Physical Sciences and Mathematics Commons^™

Methanesulfonate In The Greenland Ice Sheet Project 2 Ice Core, E. S. Saltzman, P-Y. Whung, Paul Andrew Mayewski

Earth Science Faculty Scholarship

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean …

Major Features Of Glaciochemistry Over The Last 110,000 Years In The Greenland Ice Sheet Project 2 Ice Core, Qinzhao Yang, Paul Andrew Mayewski, Marks S. Twickler, Sallie Whitlow

Earth Science Faculty Scholarship

Major chemical species (Cl⁻, NO 3 - , SO 4 2 - , Na⁺, NH 4 + , K⁺, Mg²⁺, Ca²⁺) and δ¹⁸O covering the last 110,000 years from the Greenland Ice Sheet Project 2 (GISP2) ice core were utilized in this study in order to reconstruct the soluble chemistry of the atmosphere over Greenland and interpret major climate events that have affected the region. During the Holocene the major chemical species and δ¹⁸O do not display any significant relationship. However, a strong inverse correlation was …

Glaciochemistry Of Polar Ice Cores: A Review, Michel Legrand, Paul Andrew Mayewski

Earth Science Faculty Scholarship

Human activities have already modified the chemical composition of the natural atmosphere even in very remote regions of the world. The study of chemical parameters stored in solid precipitation and accumulated on polar ice sheets over the last several hundred thousand years provides a unique tool for obtaining information on the composition of the preindustrial atmosphere and its natural variability over the past. This paper deals with the chemistry of polar ice focused on the soluble mineral (Na⁺, NH₄⁺, K⁺, Ca⁺⁺, Mg⁺⁺, H⁺, F⁻, Cl …

Glaciochemical Studies At Siple Dome, West Antarctica, During The 1996–1997 Season, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow, L. David Meeker

Earth Science Faculty Scholarship

Deep ice cores collected from the interior of the west antarctic ice sheet and the interice stream ridges along the Siple Coast potentially contain long time-series records of Southern Hemisphere environmental change. One such location is Siple Dome, an approximately l20-kilometer (km) x 250-km ice dome located between ice streams C and D (figure 1). Because of promising results from reconnaissance glaciochemical (Mayewski, Twickler, and Whitlow 1995) and geophysical (Raymond et al. 1995) research, current U.S. deep ice-coring efforts are focused in the area. Drilling at Siple Dome is advantageous for several reasons, including the site's relatively simple geometry and …

Historical Biomass Burning: Late 19th Century Pioneer Agriculture Revolution In Northern Hemisphere Ice Core Data And Its Atmospheric Interpretation, G. Holdsworth, K. Hiuchi, G. A. Zielinski, Paul Andrew Mayewski, M. Wahlen, B. Deck, P. Chylek, B. Johnson, P. Damiano

Earth Science Faculty Scholarship

Ice core data from Yukon and Greenland spanning from ∼1750 to 1950 indicate that between ∼1850 and ≤1910 a clear atmospheric signal exists of an episodic biomass burning event that is referred to as the Pioneer Agriculture Revolution. This is best seen in NH₄⁺ ion and particulate concentrations but also in some limited black carbon concentration data, where for all three quantities maximum levels reach about 3 times the prerevolution background concentrations. Tree cellulose δ¹³C data and some early, controversial, French, air CO₂ data, occurring within the same time interval, are interpreted as providing other …

Depletion Of Atmospheric Nitrate And Chloride As A Consequence Of The Toba Volcanic Eruption, Q. Yang, Paul Andrew Mayewski, G. A. Zielinski, M. Twickler, K. C. Taylor

Earth Science Faculty Scholarship

Continuous measurements of SO₄²⁻ and electrical conductivity (ECM) along the GISP2 ice core record the Toba mega‐eruption at a depth 2590.95 to 2091.25 m (71,000±5000 years ago). Major chemical species were analyzed at a resolution of 1 cm per sample for this section. An ∼6‐year long period with extremely high volcanic SO₄²⁻ coincident with a 94% depletion of nitrate and 63% depletion of chloride is observed at the depth of the Toba horizon. Such a reduction of chloride in a volcanic layer preserved in an ice core has not been observed in any previous studies. The …

