大柴旦地区降雨、温度及蒸发变化特征分析

Variation of Rainfall,Temperature and Evaporation in the Region of Da Chaidan

【目的】探索影响雨养农业生产的关键气象要素温度、降水和蒸发的变化特征。【方法】以大柴旦1956—2017年的逐月降水量、温度、蒸发量数据为基础,采用线性倾向估计法、Mann-Kendall突变检验法、Morlet小波分析方法对该地区的降水量、温度、蒸发量进行了系统分析。【结果】大柴旦地区降水量呈增多趋势,温度呈增高趋势,蒸发量呈减小趋势;通过改进的Mann-Kendall突变检验法确定2001—2002年为降水量序列上升突变点,温度序列未发生突变,1998—1999年为蒸发量序列的减少突变点。降水量序列存在8、19 a和29 a左右的变化周期;温度序列存在5、9、14 a和19 a左右的周期;蒸发量序列存在10 a和18 a左右的周期。【结论】预测大柴旦地区未来几年降水量处于小周期减少期,温度处于增高阶段,蒸发量将处于减少期。

【Objective】Precipitation,temperature and evapotranspiration are factors controlling water resource dynamics and crop growth in a region.Taking the region of Da Chaidan as an example,this paper analyzed their evolution over the past 50 years.【Method】Monthly meteorological data measured from 1956 to 2017 at different weather stations across the region of Da Chaidan were used in the analysis.Linear tendency estimation,Mann-Kendall test and Morlet wavelet analysis were used to analyze the characteristics of precipitation,temperature and evaporation.【Result】Precipitation and temperature had both been in increase while the evaporation had been in a decline during the studied period.Mann-Kendall test showed that 2001—2002 was the abrupt changing point for precipitation,while 1998—1999 was the abrupt changing point for evaporation.In contrast,the temperature did not show any abnormal change during this period.Three periodicities were identified for precipitation:8,19,and 29 years,four for temperature:5,9,14 and 19 years,and two for evaporation:10 and 18 years.【Conclusion】Precipitation in the region of Da Chaidan is likely to enter a reduction cycle in the coming years,while the temperature is likely to rise and annual evaporation decreases.