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Full-Text Articles in Physical Sciences and Mathematics
A Simple Model To Estimate Atmospheric Concentrations Of Aerosol Chemical Species Based On Snow Core Chemistry At Summit, Greenland, M H. Bergin, C Davidson, Jack E. Dibb, J L. Jaffrezo, H D. Kuhns, S N. Pandis
A Simple Model To Estimate Atmospheric Concentrations Of Aerosol Chemical Species Based On Snow Core Chemistry At Summit, Greenland, M H. Bergin, C Davidson, Jack E. Dibb, J L. Jaffrezo, H D. Kuhns, S N. Pandis
Earth Sciences
A simple model is presented to estimate atmospheric concentrations of chemical species that exist primarily as aerosols based on snow core/ice core chemistry at Summit, Greenland. The model considers the processes of snow, fog, and dry deposition. The deposition parameters for each of the processes are estimated for SO42− and Ca2+ and are based on experiments conducted during the 1993 and 1994 summer field seasons. The seasonal mean atmospheric concentrations are estimated based on the deposition parameters and snow cores obtained during the field seasons. The ratios of the estimated seasonal mean airborne concentration divided by the …
Diel Variations Of H2o2 In Greenland: A Discussion Of The Cause And Effect Relationship, R Bales, Joe Mcconnell, Mark V. Losleben, Martha H. Conklin, Katrin Fuhrer, Albrecht Neftel, Jack E. Dibb, D W. Kahl, C Stearns
Diel Variations Of H2o2 In Greenland: A Discussion Of The Cause And Effect Relationship, R Bales, Joe Mcconnell, Mark V. Losleben, Martha H. Conklin, Katrin Fuhrer, Albrecht Neftel, Jack E. Dibb, D W. Kahl, C Stearns
Earth Sciences
Atmospheric hydrogen peroxide (H2O2) measurements at Summit, Greenland, in May–June, 1993 exhibited a diel variation, with afternoon highs typically 1–2 parts per billion by volume (ppbv) and nighttime lows about 0.5 ppbv lower. This variation closely followed that for temperature; specific humidity exhibited the same general trend. During a 17-day snowfall-free period, surface snow was accumulating H2O2, apparently from nighttime cocondensation of H2O and H2O2. Previous photochemical modeling (Neftel et al., 1995) suggests that daytime H2O2 should be about 1 ppbv, significantly lower …
The Contributions Of Snow, Fog, And Dry Deposition To The Summer Flux Of Anions And Cations At Summit, Greenland, M H. Bergin, J L. Jaffrezo, C Davidson, Jack E. Dibb, S N. Pandis, R Hillamo, W Maenhaut, H D. Kuhns, T Makela
The Contributions Of Snow, Fog, And Dry Deposition To The Summer Flux Of Anions And Cations At Summit, Greenland, M H. Bergin, J L. Jaffrezo, C Davidson, Jack E. Dibb, S N. Pandis, R Hillamo, W Maenhaut, H D. Kuhns, T Makela
Earth Sciences
Experiments were performed during the period May–July of 1993 at Summit, Greenland. Aerosol mass size distributions as well as daily average concentrations of several anionic and cationic species were measured. Dry deposition velocities for SO42− were estimated using surrogate surfaces (symmetric airfoils) as well as impactor data. Real-time concentrations of particles greater than 0.5 μm and greater than 0.01 μm were measured. Snow and fog samples from nearly all of the events occurring during the field season were collected. Filter sampler results indicate that SO42− is the dominant aerosol anion species, with Na+, NH …
Global Perspective Of Nitrate Flux In Ice Cores, Qinzhao Yang, Paul A. Mayewski, Sallie I. Whitlow, Mark S. Twickler, Michael Morrison, R. Talbot, Jack E. Dibb, Ernst Linder
Global Perspective Of Nitrate Flux In Ice Cores, Qinzhao Yang, Paul A. Mayewski, Sallie I. Whitlow, Mark S. Twickler, Michael Morrison, R. Talbot, Jack E. Dibb, Ernst Linder
Earth Sciences
The relationships between the concentration and the flux of chemical species (Cl-, NO3 - , SO42-, Na +, K + , NH4 + , Mg 2+ , Ca 2+) 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 (a = 0.05) related to snow accumulation rate. Of all the chemical series, only nitrate concentration data are normally distributed. Therefore we suggest that nitrate concentration …
1995, Spatial And Temporal Variability Of Late Neogene Equatorial Pacific Carbonate, T. K. Hagelberg, Nicklas G. Pisias, Larry A. Mayer, N. J. Shackleton, Alan C. Mix
1995, Spatial And Temporal Variability Of Late Neogene Equatorial Pacific Carbonate, T. K. Hagelberg, Nicklas G. Pisias, Larry A. Mayer, N. J. Shackleton, Alan C. Mix
Affiliate Scholarship
High-resolution, continuous records of GRAPE wet bulk density (a carbonate proxy) from Ocean Drilling Program Leg 138 provide one the opportunity for a detailed study of eastern equatorial Pacific Ocean carbonate sedimentation during the last 6 m.y. The transect of sites drilled spans both latitude and longitude in the eastern equatorial Pacific from 90° to 110°W and from 5°S to 10°N. Two modes of variability are resolved through the use of Empirical Orthogonal Function (EOF) analysis. In the presence of large tectonic and climatic boundary condition changes over the last 6 m.y., the dominant mode of spatial variability in carbonate …
Paleoceanography Of The Eastern Equatorial Pacific During The Neogene: Synthesis Of Leg 138 Drilling Results, Nicklas G. Pisias, Larry A. Mayer, Alan C. Mix
Paleoceanography Of The Eastern Equatorial Pacific During The Neogene: Synthesis Of Leg 138 Drilling Results, Nicklas G. Pisias, Larry A. Mayer, Alan C. Mix
Affiliate Scholarship
The primary objective of Leg 138 was to provide detailed information about the ocean's response to global climate change during the Neogene. Two north-south transects were drilled (95° and 110°W) within the region of equatorial divergence-driven upwelling (and thus high accumulation rates and resolution) and spanning the major equatorial ocean current boundaries (and thus recording a high-amplitude signal of the response of the sediment to climatically and/or tectonically driven changes in ocean circulation). The Neogene is marked by a number of well-known climatic and tectonic events (the closing of the Isthmus of Panama, the onset of North Atlantic Deep Water …
Seismic Stratigraphy Of The Eastern Equatorial Pacific Ocean: Paleoceanographic Implications, Stephen F. Bloomer, Larry A. Mayer, Ted C. Moore Jr
Seismic Stratigraphy Of The Eastern Equatorial Pacific Ocean: Paleoceanographic Implications, Stephen F. Bloomer, Larry A. Mayer, Ted C. Moore Jr
Affiliate Scholarship
The collection of Leg 138 well-log and shipboard physical-property data, in conjunction with high-resolution seismic profiles, provides an opportunity to understand the paleoceanographic significance of seismic reflectors and to gain insight into the paleoceanographic evolution of the eastern equatorial Pacific Ocean. A series of eight reflectors or reflector packages were traced between two transects connecting five Leg 138 sites. By generating synthetic seismograms at each of these sites and comparing these to the field records, the origin of these seismic reflectors was determined in terms of physical-property variations and other core measurements. In particular, these reflectors were usually associated with …