DE3 is an atmospheric tide with a 3 number of waves propagating eastward on Sunday, stimulated primarily by latent heat releases from the tropics, and is considered one of the most important tidal components of non-migratory tides. As a key dynamic process for the height of the mesosphere-low thermosphere, the DE3 tides are vertically coupled between the lower and upper atmospheres. On the one hand, the climate changeability of DE3 is regulated by the lower atmospheric climate, including el southern oscillation (ENSO), quasi-two-year oscillation (QBO) and Madden-Jullian oscillation (MJO). DE3, on the other hand, propagates upward into the upper atmosphere to drive the longitude four-wave (WN4) structure that produces the ionosphere and the thermal layer. Over the past few decades, the seasonal variation of DE3 tides with different atmospheric parameters such as temperature, wind and density and their altitude-dimensional structure have been extensively studied. In addition to seasonal variations, day-by-day variations on the weather timescale of DE3 are also evident in observations and simulations. However, the current research on the day-to-day variability of DE3 tides is still not in-depth enough. In terms of observations, methods for extracting daily tides are developing, but mainly focus on temperature tides, and there is a relative lack of research on wind field tides. This is mainly due to the error of the relevant measurement and the spatial and temporal coverage. In terms of modeling, while models are a powerful tool in theoretical analysis, verification through observation is still rare. This is also important for assessing the performance of the model and the accuracy of the data processing method.
Figure 1 The daily change of DE3-U with latitude and altitude caused by tidal phase changes. From left to right, january to December, the corresponding year is marked on the left
Figure 2 The tidal phase changes in the equator observations (a) and SD-WACCM-X simulations (b) of approximately 116 km result in month-by-day changes in DE3-U. The red dotted line is the result of the half-year change fitting of the sine function
The research results were published in the international academic journals JGR-Atmosphere (Zhou Xu, Le Xin'an*, Yu You, Hu Lianhuan. Day-to-day variability of the MLT DE3 using joint analysis on observations from TIDI-TIMED and a meteor radar meridian chain [J]. Journal of Geophysical Research: Atmospheres, 2022, 127(13): e2021JD035794. DOI:10.1029/2021JD035794）。 The results have been funded by the Chinese Academy of Sciences Pilot Project (XDB41000000), the Chinese Academy of Sciences Youth Team Basic Research Project (YSBR-018), the Meridian Project, and the China Postdoctoral Fund (292174).
Editor: Chen Feifei
Proofreader: Zhou Xingxing Liu Qi county