Geoscience Reference
In-Depth Information
the U.S Arctic Submarine Lab, during which some time is set aside for the collec-
tion of unclassified scientific data (e.g., hydrographic and ice thickness data) during
otherwise classified missions.
Information on surface air pressure, air temperature, and ice drift in the central
Arctic Ocean was greatly augmented by the inauguration in 1979 of the Arctic Ocean
Buoy Program by the University of Washington, Seattle. In 1991, this became the
International Arctic Buoy Program (IABP) and involves cooperation between many
nations. Initially, around twenty buoys were deployed, mainly from airdrops; but
in the 1990s, the number rose to more than thirty operating at any time. Data are
relayed via satellite in near-real time to the Global Telecommunications System.
Newer technologies include drifting buoys that can measure changes in ice thick-
ness (mass balance buoys) and that carry thermistor strings.
Oceanographic data from the IAPB and submarines are complemented by pro-
grams maintaining arrays of upward looking moored sonar (to obtain ice draft),
moored buoys recording temperature and salinity and other variables across the
major Arctic straits, and CTD casts (conductivity, temperature, depth). An exam-
ple of one of these programs is Arctic-Subarctic Ocean Flux Study (ASOF), an
international effort with the objective of measuring and modeling variability in
the fluxes of mass, heat, and salt between the Arctic Ocean and the subpolar seas.
ASOF itself grew from the VEINS program (Variability of Exchanges in the
Northern Seas).
The first deep ice core from the Greenland Ice Sheet was recovered in 1966
from a 1387-meter hole drilled to bedrock at Camp Century (71.2°N, 61.1°W,
1,885 m) (Dansgaard et al.,
1971
). For many years this provided the primary record
of glacial and post-glacial climate through analysis of isotopic composition, trapped
air bubbles, and other paleoclimate information. Additional cores were obtained
from Greenland and from ice caps in the Canadian Arctic, but major advances in
paleoclimate research followed the Greenland Ice Sheet Project 2 (GISP 2) and
the European Greenland Ice Core Project (GRIP). Holes drilled between 1989 and
1993 provided more than 3,000 meters of ice core near Summit (72.6°N, 34.6°W)
(Hammer et al.,
1997
). In 1999, U.S. and European agencies installed a new year-
round atmospheric observatory at Summit, complementing a chain of automatic
weather stations installed in the 1990s around the ice sheet (Steffen, Box, and
Abdalati,
1996
) and still maintained.
The breakup of the Soviet Union in 1991 dealt a blow to the Arctic research com-
munity. Through the 1970s and 1980s, there was continued growth in the network of
surface stations in the Soviet Arctic providing information on temperature, precip-
itation, river discharge, and upper-air conditions. But following the breakup, eco-
nomic realities forced the closure of many sites, as well as termination of the North
Pole drifting station program (which, as discussed, has been reinitiated). Routine
aircraft ice reconnaissance flights were also discontinued. In turn, cost-cutting in
Canada during the 1990s led to the loss of stations and the replacement of others
by automatic systems. Generally speaking, the most complete database of surface
observations in the Arctic is for the 1960-1990 period.
