AIDJEX Revisited: A Look Back at the U.S.-Canadian Arctic Ice Dynamics Joint Experiment 1970-78

THE ARCTIC ICE DYNAMICS JOINT EXPERIMENT (AIDJEX) was an American-Canadian project to develop a comprehensive model of sea ice cover under the combined influences of the atmosphere and the ocean. From sea ice modeling studies in the 1950s and early 1960s, it had become clear that the "missing link" in resolving the momentum equation was the flow law for sea ice, that is, the law describing internal ice stress and its spatial propagation (Doronoin and Kheisin, 1975). The central idea of AIDJEX was that a realistic formulation of this law would eventually permit the construction of a sea ice model that could be built into the global climate models being developed at that time. The core observational program produced data on the geographical coordinates of data buoys and manned camps and the barometric pressure and air temperature at these locations. At the manned camps, vertical arrays of anemometers and thermometers were used to deduce the horizontal stress exerted by the wind. Similarly, arrays of current meters below the ice yielded data for the water stress. The dynamic tilt of the sea surface was calculated from deep profiles of ocean temperature and salinity. Routine threehourly weather observations were taken in support of flight operations (for a full description of the observational program, see the 1975 Operations Manual). This program was designed to measure the external forcing on the ice and its motion and deformation, which were required to realize the scheme outlined in Figure 1. In addition to the core program of AIDJEX, a number of special geophysical studies were conducted that used the existence of a manned station array as a logistical base of opportunity. These studies are also described in the Operations Manual. At the very beginning, the funding agencies made it clear that AIDJEX was a finite-duration study, and that we could not expect to see it "institutionalized" upon its completion. Many post-AIDJEX proposals for continued work were declined, and it took several years for the Polar Science Center at the University of Washington to emerge as a "Son-of-AIDJEX" research group consisting of several principal investigators pursuing individual topics. However, our convincing success in obtaining data on ice deformation and air stress by means of buoys enabled us to secure continued funding, which ultimately led to the International Arctic Buoy Program (see below).