475 research outputs found
The spatial variation of Asian dust and marine aerosol contributions to glaciochemical signals in central Asia
Short-term (6 months to 17 years) glaciochemical records have been collected from several glacier basins in the mountains of central Asia. The spatial distribution of snow chemistry in central Asia is controlled by the influx of dust from the large expanse of arid and semiarid regions in central Asia. Glaciers in the Northern and Western Tibetan Plateau show elevated concentrations and elevated annual fluxes of calcium, sodium, chloride, sulphate and nitrate due to the influx of desert dust from nearby arid and semi-arid regions. Glaciers in the Southeastern Tibetan Plateau show lower concentrations and lower annual fluxes of major ions due to longer transport distances of dust from the arid and semi-arid regions of Western China. Snow from the Karakoram and Western Himalaya show ion concentrations similar to those in Southeastern Tibetan Plateau, but much higher annual fluxes suggesting that much of the aerosol and moisture transported with the westerly jet stream is removed as it ascends the Southwest margin of the Tibetan Plateau. Snow from the Southern slopes of the Eastern Himalayas shows very low concentrations and very low annual fluxes of major ions, indicating that this region is relatively free from the chemical influence of Asian dust. The glaciochemical data suggest that glaciers which are removed from large source areas of mineral aerosol, such as those in the Himalaya, the Karakoram, and the Southeastern Tibetan Plateau, are the ones most likely to contain longer-term glaciochemical records which detail annual to decadal variation in the strength of the Asian monsoon and long-range transport of Asian dust
US ITASE Glaciochemistry Phase 2: East Antarctica
This award supports a project to undertake glaciochemical investigations of the Ross Sea Embayment Drainage System, and portions of Wilkes Land for purposes of understanding annual to multi-centennial scale climate variability. The glaciochemical data that will be collected will contribute to the U.S. component of the International Trans-Antarctic Scientific Expedition and will occur over a period of two years on an overland traverse that will begin at Taylor Dome in Northern Victoria Land and travel to the South Pole. This data, along with similar information collected on a series of earlier traverse in West Antarctica, will contribute to providing an in-depth understanding of natural climate variability and will provide a baseline for assessing modern climate variability in the context of human activity; and a contribution to the prediction of future climate variability. By choosing appropriate sites for sampling, the traverse will make important contributions to the understanding of the behavior of major atmospheric phenomena such as the Antarctic Oscillation, ENSO, and changes in the chemical composition of the atmosphere, plus controls on all of these changes. US ITASE research addresses important questions concerning the role of Antarctica in global change and will make an important contribution to IPY. Results are translated into publicly accessible information through lectures, media appearances, and a major outreach activity shared between the University of Maine and the Museum of Science (Boston). US ITASE activities provide material for curriculum development in K-12 education and university courses and opportunities for field and laboratory experiences for graduate and undergraduate students. The Climate Change Institute has a long history of gender and ethnically diverse student and staff involvement in research
Colle Gnifetti Ice Core (KCC) Progress Report (Year One)—Arcadia Ice Core Proposal: Initiatives on the Science of the Human Past
The Colle Gnifetti glacier of the Monta Rosa Massif on the Swiss-Italian border is perfectly situated to offer insight into the intersection of environment (climate) and culture (history of the economy, political stability, pollution, disease) in medieval Europe. While ice cores previously collected at Colle Gnifetti were sampled at state-of-the-art resolution for the time, it was nevertheless impossible to differentiate annual or finer layering in the period older than 1500 A.D. The 2013 Colle Gnifetti expedition thus sought to collect a new ice core that could be analyzed using the ultra-high-resolution laser based technology developed in the Climate Change Institute’s W.M. Keck Laser Ice Facility.a
A Science Management Office for the United States Component of the International Trans Antarctic Expedition (US ITASE SMO) - A Collaborative Program of Research from Taylor Dome to
