CAJ | 학술논문

首次将经验模态分解方法引入湍流稳定性分析，与传统的线性和滑动平均去势方法进行了比较，发现经验模态分解方法的去势效果最好。基于“南海平台通量观测计划”（FOPSCS）近两年的连续通量观测数据，得到了22476个摩擦速度的估算值，结果表明，当风速小于5 m/s 时，拖曳系数随风速增大而减小，而风速大于5 m/s 时，拖曳系数随风速增大而增大，两种情形分别反映了黏性表皮摩擦和波浪引起的形状阻力对海面风应力的贡献。同时发现短风区情形的拖曳系数大于长风区情形，说明波浪成长状态会对海-气界面动量交换产生影响。
수차장경험모태분해방법인입단류은정성분석，여전통적선성화활동평균거세방법진행료비교，발현경험모태분해방법적거세효과최호。기우“남해평태통량관측계화”（FOPSCS）근량년적련속통량관측수거，득도료22476개마찰속도적고산치，결과표명，당풍속소우5 m/s 시，타예계수수풍속증대이감소，이풍속대우5 m/s 시，타예계수수풍속증대이증대，량충정형분별반영료점성표피마찰화파랑인기적형상조력대해면풍응력적공헌。동시발현단풍구정형적타예계수대우장풍구정형，설명파랑성장상태회대해-기계면동량교환산생영향。
The empirical mode decomposition (EMD)method is introduced to analyze the stability of turbulence for the first time and is compared with the traditional detrending methods,like linear detrending(LDT)and running mean filtering (RMF).The results show that EMD is the most reliable method to obtain momentum flux at the air-sea surface.Based on about two years of data from Flux Observation on Platform in South China Sea (FOP-SCS)project,22 476 friction velocities were obtained.It was found that when the wind speed is less than 5 m/s, the drag coefficient decreases with the increase of wind speed;whereas,the trend is opposite when wind speed is greater than 5 m/s.These two different cases reflect the contribution to the wind stress from the roughness gener-ated by viscous boundary-layer and wave-induced form drag,respectively.Further analysis shows that the drag co-efficient with limited fetch condition is larger than that with unlimited fetch,which revealed the wave age can also influence the momentum exchange at the air-sea surface.