Effects of El Nino/La Nina Events on Climate of Yulin Area of Shaanxi Province

Based on the meteorological and historical data in Yulin area of Shaanxi Province from 1961to present,statistical analysis was conducted.The objectives of this study were:(1)Examine the relationship among precipitation,temperature,natural disaster events,and the ENSO(El Nino/Southern Oscillation) events.(2)Reveal the correlation between ENSO events and the climate of Yulin area.(3)Identify the periodicity of the precipitation and temperature changes.The results show that since 1954,the climate was warming significantly in Yulin area,with an annual temperature increasing rate of 0.025℃per year.However,the annual total precipitation decreased at rate of 1.740mm per year.In El Nino years,the temperature was 0.12℃ higher than that in normal years,and in La Nina years,the annual average temperature remained same to that in normal years.El Nino event lowered annual total precipitation approximately 8mm than the normal years,while La Nina events did approximately 3mm.The temperature and precipitation of the area changed at a short period of 3years and a long period of 20years.ENSO events was prone to cause high temperature and drought disasters,and ENSO warming events caused more meteorological disasters than ENSO cold events in the study area according to statistical analysis.