Feasibility of Coupled Pattern Reconstruction Technique in the Detection of Internal Waves

The main focus of this paper is to study the feasibility of coupled pattern reconstruction technique (CPR) developed by Nardelli and Santoleri (2004) in detecting the internal waves at three locations in the north Indian Ocean. In all the cases, the first two modes, viz. Mode 0 and Mode 1, explained most of the co-variability between these two parameters at all the three locations (91% in the northern Bay of Bengal and 97% in the coastal waters). Moreover, the coefficients that relate the amplitudes of temperature and steric height for the first two modes follow a linear relationship, satisfying the conditions of the CPR. The temporal variations of these two modes are found to be within the bands of tidal periodicity. The CPR technique was able to reconstruct the synoptic scale variation in the temperature at different depths with a reasonable degree of accuracy. This technique was able to capture the variability within the bands of tidal periodicity (6-24 hrs) as evident from the oscillations in the thermocline region. Even though there are small differences in the amplitude of oscillations, very good agreement is observed and simulated phase of these oscillations, which is important in the study of internal waves. The analysis supported that the CPR technique is suitable for the simulation of low frequency internal waves provided the surface fields are available at this time intervals.