There are high spatial variabilities in climate from the upstream to the downstream. It is found that the precipitation decreased much in the region between the Lanzhou and Huayuankou gauge, which implies that the reductions of discharge are due, at least in part, to less precipitation. The precipitation decreasing region concentrates in the Loess Plateau, suggesting it is a precipitation "hot spot" of the Yellow River drying up.
The mean air temperature shows increasing trend over the whole basin, and the largest increase regions are the Tibetan Plateau and Qingtongxia-Hetao district. The large increase in minimum temperature in the Tibetan Plateau and Qingtongxia-Hetao district contributes to the mean temperature increase and the reduction of DTR in these regions. The evaporative demand of the atmosphere in eastern Tibetan Plateau and Hetao district shows a significant increasing trend. The Tibetan Plateau and Qingtongxia-Hetao district could be a temperature "hot spot" of the basin drying up.
The Qingtongxia-Hetao IDs show an obvious increasing trend in LAI values, indicating intensive human activities have changed the vegetation condition in that region. The vegetation improvement and water consumption in the Qingtongxia-Hetao IDs might affect the regional hydro-climatic regimen and contribute to the discharge reduction at downstream gauges. The vegetation improvement is also observed in the lower reach IDs. The Qingtongxia-Hetao and the lower reach IDs would be human activities "hot spot" of the Yellow River drying up.