John L. Speisberger
Dept. of Meteorol. and the Appl. Res. Lab., 512 Walker Bldg., Penn State Univ., University Park, PA 16802
Dan Frye
Woods Hole Oceanogr. Inst., Woods Hole, MA 02543
Harley Hurlburt Joe McCaffrey
Naval Res. Lab., Stennis Space Center, MS 39529
Mark Johnson
Univ. of Alaska, Fairbanks, AK 99701
James O'Brien
Florida State Univ., Tallahassee, FL 32306
Successful feasibility experiments for mapping global ocean warming and climate variability with sound have been conducted since 1983 [J. L. Spiesberger et al., J. Acoust. Soc. Am. 92, 384--396 (1992)]. The GAMOT group is developing two new high-technology instruments for making these same measurements in near-real time at one-eighth the cost of our previous measurements taken from sources and receivers connected to shore with cables. One instrument is a surface suspended acoustic receiver (SSAR), which dangles a hydrophone array beneath a freely drifting surface unit. The other instrument is a subsurface autonomous mooring equipped with an acoustic source and a new telemetry scheme for removing travel time changes due to mooring wander in real time. Climatic temperature variability from past and present experiments is studied with state-of-the-art ocean models. A program update will be presented. [Work is supported by the Advanced Research Projects Agency.]