The behavior of Graviy wave during the unusual QBO structure in 2015/2016

We explored the gravity wave behavior and its role for the unusual QBO structure in 2015/2016 by analyzing the data of U.S. radiosonde with high vertical resolution over four equatorial stations from 1998 to 2017. The result implies that the gravity wave behavior should play an important role during the QBOW phase interrupted around 22 km in 2015/2016 winter. While the role of gravity wave was not as important as Kelvin waves during the prolonged and upward propagating westerly zonal wind around 27 km. The enhanced gravity wave may be generated by the instability of the stratospheric atmosphere rather than the tropospheric convection because the convection is weak during the unusual QBO structure over the four equatorial stations.