There is great scientific interest in extending atmospheric models, such as the Met Office’s Unified Model, upwards to include the upper atmosphere. Atmospheric tides are an important driver of circulation at these greater heights. This study provides a first in-depth analysis of the migrating and non-migrating components of these tides, examining important tidal properties. Our results show that the ExUM produces a rich spectrum of spatial components, with significant non-migrating components.

There is great scientific interest in extending atmospheric models upwards to include the upper atmosphere. The Met Office’s Unified Model has recently been successfully extended to include this region. Atmospheric tides are an important driver of atmospheric motion at these greater heights. This paper provides a first comparison of winds and tides produced by the new extended model with meteor radar observations, comparing key tidal properties and discussing their similarities and differences.

We provide an analysis of processing setting impacts on tropospheric gradients estimated from GNSS observation processing. These tropospheric gradients are related to water vapour distribution in the troposphere and therefore can be helpful in meteorological applications.

A comparison between the GNSS tomography technique and WRFDA in retrieving wet refractivity (WR) is conducted in HK during a wet period and a dry period. The results show that both of them can retrieve good WR. In most of the cases, the WRFDA output outperforms the tomographic WR, but the tomographic WR is better than the WRFDA output in the lower troposphere in the dry period. By assimilating better tomographic WR in the lower troposphere into the WRFDA, we slightly improve the retrieved WR.