Pollen, Oxygen Isotope Content and Seasonality in an Ice Core from the Penny Ice Cap, Baffin Island

The results of pollen analyses of 12 ice core samples, covering an eight-year period from 1972 through 1979 from the divide of the Penny Ice Cap, Baffin Island, are reported. The pollen spectra are dominated by long distance transported pollen, especially the conifers Picea and Pinus. Alnus pollen is generally rare. In contrast, pollen spectra from both modern polsters and fossil peat sections in the same area are both characterized by local pollen types. Pollen influx values range from 2 to 8 grains/cm²/yr. Where the sampling intervals happened to coincide with established seasonal intervals (as interpreted from later oxygen isotope studies) the pollen spectra showed seasonal characteristics. This occurred in five out of the twelve samples. Comparison of these data is made with data from Devon Island Ice Cap. Such information may be useful in reconstructing paleoclimates.Key words: pollen, ice cap, Baffin, isotope, paleoclimatesMots clés: pollen, cap glacial, Baffin, isotope, paleoclimat

John Hainsworth Mercer, 1922-1987

From 1951 until 1954, Mercer studied at McGill University. His Ph.D. thesis, ... was based on field work carried out in the vicinity of the Grinnell and Terra Nivea ice caps on southern Baffin Island. ... Mercer was highly motivated by field work and literally thrived on it. Typically, and often to the chagrin of at least one of his contemporaries, Mercer did not unnecessarily burden himself (or others) with loads of data. Many of his papers seemed to be largely based on his unusual synthesizing and perceptive powers, supported, where necessary, by a few, but key, radioisotope dates. Mercer was not a compulsive lecturer - in fact, he shunned such "duties" - but for those of us at the institute as graduate students (of which G.H. was one) Mercer was frequently a source of both private inspiration and considerable amusement. An important paper in 1968 set in motion his and others' ideas on the dynamics of "marine ice sheets" (Mercer, 1968). ... His realistic thinking through the ice sheet dynamics scenarios and the associated sea level changes inspired the numerical modellers to dedicate their paper to him. ... The results of his field work are of great importance in synthesizing the spatial variations of global climate change, which was one of the underlying themes of Mercer's research. ... His stimulating presence will be widely missed, especially by those at the Byrd Polar Research Center in Columbus, Ohio

Snow accumulation time series and their climatic interpretation

EXTRACT (SEE PDF FOR FULL ABSTRACT): Several snow accumulation time series derived from ice cores and extending over 3 to 5 centuries are examined for spatial and temporal climatic information. ... A significant observation is the widespread depression of net snow accumulation during the latter part of the "Little Ice Age". This initially suggests sea surface temperatures were significantly depressed during the same period. However, prior to this, the available core records indicate generally higher than average precipitation rates. This also implies that influences such as shifted storm tracks or a dustier atmosphere may have been involved. Without additional spatial data coverage, these observations should properly be studied using a coupled (global) ocean/atmosphere GCM

Changes in mid-troposphere snow accumulation on Mt. Logan, Yukon, over the last three centuries

EXTRACT (SEE PDF FOR FULL ABSTRACT): A net snow accumulation time series is presented. It is derived from a 102.5 m ice core retrieved from Mt. Logan at an altitude of 5340 m a.s.l. Annual increments are identified using stable isotopes, trace chemistry, and beta activity. ... The resulting time series of nearly 300 years seems to indicate a lower mean accumulation from AD 1700 to the mid-19th century than after that time. The last 100 years of the series correlates significantly with certain instrumental station records at mid-northern latitudes

Evidence from the Pacific Northwest for solar modulation of climate and of northern ecosystems

EXTRACT (SEE PDF FOR FULL ABSTRACT): The 250-year net annual snow accumulation, or mass balance, time series derived from the Mt. Logan (Yukon) ice core has been spectrally analyzed and is found to contain a nominal 11-year waveform. The stable isotope time series contains a significant amount of power between 9 and 13 years, although this record is evidently not a straightforward proxy for air temperatures. The signal in the mass balance time series exhibits a close relationship with the sunspot cycle waveform and is, therefore, assumed to be related to it. Waveforms showing a high correlation with the solar cycle are found in other climate data in the region. ... Taken collectively, the data point to a link between solar variability, atmospheric variability, climate, and selected ecological dynamics in the Pacific Northwest, but other data, not presented, indicate these relationships may hold elsewhere. So far, the evidence is empirical; complete details of the physical mechanisms involved have yet to be synthesized in a satisfactory way