Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

Analysis Of A 290-Year Net Accumulation Time Series From Mt. Logan, Yukon, G. Holdsworth, H. R. Krouse, M. Nosal, M. J. Spencer, Paul Andrew Mayewski

Earth Science Faculty Scholarship

A 102.5-m mechanically continuous firn and ice core sequence retrieved from the Northwest Col of Mt. Logan (latitude 60°30'N; longitude 140°35'W; site location 5340 m a.s.l.) in the Yukon Territory, Canada, has been analyzed continuously for stable isotopes, pH and liquid electrolytic conductivity. Specific sections of the core have been analyzed for total β-activity (0-22 m) and trace ion concentrations (across major volcanic events) in order to date the core. In the lower half of the core, nitrate and some other ionic species are used to identify annual increments except between AD 1693 and AD 1720 and between AD 1729 …

Detailed Glaciochemical Investigations In Southern Victoria Land, Antarctica―A Proxy Climate Record, Paul Andrew Mayewski, Mark S. Twickler

Earth Science Faculty Scholarship

Advances in climate prediction depend on a knowledge of historical climatic sequences ranging in scale from decades to Millennia. Proxy data produced by pollen, sediment, tree rings,glacier fluctuations, and ice and snow cores are valuable in the construction of climatic sequences when direct observations of the atmosphere are either spatially or temporally lacking. Links between proxy data and the atmosphere generate the most confidence when actual components of climate are preserved in the proxy medium.

Ice-Core Records And Ozone Depletion—Potential For A Proxy Ozone Record, Paul Andrew Mayewski, Mary Jo Spencer, William Berry Lyons, Mark S. Twickler, J. Dibb

Earth Science Faculty Scholarship

Time-series of the ionic composition in polar ice cores can provide detailed direct and proxy records of seasonal to Millenial scale fluctuations in climate, atmospheric chemistry, and volcanic activity. Even though problems of species-source links and air/snow fractionation have not all been entirely resolved,the fact remains that ice cores currently hold the best hope of retrieving detailed paleo-atmospheric records. While direct links between the chemistry in ice cores and the ozone depletion phenomenon cannot be guaranteed, ice-core records provide the only means by which signals related to the ozone cycle can be produced for pre-measurement periods or for unmonitored sites. …

The Glaciochemistry Of Snowpits From Quelccaya Ice Cap, Peru, 1982, W. Berry Lyons, Paul Andrew Mayewski, Lonnie G. Thompson, Boyd Allen Iii

Earth Science Faculty Scholarship

We present glaciochemical data from a pilot study of two snow-pits from Quelccaya ice cap, Peruvian Andes. These are the first samples to be analyzed from Quelccaya for nitrate and sulfate by ion chromatography (IC), for nitrate-plus-nitrite, reactive silicate and reactive iron by colorimetry, and for sodium by atomic absorption spectrophotometry. The 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations.

Reactive iron, reactive silicate and sodium, and the profiles of …

Glaciochemical Studies And Estimated Net Mass Balances For Rennick Glacier Area, Antarctica, Boyd Allen Iii, Paul Andrew Mayewski, W. Berry Lyons, Mary Jo Spencer

Earth Science Faculty Scholarship

Two snow and ice cores from the Rennick Glacier area, Antarctica (study area center point lat 71° 15' S, long 162° 30' E) were analyzed for the chemical species: chloride, sodium, reactive silicate, sulfate and nitrate. Core E1O (6.35 m) was taken from Evans Névé, a large accumulation basin at the head of Rennick Glacier. Core M1 (4.35 m) was extracted from the accumulation zone on the central plateau of the Morozumi Range, a small mountain massif bordering Rennick Glacier. Cores E1O and M1 span the time periods from 1929 to 1981 and from 1971 to 1981, respectively, as dated …

Using An Ice Core To Characterize The Climatic History Of Antarctica, Paul Andrew Mayewski, W. B. Lyons

Earth Science Faculty Scholarship

Between 20 November and 14 December 1984, a remote tent camp was operated in the Dominion Range (center point, 85° 15' S 166° 10 'E) on an ice-covered massif located at the confluence of the heads of the Beardmore and Mill Glaciers in the Transantarctic Mountains. The camp was occupied by four members of the Glacier Research Group (University of New Hampshire) and three members of the Polar lee Coring Office (PICO) (University of Nebraska). The main task at the site was to retrieve an ice core from which chemical and physical time series will be made available to help …