This award supports the science management office (SMO) for a series of collaborative science proposals that are part of the U.S. contribution to the International Trans-Antarctic Scientific Expedition (US ITASE). It supports the science administration and the coordination of logistics needed in order to accomplish the research. The SMO will work with the Antarctic support contractor to coordinate field operations for the traverse platform so that US ITASE can undertake a series of scientific traverses in the region from Taylor Dome, in Northern Victoria Land to South Pole (NVL-SP) inclusive of interior portions of the East Antarctic plateau such as Dome A. US ITASE is the terrestrial equivalent of a polar research vessel. It offers the ground-based opportunities of traditional style over-snow travel coupled with the modern technology of GPS navigation, crevasse detecting radar, satellite communications, and multi-disciplinary research. By operating as a ground-based transport system US ITASE offers scientists the opportunity to experience the dynamic environment they are studying. US ITASE also provides a stimulating interactive venue for research similar to that afforded by oceanographic research vessels and large polar field camps, without the cost of the former or the lack of mobility of the latter. More importantly the combination of disciplines represented by US ITASE provides a unique, logistically efficient, multi-dimensional view of the atmosphere, the ice sheet and their histories. Data collected by US ITASE and its international partners is available to a broad scientific community and will contribute to many of the goals of the upcoming International Polar Year (IPY). US ITASE has an extensive program of public outreach and provides significant opportunities for many students to experience multidisciplinary Antarctic research
ITASE Synthesis Workshop
This award supports a workshop to bring together scientists involved in the International Trans-Antarctic Scientific Expedition (ITASE). Since 1999 the US has supported a program of traverses across both East and West Antarctica (US ITASE). US ITASE is part of the ITASE multi-national effort to understand the past 200-1000+ years of climate change over Antarctica and the Southern Ocean. ITASE is organized under the auspices of Scientific Committee for Antarctic Research (SCAR) and now comprises twenty-one countries. The international representatives from ITASE have met several times in the past to discuss national traverse plans; coordinate efforts; synthesize results; and develop statistical and other techniques for the interpretation of data. The workshop will provide additional momentum to the process of synthesizing the Antarctic-wide ITASE reconstruction of past climate. An emerging compilation of all ITASE and other ice core sites is available through the Ice READER database sponsored by SCAR and one workshop goal is to update this metadata listing. The workshop will also focus on identifying the characteristics of climate change that have impacted the Antarctic and surrounding ocean in the past 200-1000+ years in order to provide a basis for assessing the dramatic changes expected as a consequence of the ~4-6 degrees C warming projected for this region by the Inter-governmental Panel for Climate Change (IPCC). Results from this workshop will also form the basis for future collaborative efforts between ITASE ice core researchers, meteorologists, oceanographers, and climate modelers stemming from international initiatives such as the International Partnerships in Ice Core Sciences (IPICS) and the International Polar Year (IPY). Finally, workshop findings will be included in the forthcoming document: Antarctic Climate Change and the Environment initiated by SCAR
Paleoclimate from Mount Everest Ice Cores
The primary goal of this research is to analyze three ice cores collected by a joint Chinese-US team of researchers in the spring of 2001. At that time, a 117-meter ice core was recovered from the East Rongbuk (ERC) glacier at 6500 meters above sea level. In addition to these analyses, the researchers will participate in a joint Chinese-US expedition to the region to retrieve modern day glaciological and meteorological data to aid in the interpretation of the ice core data.Based on local accumulation rates and layer thinning estimates, the new 117-meter ERC core likely represents at least several centuries of snow deposition. Thus, the researchers have the opportunity to develop a calibrated, high-resolution paleoclimate record from the region that will complement previous paleoclimatological research from Mt. Everest and Central Asia.The analysis of the ice cores will focus on producing a detailed time-series of major ion concentrations (i.e., chloride, nitrate, sulfate, calcium, magnesium, sodium, potassium and ammonium), stable isotope ratios (i.e., oxygen and deuterium), and total element concentration (i.e., iron, aluminum, calcium, and sulfur). These data will be used to develop:-- high-resolution time series of Late Holocene climate variability for the region involving atmospheric circulation, temperature, and precipitation, and -- detailed environmental records of biomass burning, dust storms, anthropogenic pollutants, and marine and continental biogenic source productivity. The analyses of the ice cores could increase our understanding of the atmospheric dynamics of an important weather system that impacts a heavily populated region of the world. The interaction and cooperation of scientific colleagues from the United States and China will enhance the prospects for success
