In seasonal variation…
Monsoonal wind transports the water into or out of the Gulf, which changes the water level and flow pattern in the Gulf.
![](https://repun-app.fish.hokudai.ac.jp/pluginfile.php/2124/mod_label/intro/onishi%20fig7.png)
In interannual variation…
Positive Dipole Mode of Indian Ocean
prompts strong SW monsoon over the Gulf, which makes huge outflow and promotes
estuarine type water exchange through the Gulf mouth.
![](https://repun-app.fish.hokudai.ac.jp/pluginfile.php/2124/mod_label/intro/onishi%20fig8.png)