Kevin K. Ferland

Greenland ice core “signal” characteristics: An expanded view of climate change

The last millenium of Earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity. The authors have analyzed the major ions contained in the Greenland Ice Sheet Project 2 (GISP 2) ice core from the present to {approximately}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. They 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 (signals) were {open_quotes}stationary{close_quotes} and by utilizing evolutionary spectral analysis, they were able to reveal periodic processes in the climate system which change in frequency, {open_quotes}turn on,{close_quotes} and {open_quotes}turn off{close_quotes} with other climate transitions such as that between the little ice age and the medieval warm period. 42 refs., 4 figs., 2 tabs.

Ice-core sulfate from three northern hemisphere sites: Source and temperature forcing implications

Abstract Comparison of ice-core nss sulfate records (two sites in Greenland and one in the North Pacific) with temperature change records for the regions including these core sites provides further confirmation that change in the concentration of anthropogenic sulfate has had a significant effect on regional temperature during at least the period ∼ ad 1940–1970 over at least the Atlantic portion of the Arctic. Using the ad 1880–1985 portion of our ice-core records as an analog, we provide a test of the potential temperature depression caused by non-seasalt (nss) sulfate aerosols over Greenland during the period ∼ ad 700–1900 concluding that the anthropogenic era is unique by comparison. Statistical examination of this record allows a determination of the relative contributions of volcanic vs biogenic source nss sulfate during this period plus a characterization of the variability in these two sources.

Extending Two Classic Proofs of the Pythagorean Theorem to the Law of Cosines

Summary Two well-known proofs of the Pythagorean theorem are generalized to prove the law of cosines in a geometrically elegant way by computing areas.

Greenland Ice Core Greenland Ice Core "Signal" Characteristics: An Expanded View of Climate Change

The last millenium of Earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity. The authors have analyzed the major ions contained in the Greenland Ice Sheet Project 2 (GISP 2) ice core from the present to {approximately}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. They 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 (signals) were {open_quotes}stationary{close_quotes} and by utilizing evolutionary spectral analysis, they were able to reveal periodic processes in the climate system which change in frequency, {open_quotes}turn on,{close_quotes} and {open_quotes}turn off{close_quotes} with other climate transitions such as that between the little ice age and the medieval warm period. 42 refs., 4 figs., 2 tabs.

Greenland ice core {open_quotes}signal{close_quotes} characteristics: An expanded view of climate change

The last millenium of Earth history is of particular interest because it documents the environmental complexities of both natural variability and anthropogenic activity. The authors have analyzed the major ions contained in the Greenland Ice Sheet Project 2 (GISP 2) ice core from the present to {approximately}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. They 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 (signals) were {open_quotes}stationary{close_quotes} and by utilizing evolutionary spectral analysis, they were able to reveal periodic processes in the climate system which change in frequency, {open_quotes}turn on,{close_quotes} and {open_quotes}turn off{close_quotes} with other climate transitions such as that between the little ice age and the medieval warm period. 42 refs., 4 figs., 2 tabs.