Relationship Between Continuous Aerosol Measurements And Firn Core Chemistry Over A 10‐Year Period At The South Pole, M. H. Bergin, E. A. Meyerson, J. E. Dibb, Paul Andrew Mayewski

Earth Science Faculty Scholarship

Before ice core chemistry can be used to estimate past atmospheric chemistry it is necessary to establish an unambiguous link between concentrations of chemical species in the air and snow. For the first time a continuous long‐term record of aerosol properties (aerosol light scattering coefficient, σ_sp , and Ångström exponent, å) at the South Pole are compared with the chemical record from a high resolution firn core (∼10 samples per year) covering the period from 1981 to 1991. Seasonal signals in å, associated with winter minima due to coarse mode seasalt and summer maxima due to accumulation mode sulfate …

Chemical Species Spatial Distribution And Relationship To Elevation And Snow Accumulation Rate Over The Greenland Ice Sheet, Q. Yang, Paul Andrew Mayewski, E. Linder, S. Whitlow, M. Twickler

Earth Science Faculty Scholarship

Major chemical species (Cl⁻, NO⁻₃, SO²⁻₄, Na⁺, K⁺, Mg²⁺, Ca²⁺) from 24 snowpits (sampled at a resolution of 3 cm, total 2995 samples) collected from northern, central, and southern Greenland were used for this investigation. The annual and seasonal (winter and summer) concentration of each chemical species was calculated and used to study the spatial distribution of chemical species over the central portion of the Greenland Ice Sheet. A two-sided t-distribution test (α=0.05) suggests that concentrations of major chemical species in snow do …

Twin Ice Cores From Greenland Reveal History Of Climate Change, More, R. Alley, Paul Andrew Mayewski, D. Peel, B. Stauffer

Earth Science Faculty Scholarship

Two projects conducted from 1989 to 1993 collected parallel ice cores—just 30 km apart— from the central part of the Greenland ice sheet. Each core is more than 3 km deep and extends back 110,000 years. In short, the ice cores tell a clear story: humans came of age agriculturally and industrially during the most stable climatic regime recorded in the cores. Change—large, rapid, and global—is more characteristic of the Earth's climate than is stasis.

Potential Atmospheric Impact Of The Toba Mega‐Eruption ∼71,000 Years Ago, G. A. Zielinski, Paul Andrew Mayewski, L. D. Meeker, S. Whitlow, M. S. Twickler, K. Taylor

Earth Science Faculty Scholarship

An ∼6‐year long period of volcanic sulfate recorded in the GISP2 ice core about 71,100 ± 5000 years ago may provide detailed information on the atmospheric and climatic impact of the Toba mega‐eruption. Deposition of these aerosols occur at the beginning of an ∼1000‐year long stadial event, but not immediately before the longer glacial period beginning ∼67,500 years ago. Total stratospheric loading estimates over this ∼6‐year period range from 2200 to 4400 Mt of H₂SO₄ aerosols. The range in values is given to compensate for uncertainties in aerosol transport. Magnitude and longevity of the atmospheric loading may …

A Century Of Accumulation And Temperature Changes In Dronning Maud Land, Antarctica, Elisabeth Isaksson, Wibjörn Karlén, Niels Gundestrup, Paul Andrew Mayewski, Sallie Whitlow, Mark Twickler

Earth Science Faculty Scholarship

A mass balance program was initiated in the Vestfjella-Heimefrontfjella area of western Dronning Maud Land during the austral summer of 1988–1989. As a part of this program, spatial and temporal variations in snow accumulation and temperature/stable isotopes are measured using shallow firn cores. In this paper we present surface accumulation data and discuss the climatic implications of the stable isotope records from two shallow firn cores. One 30-m-deep core, obtained about 200 km from the coast at 700 m asl (73°36′S, 12°26′W), covers the period 1932–1991. The other core was drilled at about 500 km from the coast at 2900 …

Ice-Core Glaciochemical Reconnaissance In Inland West Antarctica, Karl J. Kreutz, Paul Andrew Mayewski, Mark S. Twickler, Sallie I. Whitlow

