Ph.D. Columbia (1965)
303 Fronczak Hall
Lab: 340 Fronczak Hall, (716) 645-6252
Ph.D. -- Columbia University (1965)
M.S. -- Technion, Israel (1962)
B.S. -- Technion, Israel (1960)
My research efforts in recent years have mainly been involved in getting information on past climates and climate change. As a principle investigator in the National Science Foundation's Greenland Ice Sheet Project 2 (GISP2) initiative, I developed laser-light scattering (LLS) techniques to measure the dust profile along the length of the 3000plus-meters-long GISP2 ice core that was retrieved from central Greenland. Since the dust in the ice is believed to be representative of past atmospheric dust burdens, our measurements reflect how past atmospheric dust burdens changed over the past 100,000-plus years. This information is of critical importance in climate modeling since atmospheric dust can absorb and scatter solar energy, and can thus modify the earth's albedo. Since it is known that dust concentration in the core varies seasonally with maxima occurring every spring/summer, our work has been of critical importance in dating the GISP2 ice core. In addition, our work is yielding important information on violent dust storms that seem to have been prevalent during cold glacial times. Also, we observed that the dust concentration along the ice core was modulated with 11-, 20-, 90-, and 200-year periods, which we attribute to the solar cycle. These modulations occur throughout the core, and we observe them all the way back to 100,000 years BP. We have suggested that the dust modulations are a consequence of solar modulation of the terrestrial cosmic ray flux, which can influence cloud cover. FIG. 1 Dust profile of GISP2 ice core observed using laser- light scattering (LLS) from ice. For comparison, we also show the oxygen isotope profile. Colder periods, corresponding to more negative oxygen isotope ratios, go hand-in-hand with periods of higher dust concentration, which is consistent with the idea that the weather was significantly stormier during the colder periods of the last ice age.