The partial thin plate smoothing splines method was applied to evaluate spatiotemporal trends of precipitation in the Yellow River basin from 1981 to 2013 by considering the basin's digital elevation model. Results indicate the following. (1) The spline method can greatly improve the spatial interpolation accuracy of meteorological data and can be applied to spatial modeling of meteorological elements for large regions with complex terrain. (2) Overall, annual precipitation in the Yellow River basin shows a decreasing trend from east to west, with the isohyet equipluve distribution of 400 mm being basically consistent with the dividing line between semi-humid and semi-arid regions in China. Sichuan has the highest annual average precipitation while Neimeng has the lowest; Shandong and Henan both have relatively significant changes of annual precipitation while Gansu and Qinghai have small changes. (3) The average monthly precipitation of the basin from 1981 to 2013 presents an overall increasing trend from north to south; the annual precipitation in each province was mainly concentrated in 7–9 months of the whole year. The highest monthly average precipitation in most provinces occurred in July, while the highest at Ningxia occurred in August. Results may provide a scientific basis for understanding future precipitation changes and improving our ability to cope with climate change.
- partial thin plate smoothing splines
- spatial interpolation
- spatio-temporal trend
- Yellow River basin
- First received 17 January 2016.
- Accepted in revised form 14 April 2016.
- © IWA Publishing 2016