Abstract: Matched-field processors can suffer degradation in dynamic ocean environments due to mismatch between data and replica vectors.One measure of such degradation is the temporal correlation length of the data vectors. Temporal correlation length for 400 Hz narrow band signals has been extracted from the acoustic data received by a vertical hydrophone array of the 2001 Asian Seas International Acoustics Experiment (ASIAEX).With nonlinear internal waves entering the acoustic signal propagation path,signal temporal correlation length dropped fast.In addition,sound field is simulated from the temperature data of three temperature sensor arrays on the propagation path with a two-dimensional advective frozen-ocean model.Signal temporal correlation length of the simulation for 400 Hz signals can be compared with the experimental data qualitatively.It is concluded that,in this environment,nonlinear internal waves propagating in the acoustic path will shorten the signal temporal correlation length.