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Beryllium 7 And Lead 210 In The Western Hemisphere Arctic Atmosphere: Observations From Three Recent Aircraft-Based Sampling Programs, Jack E. Dibb, R. Talbot, G L. Gregory
Beryllium 7 And Lead 210 In The Western Hemisphere Arctic Atmosphere: Observations From Three Recent Aircraft-Based Sampling Programs, Jack E. Dibb, R. Talbot, G L. Gregory
Earth Sciences
Concentrations of the natural radionuclides 7Be and 210Pb were determined in aerosol samples collected in the western hemisphere Arctic during the recent NOAA Arctic Gas and Aerosol Sampling Program (AGASP 3) and NASA Global Tropospheric Experiment/Arctic Boundary Layer Expeditions (GTE/ABLE 3A and ABLE 3B) missions. Beryllium 7 showed a free tropospheric concentration maximum between 4 and 5 km in the summer of 1990. Previous 7Be data obtained in the late 1950s and early 1960s also indicated a similar vertical distribution of 7Be near 70°N. Injection of stratospheric air through tropopause folds associated with the Arctic jet …
The Accumulation Of 210pb At Summit, Greenland Since 1855, Jack E. Dibb
The Accumulation Of 210pb At Summit, Greenland Since 1855, Jack E. Dibb
Earth Sciences
The decay corrected activity of 210Pb at the time of deposition shows considerable short term variability, but no clear seasonal or annual periodicity. 210Pb activity in surface snow at this site has averaged 0.7 pCi kg-1 since 1927, but the period 1915-1927 is characterized by a steady decline from higher levels. The average annual accumulation of 210Pb has markedly declined since at least 1870. Similar observation at Dye 3 suggest that 210Pb accumulation has decreased throughout this century over much of the Greenland Ice Sheet. If the records of 210Pb in the firn of the Greenland Ice Sheet are mainly …