water Article Spatial and Temporal Variation Characteristics of Snowfall in the Haihe River Basin from 1960 to 2016 Xu Wu 1,2, Su Li 1,3,*, Bin Liu 1,3,* and Dan Xu 1 1 School of Water Conservancy and Hydroelectric Power, Hebei University of Engineering, Handan 056021, China;
[email protected] (X.W.);
[email protected] (D.X.) 2 Hydrology and Water Resources Survey Bureau of Handan, Handan 056001, China 3 Hebei Key Laboratory of Intelligent Water Conservancy, Handan 056001, China * Correspondence:
[email protected] (S.L.);
[email protected] (B.L.); Tel.: +86-310-312-3077 (S.L.); +86-310-312-3702 (B.L.) Abstract: The spatio-temporal variation of precipitation under global warming had been a research hotspot. Snowfall is an important part of precipitation, and its variabilities and trends in different regions have received great attention. In this paper, the Haihe River Basin is used as a case, and we employ the K-means clustering method to divide the basin into four sub-regions. The double temperature threshold method in the form of the exponential equation is used in this study to identify precipitation phase states, based on daily temperature, snowfall, and precipitation data from 43 meteorological stations in and around the Haihe River Basin from 1960 to 1979. Then, daily snowfall data from 1960 to 2016 are established, and the spatial and temporal variation of snowfall in the Haihe River Basin are analyzed according to the snowfall levels as determined by the national meteorological department. The results evalueted in four different zones show that (1) the snowfall at each meteorological station can be effectively estimated at an annual scale through the exponential equation, for which the correlation coefficient of each division is above 0.95, and the relative error is Citation: Wu, X.; Li, S.; Liu, B.; Xu, D.