Figure 5: Simulated dynamic height anomalies in the Indonesian Seas and the surrounding regions for (a) September 1995 and (b) May 1997. Unit is dyn.cm.
The meridional pressure gradient associated with the positive dynamic height anomaly off Mindanao and the negative value in the archipelago tends to enhance the throughflow transport since the Coriolis term almost vanish near the equator. At the exit to the Indian Ocean between the coasts of Java and Australia, on the other hand, the large throughflow transport in geostrophic balance is related to the positive anomalies near Australian coast and the negative anomalies in the northern part of the region. Those two conditions at both sides of the archipelago seem to be important to regulate the throughflow transport in the present model.
In september 1995, for example when the transport reaches to the maximum of IR case, the meridional pressure gradients at both sides of the archipelago tend to strengthen the throughflow (Figure 5a). The opposite conditions occur in May 1997 during the period of the minimum throughflow (Figure 5b). It is interesting to show that there is the time when the two conditions affect the throughflow transport in the opposite way. Figure 6 shows the dynamic height distribution near the Indonesian Seas in December 1995, when the interannual anomaly of the transport is almost zero (see Fig. 3). Although the strong meridional pressure gradient at the Pacific side associated with the positive anomaly off Mindanao Island tries to develop the strong throughflow, the positive anomaly near Java Island creates the favorable condition for weak throughflow. It is important to have appropriate conditions at both sides of the archipelago to generate the variation of the net throughflow transport.
