intermediate-length ice cores (100-200m) at four sites along transects in Taylor Valley and Wright Valley, and analyze each core at high resolution for stable isotopes (d18O, dD), major ions (Na+, Mg2+, Ca2+, K+, NH4+, Cl-, NO3-, SO42-, MSA), and trace elements (Al, Fe, S, Sr, B). A suite of statistical techniques will be applied to the multivariate glaciochemical dataset to identify chemical associations and to calibrate the time-series records with available instrumental data. Broader impacts of the project include: 1) contributions to several ongoing interdisciplinary Antarctic research programs; 2) graduate and undergraduate student involvement in field, laboratory, and data interpretation activities; 3) use of project data and ideas in several UMaine courses and outreach activities; and 4) data dissemination through peer-reviewed publications, UMaine and other paleoclimate data archive websites, and presentations at national and international meetings

GPR Reflection Profiles of Clark and Commonwealth Glaciers, Dry Valleys, Antarctica

Englacial horizons deeper than 100 m are absent within 100 MHz ground-penetrating radar (GPR) surface profiles we recorded on Clark and Commonwealth Glaciers in the Antarctic Dry Valleys region. Both glaciers show continuous bottom horizons to 280 m, with bottom signal-to-noise ratios near 30 dB. Density horizons should fade below 50 m depth because impermeable ice occurred by 36 m. Folding within Commonwealth Glacier could preclude radar strata beneath about 80 m depth, but there is no significant folding within Clark Glacier. Strong sulfate concentrations and contrasts exist in our shallow ice core. However, it appears that high background concentration levels, and possible decreased concentration contrasts with depth placed their corresponding reflection coefficients at the limit of, or below, our system sensitivity by about 77 m depth. Further verification of this conclusion awaits processing of our deep-core chemistry profiles

Limited migration of soluble ionic species in a Siple Dome, Antarctica, ice core

High-resolution (\u3e10 samples a−1) glaciochemical analyses covering the last 110 years from a Siplc Dome, Antarctica, ire core reveal limited migration of certain soluble ionic species (methane sulfonic acid, NO3 − and Mg2+). The observed chemical migration may be due in part to seasonal alternation between less acidic winter (from high sea-salt concentrations) and more acidic summer (from high marine biogenic acid concentrations) layers, common at coastal siles such as Siplc Dome. Exact mechanisms to expla in the migration are unclear, although simple diffusion and gravitational movement are unlikely since new peaks are formed where none previously existed in each case. Initial migration of each species is both shallower and earlier at Siple Dome than at other sites in Antarctica where similar phenomena have been observed, which may be related to the relatively low accumulation rate at Siple Dome (~13.3 cm ice a−1). Migration appears to be limited to either the preceding or following seasonal layer for each species, suggesting that paleoclimatic interpretations based on dala with lower than annual resolution are not likely to be affected

Collaborative Research: Asian Ice Core Array (AICA)--Reconstruction of Past Physical and Chemical Climate over Asia

Funding is provided to help the researchers build on success using ice cores for understanding past physical and chemical climate change from Antarctica, Arctic, North Pacific and Asia by analyzing and interpreting a new array of Asian ice cores. The researchers plan to use five existing ice cores and collect one new ice core to enhance the reconstruction of environmental conditions over Asia. The primary research questions for the Asian Ice Core Array (AICA) research include: (1) Asian climate variability - How do major Asian circulation features (i.e., Asian monsoon, Westerlies, polar air masses, Siberian and Tibetan Highs) vary on annual to longer scales? What factors (i.e., solar variability, volcanic activity, greenhouse gases) control changes in the major circulation features impacting Asia? What is the association between Asian climate and global circulation features? Can Asian climate be simulated and predicted from the state of past atmospheric circulation patterns (analog modeling)? How does the interaction between tropical and extra-tropical circulation impact climate over Asia? What are the regional climatic changes to be expected in near future based on trends? Are Asian climate change events related to climate change in other regions?(2) Environmental change over Asia - How have natural versus anthropogenic sources for chemical species notably sulfate, nitrate, and select heavy metals and trace and major elements varied in the atmosphere over central Asia? Are spatial and temporal variations in contaminants related to changes in contaminant source areas or production? Have changes in atmospheric circulation impacted distribution of chemical species in the atmosphere over central Asia?Scientifically, ice cores from Asian glaciers could provide a source of high-resolution records of seasonal to millennial climate dynamics and atmospheric chemistry. This is important because the Eurasian continent is the largest landmass in the World and exerts substantial influence on atmospheric and terrestrial systems and the 2.5 billion people living in the region. Changes in environment over this region could have dramatic impacts on humans and ecosystems. Unpredictable changes in water resources and desertification over this heavily populated region may have significant global consequences. The results from AICA could be of interest to climatologists, paleoclimatologists, atmospheric chemists, geochemists, climate modelers, solar-terrestrial physicists, and environmental statisticians. Educationally, the research project will support two PhD students as well as several undergraduate students for three years. This will help provide a rich research experience for the graduate and undergraduate students. Also, this project has strong ties to colleagues in China and Europe and offers intellectual and financial leveraging to aid in the success of the project

The effect of spatial and temporal accumulation rate variability in west Antarctica on soluble ion deposition

Annually‐dated snowpit and ice core records from two areas of West Antarctica are used to investigate spatial accumulation patterns and to evaluate temporal accumulation rate/glaciochemical concentration and flux relationships. Mean accumulation rate gradients in Marie Byrd Land (11–23 gcm−2yr−1 over 150 km, decreasing to the south) and Siple Dome (10–18 gcm−2yr−1 over 60 km, decreasing to the south) are consistent for at least the last several decades, and demonstrate the influence of the offshore quasi‐permanent Amundsen Sea low pressure system on moisture flux into the region. Local and regional‐scale topography in both regions appears to affect orographic lifting, air mass trajectories, and accumulation distribution. Linear regression of mean annual soluble ion concentration and flux data vs. accumulation rates in both regions indicates that 1) concentrations are independent of and thus not a rescaling of accumulation rate time‐series, and 2) chemical flux to the ice sheet surface is mainly via wet deposition, and changes in atmospheric concentration play a significant role. We therefore suggest that, in the absence of detailed air/snow transfer models, ice core chemical concentration and not flux time‐series provide a better estimate of past aerosol loading in West Antarctica

Impact of Preindustrial Biomass-Burning Emissions on the Oxidation Pathways of Tropospheric Sulfur and Nitrogen

Ice core measurements (H2O2 and CH4/HCHO) and modeling studies indicate a change in the oxidation capacity of the atmosphere since the onset of the Industrial Revolution due to increases in fossil fuel burning emissions [e. g., Lelieveld et al., 2002; Hauglustaine and Brasseur, 2001; Wang and Jacob, 1998; Staffelbach et al., 1991]. The mass-independent fractionation (MIF) in the oxygen isotopes of sulfate and nitrate from a Greenland ice core reveal that biomass-burning events in North America just prior to the Industrial Revolution significantly impacted the oxidation pathways of sulfur and nitrogen species deposited in Greenland ice. This finding highlights the importance of biomass-burning emissions for atmospheric chemistry in preindustrial North America and warrants the inclusion of this impact in modeling studies estimating changes in atmospheric oxidant chemistry since the Industrial Revolution, particularly when using paleo-oxidant data as a reference for model evaluation