The investigators on the present collaborative project are all part of an ongoing international effort focusing on these questions in the Summit region of the Greenland ice sheet, where the GISP2 and GRIP ice cores have recently been recovered and analyzed in unprecedented detail for a wide range of chemical constituents. Through a combination of laboratory experiments, model development and collection of field data for several summer seasons, we have gained considerable insight into air-snow relationships. For some chemical species we can now use concentrations measured in the summer layer of the snowpack to estimate mean atmospheric concentrations that agree with those measured during the summer season to better than a factor of two. Photo A primary goal of the winter-over program is to collect and analyze air samples during the winter months for many chemical species. University of Arizona scientists installed a detector to measure hydrogen peroxide levels, and NOAA scientists sent an ozone monitor to the site.
Air is drawn in from outside into the detectors, where it is analyzed immediately.
Twice daily the data are downloaded from the detector to the computers shown in the photo. Brent Matson Photo Although located in an extremely remote environment, human activity at Summit produces enough air pollution to affect our chemical analysis of hydrogen peroxide in the air. Locating the air intake line well up a tower helps insure more pristine air is collected and analyzed. The line is wrapped in black foam and heated with resistor wire to prevent condensation of moisture in the tubing. Such condensation results in significant signal loss.