Earth Science Faculty Scholarship

To date, the highest resolution ice cores have come from Greenland [the U.S. Greenland Ice Sheet Project 2 (GISP2) and European Greenland Ice Core Project (GRIP)]. The ability to determine annual layering in these cores over at least the past 50,000 years has allowed the reconstruction of a detailed environmental history covering major glacial and interglacial climatic events (e.g., Mayewski et aI. 1994; O'Brien et al. 1995). Although these cores have significantly advanced our understanding of paleoclimatic change in the Northern Hemisphere, questions remain as to whether the two hemispheres have responded synchronously to climate forcing through time. Determining the …

Global Perspective Of Nitrate Flux In Ice Cores, Qinzhao Yang, Paul Andrew Mayewski, Sallie Whitlow, Michael Morrison, Robert Talbot, Jack Dibb, Ernst Linder

Earth Science Faculty Scholarship

The relationships between the concentration and the flux of chemical species(Cl^-, NO₃^-, SO₄^2-, Na⁺, K⁺, NH₄⁺, Mg²⁺, Ca²⁺) versus snow accumulation rate were examined at GISP2 and 20D in Greenland, Mount Logan from the St. Elias Range, Yukon Territory, Canada, and Sentik Glacier from the northwest end of the Zanskar Range in the Indian Himalayas. At all sites, only nitrate flux is significantly(α = 0.05) related to snow accumulation rate. Of all the chemical series, only nitrate concentration data are normally …

Changes In Continental And Sea-Salt Atmospheric Loadings In Central Greenland During The Most Recent Deglaciation: Model-Based Estimates, R. B. Alley, R. C. Finkel, K. Nishizumi, A. Anandakrishnan, C. A. Shuman, G. Mershon, G. A. Zielinski, Paul Andrew Mayewski

Earth Science Faculty Scholarship

By fitting a very simple atmospheric impurity model to high-resolution data on ice accumulation and contaminant f1uxes in the GISP2 ice core, we have estimated changes in the atmospheric concentrations of soluble major ions, insoluble particulates and ¹⁰Be during the transition from glacial to Holocene conditions. For many species, changes in concentration in the ice typically overestimate atmospheric changes, and changes in flux to the ice typically underestimate atmospheric changes, because times of increased atmospheric contaminant loading are also times of reduced snowfall. The model interpolates between the flux and concentration records by explicitly allowing [or wet- and dry- …

Climatic Impact Of The A.D. 1783 Asama (Japan) Eruption Was Minimal: Evidence From The Gisp2 Ice Core, G. A. Zielinski, R. J. Fiacco, Paul Andrew Mayewski, L. D. Meeker, S. Whitlow, M. S. Twickler, M. S. Germani, K. Endo, M. Yasui

Earth Science Faculty Scholarship

Assessing the climatic impact of the A.D. 1783 eruption of Mt. Asama, Japan, is complicated by the concurrent eruption of Laki, Iceland. Estimates of the stratospheric loading of H₂SO₄ for the A.D. 1108 eruption of Asama derived from the SO₄²⁻ time series in the GISP2 Greenland ice core indicate a loading of about 10.4 Tg H₂SO₄ with a resulting stratospheric optical depth of 0.087. Assuming sulfur emissions from the 1783 eruption were only one‐third of the 1108 event yields a H₂SO₄ loading value of 3.5 Tg and a stratospheric …

Record Drilling Depth Struck In Greenland, Paul Andrew Mayewski, M. S. Twickler, J. E. Dibb, M. Wumkes, J. Klinck, J. S. Putscher, K. C. Taylor, D. A. Meese, E. D. Waddington, R. B. Alley, P. M. Grootes, M. Ram, M. Wahlen, A. T. Wilson

Earth Science Faculty Scholarship

On July 1, 1993, after 5 years of drilling, the Greenland Ice Sheet Project (GISP2) penetrated several meters of silty ice and reached bedrock at a depth of 3053.4 m. It then penetrated 1.5 m into the bedrock, producing the deepest ice core ever recovered (Figure 1).

