Jack joined the Glacier Research Group (and presently the Earth Systems Research Center) in 1988, just in time to join the GISP2 deep ice coring effort which was lead by UNH. This opportunity launched an ongoing research focus on air/snow exchange processes, both in Greenland and Antarctica. Over the years dozens of collaborators have been involved. An overarching goal of these investigations is to improve understanding of past atmospheric composition and chemistry from ice core records. In 1998 these studies discovered that extremely active photochemical processing occurs in, and just above, sunlit snow; since that time an additional focus has been to understand how "snow photochemistry" may impact the overlying atmosphere. Current projects at Summit, Greenland are specifically investigating the impact of snow emissions on coupled NOx/HOx and halogen chemistry as part of two International Polar Year (IPY) experiments, AICI and POLARCAT.
Since 1991 Jack has also investigated tropospheric chemistry on regional and larger scales through participation in a serious of airborne campaigns, primarily with Bob Talbot and the NASA Tropospheric Chemistry program. Most recently he flew on the NASA DC-8 in the Atlantic ITCZ, studying the interaction of atmospheric composition and cirrus cloud properties as part of the TC4-Costa Rica campaign. The next DC-8 campaign (named ARCTAS) will target the Arctic in spring and summer, 2008. ARCTAS is also a component of the international IPY/IGAC POLARCAT experiment. A typical NASA campaign science team includes roughly 100 scientists and technicians, coordinated international campaigns involve many additional collaborators.
In all of these investigations Jack contributes measurements of radionuclide tracers and soluble ionic species (gaseous acids and aerosol-associated). The group has also developed a novel technique to quantify water soluble organic carbon in the atmosphere (gas and particulate phases) that has been used for experiments in New Hampshire, Colorado, Greenland, and Houston (with Rob Griffin, Mike Bergin, Jamie Schauer, and several graduate students).
The radionuclide counting lab has also allowed Jack to collaborate on projects investigating sediment dynamics (locally and as far away as New Zealand), and the evolution of geothermal fluids from vents on the East Pacific Rise (with Karen von Damm, Julie Bryce, and their students).
Kenagy, H. S., Sparks, T. L., Ebben, C. J., Wooldrige, P. J., Lopez‐Hilfiker, F. D., Lee, B. H., . . . Cohen, R. C. (2018). NOx Lifetime and NOy Partitioning During WINTER. Journal of Geophysical Research: Atmospheres, 123(17), 9813-9827. doi:10.1029/2018jd028736