US ITASE Glaciochemistry
The UMaine Continuous ice core Melter (UMCoM) system is a modified Wagenbach-style continuous melter system (Rothlisberger et al., 2000) with three important differences. First, we have constructed the melthead as two separate pieces, a base and a melter plate, so that it can be easily dismantled and cleaned between melting sessions. Second, the melter plate in contact with the ice is composed of pure nickel (\u3e99.9% Ni) so that trace element measurements can be made from the meltwater stream. Third, in contrast to ice core melter systems in which the meltwater is directly channeled to online instruments for continuous flow analyses (e.g. Sigg et al., 1991; Rothlisberger et al., 2000; Huber et al., 2001; McConnell et al., 2002; Knusel et al., 2003), the UMCoM system collects discrete, high-resolution (\u3c1-2 cm/sample), co-registered samples for each chemical analysis under ultraclean conditions using three or more (if needed) Gilson® fraction collectors (a fraction collector is a device that automatically apportions a liquid flow into discrete samples based on volume). This third modification provides exceptional flexibility in tailoring specific chemical analyses to each project. Currently, the UMCoM system is producing samples from the 2001 Mt. Logan summit ice core for analysis of 30 trace elements (Ca, Al, Fe, S, Sr, Cs, Bi, U, Tl, As, Ti, V, Cr, Mn, Co, Cu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) by inductively coupled plasma mass spectrometry (ICP-MS), 8 major ions (Na+, Mg2+, K+, Ca2+, Cl-, SO4 2-, NO3 -, MSA) by ion chromatography (IC), stable water isotopes (δ18O, δD, d) by isotope ratio mass spectrometry (IRMS), and volcanic tephra. The list of analytes can be adjusted to address the specific needs of each project
Science Management for the United States Component of the International Trans-Antarctic Expedition
US ITASE is effectively a polar research vessel. It offers the ground-based opportunities of traditional style traverse travel coupled with the modern technology of GPS, crevasse detecting radar, satellite communications and multi-disciplinary research. By operating as a ground-based transport system US ITASE offers scientists the opportunity to experience the dynamic environment they are studying. US ITASE also offers an important interactive venue for research (currently eleven integrated science projects) similar to that afforded by oceanographic research vessels and large polar field camps, without the cost of the former or the lack of mobility of the latter. More importantly the combination of disciplines represented by US ITASE provides a unique, multi-dimensional (x, y, z and time) view of the ice sheet and its history. Over the past four field seasons (1999-2003) US ITASE sampled the environment of West Antarctica into East Antarctica over spatial scales of \u3e5000 km, depths of \u3e3000 m, heights in the atmosphere of \u3e20 km, and time periods of several hundred years (sub-annual scale) to hundreds of thousands of years (millennial scale)
Glacial Geologic Investigation of Upper Rennick Glacier Region, Northern Victoria Land
The 1974-1975 field season was spent investigating the upper Rennick Glacier area (figure) for (1) the relationship between the glacial history of the study area and the glacial histories already defined for more southerly sectors of the Transantarctic Mountains, (2) the history and dimensions of former fluctuations of the east antarctic ice sheet, Rennick Glacier, and its tributaries, as recorded in glacial deposits, and (3) the significance of this area in paleoclimatic reconstructions of Antarctica and the world
Detailed Glaciochemical Investigations in Southern Victoria Land, Antarctica — A Proxy Climate Record
The production of environmental change records using time-series data retrieved from ice cores has seen minimal application in the Transantarctic Mountains despite the existence of a well-developed lower resolution glacial geologic record for this area which forms the primary basis for understanding the glacial history of East Antarctica. In addition, records derived from marine and lake cores, glacier margin fluctuation studies, measures of volcanic activity, and meteorological data sets from within or close to the Transantarctic Mountains are available for comparison. This emerging environmental data-base provides the tools needed to define the change characteristics, over a period of thousands of years, of several major dynamic components in this region, e.g., climate, atmospheric chemistry, sea-ice extent, volcanic activity, and atmospheric turbidity
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