The Role Of The Wave-induced Mixing In An Ocean Circulation Model

A wave-circulation coupled model was incorporated by the MASNUM wave model and the Princeton Ocean Model (POM) base on the non-broken wave induced mixing theory. While do coupling, the wave-number spectrum was calculated first, and then was the wave-induced mixing coefficient (Bv). After that, the Bv was introduced to the circulation model, and the wave-circulation coupled model was then constructed.The wave-circulation coupled model was validated by the comparison of simulated ocean temperature to Levitus data and the objective analysis of simulated ocean current. Then, eight couple-model experiments and two wave-model experiments were designed regarding to three questions raised by our research interest.The first two couple-model experiments were constructed to compare the results of inputting different time-scaled Bv:daily and monthly. And the results showed that the experiment inputted by monthly averaged Bv could somewhat overestimate the role of wave-induced mixing, and it was particularly evident in summer. Then, the simulated ocean temperature over the northwest Pacific in July was chosen to analyze the causes to result in the discrepancy.Second, two wave-model experiments were designed to calculate the all-wavelength Bv, and the separated less than 300m-wavelength Bv(short-wave Bv) and longer than 300m-wavelength Bv(long-wave Bv). Then, the couple-model experiments were renewedly done using the above acquired Bv respectively, and the non-Bv experiment was also done at the same time. Shown by the simulated ocean temperature, the long-wave Bv could mainly influence the upper ocean mixing of 35m-100m.Finally, the roles of wave induced mixing in the thermohaline equation and momentum equation were examined. The separately consideration of wave induced mixing in the thermohaline equations could cause large errors in the simulation of equatorial current system and the temperature field near the equator. On the other hand, the separately consideration of wave induced mixing in the momentum equations would significantly underestimate the role of wave induced mixing, i.e. the wave induced mixing could not play its role over the most regions.