Temperature Variation Characteristics Analysis in the Ice Flood Season of the Yellow River Basin

摘要

This article is based on the daily mean temperature data of the Yellow River basin to analyze variation characteristics of average daily temperature and negative accumulated temperature of four sampling meteorological stations in the ice flood season by using statistical analysis,linear trend,the cumulative anomaly analysis and other methods.h attempts to explore the temperature variation characteristics and laws of the Yellow River basin in the ice flood season since 1950s.The results shows an increasing trend in general temperature change of the Yellow River basin in the ice flood season since 1950s.The warming rate of Baotou,Zhengzhou,Jinan,Beizhen was 0.6 °C/10 a,0.34 °C/l0 a,0.35 °C/10 a,0.38 °C/10 a respectively.In the ice flood season the negative accumulated temperature increasing rate of Baotou and Beizhen was 7.67 °C/a and 2.36 °C/a respectively,the total number of days which daily mean temperature were under 0 °C decreased by the rate of 3 d/10 a.Negative accumulated temperature variation characteristics and trends of Baotou station and Beizhen station are basically the same.On the premise of overall temperature upward trend,the temperature of the Yellow River basin before1985 was cold phase,from 1986 to 20l0 was warm phase,and abruptly change of temperature occurred around 1986 in which negative accumulated temperature rose and river frozen relatively weakened.Since the mid-1980s,the temperature and negative accumulated temperature of Ningxia-Inner Mongolia reach and the lower reach of the Yellow River have been increasing obviously that significantly influenced on the Freeze-up Time,the Break-up Time and the degree of river frozen.