Abstract: Ulanbuh Desert is the main source of aeolian sand blown into the Upper Yellow River. Previous studies on the aeolian sand focused on the amount entering into the Yellow River and rarely involved variation of the influence factors that determine the amount variation of aeolian sand. Channel bank boundary, land use along the desert, and wind conditions and sandstorm frequency since 1950s have been analyzed with the long-term variation characteristics. Results showed that:The left levee with 33.086 km long has been built since 1990s, which redefined the left scope of the river. There are a 4.05-km-long movable dune adjacent to the river that has decreased greatly in comparison to that in 1980s. The semi-fixed dunes have a long distance to the river, where villages, farmlands, and land developed between the river and semi-fixed dunes. Meanwhile, the mean annual wind speed in the desert region has reduced by 1.0-1.3 m·s^-1 since 1950s, and the maximum annual wind speed has also reduced by 6.0-10.0 m s^-1 since early 1990s. Change of land use and the construction of the embankment somewhat restrain the amount of aeolian sand blown into the Yellow River. Variation of the meteorological conditions leads to the decrease of the frequency of sandstorms so as to reduce the aeolian sand amount accordingly. Moreover, the period of the meteorological conditions influencing aeolian sand is closely related to the cycle of climate change.

Key words: Ulanbuh Desert, aeolian sand, land use, meteorological condition, Upper Yellow River