Abstract:
Based on climatic data from 1960 to 2014 obtained from nine meteorological stations in Huludao and Chaoyang,rainfall changes,agricultural rainfall satisfactory and occurrence rules of drought during the growing season (from April to September) in the western region of Liaoning province were studied using methods of an accumulated moisture index and a moisture index.The results show that rainfall during growing season shows a downward trend from 1960 to 2014 for Huludao and Chaoyang.For recent 20 years,rainfall in the growing season decreases 8.7% and 11.1% for the southern and northern areas of Songling Mountain,respectively.The time ranges with decreased rainfall are during the period from July to September.For recent 55 years,moisture index of growing season decreases with climate tendency rates of-0.023/10 a and-0.015/10 a for the southern and northern areas of Songling Mountain,respectively.Drought occurrence frequency shows an upward trend in recent 20 years with occurrence frequencies increasing 30.0% and 25.0% for the southern and northern areas of Songling Mountain,respectively.Growing season's agricultural rainfall satisfactory decreased in recent 55 years with decreasing percentages of 11.8% and 11.2% for the southern and northern areas of Songling Mountain,respectively.Decreasing of growing season's agricultural rainfall satisfactory in Huludao and Chaoyang is attributed to the decline in precipitation.As a result,occurrence frequency of drought increases,which makes agriculture production face a threat.Therefore,to relieve the loss caused by drought damage,we should improve the management of water resources,increase efficiency of water use and adjust planting structure of agriculture.