In July 1992, a nearby European ice coring effort, the Greenland Ice Core Project (GRIP), reached an ice depth of 3028.8 m, providing more than 250,000 years of record. Comparisons between these ice core records have already demonstrated the remarkable reproducibility of the upper ∼90% of the records unparalleled view of climatic and …

Two-Hundred-Year Record Of Biogenic Sulfur In A South Greenland Ice Core (20d), P. Y. Whung, E. S. Saltzman, M. J. Spencer, Paul Andrew Mayewski, N. Gundestrup

Earth Science Faculty Scholarship

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core(20D). This study provides a high-resolution record of the DMS-derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb(σ = 2.38 ppb,n = 1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non-sea-salt sulfate (nss SO₄^2-), which increases dramatically after 1900 due to …

Regional Distribution Of Monsoon And Desert Dust Signals Recorded In Asian Glaciers, Cameron P. Wake, Paul Andrew Mayewski, Xie Zichu, Wang Ping, Li Zhongquin

Earth Science Faculty Scholarship

Short‐term (6 months to 17 years) glaciochemical records have been collected from glacier basins throughout the mountains of central Asia. The spatial distribution of snow chemistry in central Asia is controlled predominantly by the influx of dust from the arid and semi‐arid regions in central Asia. The glaciochemical data suggests 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 …

Methanesulfonic Acid In Coastal Antarctic Snow Related To Sea‐Ice Extent, K. A. Welch, Paul Andrew Mayewski, S. I. Whitlow

Earth Science Faculty Scholarship

Proxy records of biogenic sulfur gas obtained from ice cores suggest that variability in marine biogenic sulfur emissions may reflect changes in climate [Saigne and Legrand, 1987; Legrand et al., 1988, Legrand et al., 1991; Anderson and Charlson, 1991]. Increased sea‐ice extent has previously been proposed as one cause of relatively high methanesulfonic acid (MSA) in glacial‐age ice core samples [Gibson et al., 1990]. We have analyzed MSA, one of the oxidation products of the biogenic sulfur gas dimethylsulfide [Hatakeyama et al., 1985], from snowpit samples recovered from a coastal site in Southern Victoria Land, Antarctica. Time series of MSA …

Greenland Ice Core Greenland Ice Core "Signal" Characteristics: An Expanded View Of Climate Change, Paul Andrew Mayewski, L. D. Meeker, M. C. Morrison, M. S. Twickler, S. I. Whitlow, K. K. Ferland, D. A. Meese, M. R. Legrand, J. P. Steffensen

Earth Science Faculty Scholarship

The last millenium of Earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity. We have analyzed the major ions contained in the Greenland Ice Sheet Project 2 (GISP 2) ice core from the present to ∼674 A.D. to yield an environmental reconstruction for this period that includes a description of nitrogen and sulfur cycling, volcanic emissions, sea salt and terrestrial influences. We have adapted and extended mathematical procedures for extracting sporadic (e.g., volcanic) events, secular trends, and periodicities found in the data sets. Finally, by not assuming that periodic components …

The Spatial Variation Of Asian Dust And Marine Aerosol Contributions To Glaciochemical Signals In Central Asia, C. P. Wake, Paul Andrew Mayewski

Earth Science Faculty Scholarship

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 …

Anthropogenic Sulfate And Asian Dust Signals In Snow From Tien Shan, Northwest China, Cameron P. Wake, Paul Andrew Mayewski, Wang Ping, Yang Qinzhao, Han Jiankang, Xie Zichu

Earth Science Faculty Scholarship

Snow samples were collected from a 0.5 m snowpack at Glacier No. 1 and near Bogda Feng, eastern Tien Shan, northwest China. Samples that were melted in the field were analyzed for chloride, nitrate, sulfate, sodium, potassium, magnesium, calcium, and microparticles. Eight samples were returned frozen and were analyzed for the above ions plus ammonium, acetate, formate, methylsulfonate, and hydrogen peroxide. There was no significant difference in measured major ion concentrations between the melted and frozen samples. Measured cations in both sets of samples were two to three times greater than measured anions. Calcium and sodium are the dominant cations …

Ice-Core Dating And Chemistry By Direct-Current Electrical Conductivity, Kenorick Taylor, Richard Alley, Joe Fiacco, Pieter Grootes, Gregg Lamorey, Paul Andrew Mayewski, Mary Jo Spencer

Earth Science Faculty Scholarship

Although quantitative interpretation of the low-frequency electrical conductivity of ice cores from central Greenland is complicated by temperature variations of the measured core, annual layers can be recognized in sections of the core that are not impacted by non-seasonal features. Ambiguities in counting of annual layers can be minimized by comparing the electrical conductivity measurements to measurements of dust concentration and visual stratigraphy. A non-linear relationship between applied voltage and the current measured across two electrodes complicates the quantitative comparison of measurements made with different equipment, but does not affect the overall shape of the observed features .

