The Impact of differences in old and new climate states on climate assessment operations in Qinghai Province

The differences of temperature and precipitation between the old and new climate states were compared and analyzed based on the temperature and precipitation data of 42 meteorological stations in Qinghai Province from 1961 to 2020,then discussed the influence of climate state change on climate operation.The results showed that the years with low temperature and low precipitation were increasing,while the years with high temperature and low precipitation were decreasing after activating new climate state.The effect of climate state change on temperature is more obvious than that of precipitation.The annual,seasonal and monthly average temperature,maximum temperature and minimum temperature all show increasing characteristics,with the most obvious increase in eastern agricultural areas,and the average temperature and the maximum temperature increase the most in spring .The minimum temperature increases the most in summer, the monthly average temperature and maximum temperature increase the most in February and April,and the minimum temperature increases the most in February,August and November.The annual and seasonal precipitation increased consistently,but the spatial distribution was different.The monthly precipitation decreased in December and increased in other months.After the change of climate average,the overall temperature and precipitation levels were adjusted from positive anomaly to negative anomaly,and the frequency of cold,warm winter and extreme climate events changed,which weakened the growth rate of extreme daily high temperature events and accelerated the deceleration of extreme daily low temperature events.