NUMERICAL-SIMULATION OF REMOTE ACOUSTIC SENSING OF OCEAN TEMPERATURE IN THE FRAM STRAIT ENVIRONMENT

An important part of the general problem of the Arctic climate change is the monitoring of the Fram Strait, which lies between Greenland and Spitsbergen. For this reason it is reasonable to apply acoustic metho ds which are proven to be effective in acoustic ocean thermometry, aco ustic tomography, etc. Knowledge of the main peculiarities of sound si gnal propagation in this region is needed to estimate the feasibility of applying remote acoustic methods. To this end computer simulation o f sound signal propagation in the Fram Strait environment was performe d, based on oceanographic data obtained by the R/V POLARSTERN expediti on. The presence of stable eigenrays in Fram Strait environmental cond itions is demonstrated, typical values of acoustic signal travel time fluctuations due to environmental variations are determined, and the t emperature effect on the signal travel time variation is considered. S ensitivity estimates for measurement of the average ocean temperature across Fram Strait is considered in two approaches: by calculating tra vel time changes along selected stable eigenrays, and by determining t he cumulative sum of the whole envelope of the signals passed along wa ter-borne paths. (C) 1998 Acoustical Society of America.. [S0001-4966( 98)05808-1]