R/S-based trend prediction of the factors that affect the groundwater resources changes in Minqin Oasis

To predict the influencing factors in the groundwater resources changes is one of preliminary work in predicting of the groundwater resource's changes, which plays an important role in using groundwater reasonably in arid areas, such as Minqin Oasis. This study uses a so-called R/S Analysis method to predict three major factors that affect the groundwater resources change in Minqin Oasis i.e. population, grain yield and the quantity of the upstream inflow. The results show that the Hurt index of the time series about the population in the Oasis is 0.733, which indicates that the future general changing trend of population in the Oasis is an increasing trend as the same as that in the period from 1960 to 2010. The Hurt index of the time series about grain yield in this Oasis is 0.901, which states that its future changing trend has a stronger long-term positive correlation with the increasing trend in the period from 1960 to 2010. In other words, its' future general changing trend is also increasing. The Hurt index of the quantity of upstream inflow in the Oasis is 0.916, which shows that its future general changing trend has a very strong long-term positive correlation with the decreasing trend in the period from 1960 to 2010, presenting a decreasing trend.