Impact of Climate Warming and Drying on Crop Growing Season in Northwestern Liaoning

Based on the observation data of the average temperature and precipitation of 8 national meteorological stations in the northwest region of Liaoning Province from April to October during 1961-2015,methods such as linear trend estimation,moving average,standard deviation and Mann-Kendall test are used to analyze the characteristics of average temperature and precipitation during the crop growing season in northwestern Liaoning.The results show that the average temperature during the crop growing season in the study area showed an upward trend,and the climate tendency rate was 0.193 ℃/10 a( P < 0.01).The largest contribution rate to temperature increase was in September,with a climate tendency rate of 0.27 ℃/10 a;the smallest contribution rate to the temperature increase was in July,with a climate tendency rate of 0.10 ℃/10 a.The warming trend was the most obvious in the second base year,with a climate tendency rate of 0.413 ℃/10 a( P < 0.01).The temperature was the lowest in the 1970s and the highest in the 2010s.The warming trend changed suddenly in 1996,and the sudden change reached a significant level of α = 0.05 after 2002.Precipitation was generally decreased,and the climate tendency rate was -7.68 mm/10 a.The decrease in precipitation was the most in July,and the climate tendency rate was -12.08 mm/10 a.The average temperature in the four base years failed to pass the correlation significance test.Among them,it showed an increasing trend in the second and third base year and a decreasing trend in the first and fourth base year.Rainfall was the highest in the 1960s and the lowest in the 1980s.After the abrupt change in 2002,precipitation decreased significantly.The research results provide reference for effective utilization of climate resources,rational adjustment of agricultural planting structure,and improvement of ecological environment quality.