Characteristics of Frost Climate Change in Recent 50 Years in Gonghe Area of Qinghai Province

Using the ground meteorological observation data during 1961-2010 years in Hainan State meteorological observatory of Qinghai Province,and using climatic statistical methods,the characteristics of frost season climate and its changes were analyzed,for a comprehensive analysis of frost climate change in the last 50 years in Gonghe area of Qinghai Province and providing the scientific basis of agricultural production and rational utilization of climate resources in the area.The results showed that last frost date in almost 50years was significantly ahead of trends,at a rate of 4.5 d every 10 years in advance,and 23 d ahead of last frost date in 50 years.The first frost date was postponed trends,at a rate of 7.1 d every 10years later,and first frost date pushed back 35 d in 50 years.The beginning(end) ahead of frost(postponed) had a probability of 42%(52%).Description of the last frost damage was greater than the first frost.First and last frost date and the length of the frost-free period appeared closely related to the temperature.As temperatures rise,gradually early frost delay,and last frost date in advance gradually,and the frost-free period extended.In terms of the impact,maximum temperature and minimum temperatures affected more than the average temperature.Maximum temperature,minimum temperature were positive associated with the mean temperature and the first frost days and frost-free season,and the last frost date was negative,and showed a very good relationship on the interannual scales.