The Study Of The Dynamic Effects Of Sea Spray At Air-Sea Interface

Sea spray,or ocean spray,consists of small water droplets,forms through a number of different processes at the air-ocean interface,the region where atmosphere and ocean meet.It is known to play an important role in momentum,heat,and moisture transfer between the ocean and atmosphere.Hurricanes may need the additional heat fluxes provided by spray in order to reach observed intensities.Therefore,knowledge of the air-sea interaction of sea spray is of primary importance for severe weather forecasts,risk assessments,wave and surge forecasts,marine engineering and transport safety.Based on the previous research and observation,the generation mechanism of sea spray is discussed in this paper,and the new sea spray generation function(SSGF),described by windsea Reynolds number,which depends on wind and wave,will be used to integrate into the spray momentum flux formula to calculate the spray momentum.Based on these,we derived the new formulas of spray stress and drag coefficient at high wind speed.The results of our new revised formulas show that wave status does have significant effects on the spray stress and sea surface drag coefficient.Through our analysis,wave age is another important parameter to describe the wave state dependence of the drag coefficient which decrease as the wave age increase.This paper also describes the results from simulations of sea spray drops over the ocean.Firstly,we summarized the result of previous studies about the spray motion and microphysics.Then,we used large eddy simulation to perform the air flow over the sea surface while simultaneously tracking the trajectories of Lagrangian point-particle elements designed to represent spray particles in air.At last,we discussed the particle momentum relaxation time,the suspension time,the velocity of particles and the wind speed.This simplified model shows that the contribution of droplet particles to the air-sea momentum transport can not be ignored.The existence of droplets changed the contact state of the air-sea interface.Especially at high wind speed,in which the droplet number and thickness of mixed layer both reached a certain magnitude,which will change the friction state of the ocean and atmosphere.