We investigated the possible widening of the tropical belt along with the probable drivers and impacts based on high-accuracy, high-resolution GNSS RO data (2001–2020). The results show that the tropical belt has significant expansion in the Northern Hemisphere, while the Southern Hemisphere has no significant expansion.

In this paper, the receiver differential code bias (DCB) of BDS (BeiDou Navigation Satellite System) is estimated as the changing parameter within 1 d with epoch-by-epoch estimates. The intraday variability of receiver DCB is analyzed from 30 d of Multi-GNSS Experiment observations. In particular, the intraday stability of receiver DCB for the BDS-3 and BDS-2 observations is compared. The result shows that the intraday stability of BDS-3 receiver DCB is better than that of BDS-2 receiver DCB.

Atmospheric drag due to mass density distribution, particularly during storm-time, is of great importance for low Earth orbit precise orbit determination, and for the understanding of magnetosphere–ionosphere–thermosphere phenomena. In this paper, we investigate solar cycle, seasonal, and hemispheric asymmetry dependencies of thermospheric mass density disturbances due to magnetospheric forcing, from 10-year (2003–2013) continuous time series of GRACE estimates.

A significant warming in the troposphere and cooling in the stratosphere are found in satellite measurements (2002–2017). The newest ERA5 data are first used for analyzing temperature and ozone trends in the UTLS and show the best quality compared to other reanalyses. According to model simulations, the temperature increase in the troposphere and ozone decrease in the NH stratosphere are mainly connected to a surface warming of the ocean and subsequent changes in atmospheric circulation.