An evident signature of a least studied quasi-90-day oscillation is found in the winds and tides in the MLT from an equatorial station, São João do Cariri (7.4°S, 36.5°W). The oscillation is found to appear mainly in certain intervals with small but appreciable seasonal (fourth harmonic of annual oscillation) contribution. The maximum amplitude of the oscillation is found to be around 10 m/s in the zonal wind. The enhancement peak of the oscillation exhibits downward movement indicating a plausible role of upward moving waves/tides in carrying its imprint from below to the MLT. Similar oscillation feature in the tropospheric zonal wind and ozone may imply its lower atmospheric origin as a component of the intraseasonal oscillation (ISO) that moves upward by modulating the tides. Subsequently, the propagating tides (mainly semidiurnal) are enhanced by the ozone in the stratosphere through absorption of solar UV radiation and finally manifest the oscillation in the MLT. Consistency of the present findings with the past investigations are observed in some aspects of the oscillation, whereas existing mismatches in others are believed to be due to geophysical variability depending on space and time among various locations on the globe.

在赤道站SãoJoãodo Cariri（7.4°S，36.5°W）的MLT的风和潮中发现了最少研究的准90天振荡的明显特征。发现振荡主要出现在特定的时间间隔内，具有较小但可观的季节性（年度振荡的四次谐波）影响。发现在纬向风中，振荡的最大幅度约为10 m / s。振荡的增强峰表现出向下运动，表明向上移动的波/潮汐在将其印迹从下方传递到MLT方面似乎具有合理的作用。对流层带风和臭氧中类似的振荡特征可能暗示其较低的大气起源是季节内振荡（ISO）的一部分，该季节内振荡通过调节潮汐而向上移动。随后，平流层中的臭氧通过吸收太阳紫外线辐射来增强传播的潮汐（主要是半日潮），并最终在MLT中表现出振荡。在振荡的某些方面观察到了本研究结果与过去研究的一致性，而其他方面存在的不匹配被认为是由于地球物理变异性所致，而地球物理变异性取决于地球上各个位置之间的空间和时间。