Volcanic Ash From The 1362 A.D. Oræfajokull Eruption (Iceland) In The Greenland Ice Sheet, J. M. Palais, K. Taylor, Paul Andrew Mayewski, P. Grootes

Earth Science Faculty Scholarship

A continuous record of electrical conductivity measurements (ECM) was made on site during the drilling of a 200 m ice core at Summit, Greenland and was used to identify horizons in the ice that might be linked to volcanic eruptions. In one detailed section that we studied a large peak in the number of particles, two orders of magnitude above the background, was measured. The particle peak was not associated with an ECM peak, however. The particles were identified as volcanic ash on the basis of both particle morphology and chemical composition. The ash composition suggests an explosive rhyolitic eruption …

A Northern Hemisphere Volcanic Chemistry Record (1869-1984) And Climatic Implications Using A South Greenland Ice Core, W. B. Lyons, Paul Andrew Mayewski, M. J. Spencer, M. S. Twickler, T. E. Graedel

Earth Science Faculty Scholarship

The effect of volcanic emISSIOn of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the …

Detailed Glaciochemical Investigations In Southern Victoria Land, Antarctica — A Proxy Climate Record, Paul Andrew Mayewski

Earth Science Faculty Scholarship

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 …

A 1400-Year Oxygen Isotope History From The Ross Sea Area, Antarctica, P. M. Grootes, M. Stuiver, T. L. Saling, Paul Andrew Mayewski, M. J. Spencer, R. B. Alley, D. Jenssen

Earth Science Faculty Scholarship

Four ice cores from the Ross Sea drainage, Antarctica, show patterns of δ¹⁸O variations on a time scale of decades to centuries over the last 1400 years without change in the long-term average δ¹⁸O. Century scale δ¹⁸O fluctuations in the two cores drilled in the Ross Ice Shelf at Station J-9 (82° 23' S, 168° 38' W, elevation 60 m) are highly correlated (P < 2 x 10^-4). The long isotope record (>30 000 a) of the 1978 1-9 core thus represents local conditions over at least 102 m and on time scales of 100 …

A Review Of Central Asian Glaciochemical Data, Cameron P. Wake, Paul Andrew Mayewski, Mary Jo Spencer

Earth Science Faculty Scholarship

The glaciers of central Asia provide suitable locations from which to recover continuous, high-resolution glaciochemical records on a continental scale. Although the glaciochemical investigations undertaken to date in central Asia are few in number and limited in terms of spatial coverage and length of record, some preliminary observations can be made concerning regional and seasonal trends in snow chemistry in this region.
The sodium chloride ratio for most snow samples collected in central Asia approaches the ratio found in sea water (0.86 in μeq kg^-1), reflecting a marine source for these constituents. Sodium and chloride concentrations are, on …

A Glaciochemical Survey Of The Summit Region, Greenland, Paul Andrew Mayewski, M. J. Spencer, M. S. Twickler, S. Whitlow

Earth Science Faculty Scholarship

Spatial representativeness and an understanding of controls on chemical species distribution are essential requirements of any significant ice core investigation. Snowpit studies provide an essential tool in this process. In preparation for the central Greenland deep drilling effort a series of snowpits was sampled in detail for oxygen isotopes, major anions, major cations, total acidity and radionuclides. The results of this sampling program are used to define: (I) the chemical composition of the snow in the region, (2) the input timing and spatial distribution of major chemical species, (3) the potential dependence of species concentration on accumulation rate, and (4) …

The Dominion Range Ice Core, Queen Maud Mountains, Antarctica—General Site And Core Characteristics With Implications, Paul Andrew Mayewski, Mark S. Twickler, William Berry Lyons, Mary Jo Spencer, Debra A. Meese, Anthony J. Gow, Pieter Grootes, Todd Sowers, M. Scott Watson, Eric Saltzman

Earth Science Faculty Scholarship

The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including …