20D (Location--southern Greenland, 65.1o N, 44.87o W, elevation--2,625 masl) One 2.5 meter snow pit dug and sampled in 1984, 3 cm sampling interval Surface snow samples One core drilled summer 1984; 115 meters DATA SETS AVAILABLE: 2.5 M snow pit: Chemistry Traverse from Dye 3 to drill site: chemistry Surface snow samples: chemistry, some general weather observations Core: Chemistry, density The pit was dug and sampled at a 5 cm interval by the Glacier Research Group (GRG), using established protocols to prevent contamination. The samples for major ion chemistry remained frozen until melted for analysis in the GRG lab, located at the University of New Hampshire (UNH). The surface snow samples were collected by GRG, using established protocols to prevent contamination. The samples for major ion chemistry remained frozen until melted for analysis in the GRG lab. The core was drilled for GRG by the Polar Ice Coring Office (PICO). All core processing was done by GRG using established protocols to prevent contamination. The upper portion of the core, 0-70.59 meters was analyzed in 1984-1985. A subcorer was used on the firn, the ice samples were rinsed with ultra-pure water. Chemistry from these sections initially was Na, Cl, NO3 and SO4 and oxygen isotope data. The remaining core was sectioned and analyzed in 1989-1990. All samples were rinsed with ultrapure water. Chemistry from these sections consists of Cl, NO3, SO4, Na, NH4, K, Mg, Ca, and Fe. The refrozen remainders from the upper portion of the core was analyzed for the suite of 5 cations and for Fe. All data except the stable oxygen isotope data, which is from the Geophysical Isotope Laboratory, University of Copenhagen, was generated by GRG. Analytical methods: Initial major ion analyses (for the snow pit, surface snow samples and the 0-70.59 meter core processing) consisted of determination major anion concentrations (Cl, NO3, SO4) by ion chromatography and sodium (Na) by flameless atomic absorption spectrophotometry (AAS). Core samples processed in 1989 to 1990 were analyzed for major anions and major cations by ion chromatograpy. Iron (+3) was determined by flameless atomic absorption spectrophotometry on acidified (HNO3) 5 ml aliquots. The Fe concentration is the average of a minimum of 2 replicate analysis per sample. MSA was determined on samples by Pai Yei Whung at the University of Miami as part of her Ph.D. disseration. Contact: Sallie Whitlow, Glacier Research Group, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, New Hampshire 03824 603-862-4129 siw@unh.edu Dr. Paul Mayewski, Glacier Research Group, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, New Hampshire 03824 603-862-3146 Publications: Mayewski, P.A., W. B. Lyons, M. J. Spencer, M. Twickler, W. Dansgaard, B. Koci, C. I. Davidson, R. E. Honrath, 1986, Sulfate and nitrate concentrations from a south Greenland ice core. Science,232, 975-977. Twickler, M., M.J. Spencer, W. B. Lyons, P. A. Mayewski, 1986, Measurement of organic carbon in polar snow samples. Nature, 320, 156-158. Mayewski, P.A., M.J. Spencer, W. B. Lyons, and M. S. Twickler, 1987, Seasonal and spatial trends in south Greenland snow chemistry. Atmos. Environ. 21, 863-869. Mayewski, P.A., W. B. Lyons, M. J. Spencer, M. S. Twickler, C. F. Buck, and S. Whitlow, 1990. An ice-core record of atmospheric response to anthropogenic sulphate and nitrate. Nature, 346, 554-556. Mayewski, P.A., G. Holdsworth, M. J. Spencer, S. Whitlow, M. Twickler, M. C. Morrision, K. K. Ferland and L. D. Meeker, 1993. Ice-core sulfate from three northern hemisphere sites: source and temperature forcing implications. Atmos. Environ., 27A, 2915-2919. Whitlow, S., P. Mayewski, J. Dibb, G. Holdsworth, and M. Twickler, 1994, An ice-core-based record of biomass burning in the Arctic and subarctic, 1750-1980. Tellus, 46B, 234-242. Data Fields -999 indicates no data -888 indicates sample below the level of detection Precision is the average of the coefficient of variations calculted for each pair of duplicate aliquots analyzed. Snow_pit: Top depth, meters Bottom depth, meters Oxygen isotopes (18O), standard per mil notation Chloride (Cl), micrograms per liter; precision 3% Nitrate (NO3), micrograms/L; precision 5% Sulfate (SO4), micrograms/L; precision 3% Sodium (Na) by AAS, micrograms/L, precision 3% Surface snow: Date, day the snow sample was collected Snow type, description of the type of snow Oxygen isotopes (18O), standard per mil notation Sodium (Na) by AAS, micrograms per liter; precision 3% Chloride (Cl), micrograms per liter; precision 3% Nitrate (NO3), micrograms/L; precision 5% Sulfate (SO4), micrograms/L; precision 3% Traverse: Distance, Kilometers from the core drilling site Oxygen isotopes (18O), standard per mil notation Sodium (Na) by AAS, micrograms per liter; precision 3%; Chloride (Cl), micrograms /L; precision 3% Nitrate (NO3), micrograms/L; precision 5% Sulfate (SO4), micrograms/L; precision 3% 20D_Density: Top, meters Bottom, meters Density, grams per cubic centimeter 20D_core: Top, meters Bottom, meters Year, calender year; the year was subdivided using the oxygen isotope profile, it is not assumed that the samples are equally time spaced over the year Oxygen isotopes (18O), standard per mil notation Sodium (Na), micrograms per liter; precision 3%, detection limit 0.1, blank 4.12 Ammonium (NH4), micrograms/L, precision 6%, detection limit 0.2, blank 6.4 Potassium (K), micrograms/L, precision 10%, detection limit 0.1, blank 0.5 Magnesium (Mg), micrograms/L, precision 10%, detection limit 0.05, blank 2.6 Calcium (Ca), micrograms/L, precision 10%, detection limit 0.5, blank 7.7 Chloride (Cl), micrograms/L; precision 5%, detection limit 1.0; Nitrate (NO3), micrograms/L; precision 3%, detection limit 1.0; Sulfate (SO4), micrograms/L; precision 4%, detection limit 1.0; Iron, +3 (Fe), micrograms/L; precision 8%, detection limit 0.1 General comments on the core chemistry data The Na values reported are a mixture of the AAS and blank corrected IC values, the lowest of two values was chosen. The remainder of the cation values from 0-70.59 meters have been corrected by subtracting an average blank value (based on 44 blanks). The blanks were sample containers with ultrapure water that were treated like samples. When the blank overcorrected the values, (subtraction resulted in a negative number) detection limit values have been used. Comparison of the original AAS Na values and the IC Na values allowed elimiation of contaminated rerun samples (the if Na value for the rerun sample was greater than the original value by 50% it was considered contaminated). The NH4, K, Mg, and Ca values from this section of the core are generally correct but with large associated uncertainty. This is especially true of the NH4 values as NH4 is most sensitive to thawing and refreezing. Core processing blanks were analyzed only for Na, so the amount of K, Mg and Ca contamination from core processing is unknown.