气候波动对典型草原区潜在蒸散的影响  

Impact of climatic vacillation on potential evaporation on typical grassland

作　　者：白美兰[1] 郝润全[2] 侯琼 邸瑞琦[1] 杨晶[1] 

机构地区：[1]内蒙古自治区气候中心,内蒙古呼和浩特010051 [2]内蒙古气象科技服务中心,内蒙古呼和浩特010051 [3]内蒙古气象科研所,内蒙古呼和浩特010051

出　　处：《大气科学学报》2011年第3期351-355,共5页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(30760102)

摘　　要：根据FAO推荐的彭曼—孟蒂斯方程,利用典型草原区1961—2008年25个地面气象站资料,分析了典型草原区潜在蒸散量的变化趋势以及与气候波动间的关系。结果表明,1)典型草原区四季与年潜在蒸散量均呈现出一致的减少趋势,且春季潜在蒸散量减少趋势最为显著,减少率为3.71mm/(10a),其次为夏季和秋季,冬季最少。典型草原区年潜在蒸散量的80%以上集中在牧草返青、生长关键期,且此时又是潜在蒸散量变幅最大的季节,由此可能引发典型草原区干旱事件频发、地上生物量减少、草场的退化。2)对典型草原区潜在蒸散量影响最为密切的因子为:相对湿度、降水量、日照时数和平均风速,气温影响不显著。究其原因从能量平衡原理分析,典型草原区近50a平均风速减少影响了空气动力学对蒸散的影响,日照时数减少和湿度的略增是太阳辐射减少的原因,从而导致了潜在蒸散量的降低。3)21世纪典型草原区潜在蒸散量处于低的平均态和变率增大时期,极有可能引发干旱灾害,这与目前该地区气候变暖后生态耗水加大、干旱化加剧、生态退化严重等结论是一致的。Based on the Panman-Monteith method by FAO and the weather data from 1961 to 2008 at 25 weather stations,the correlation between potential evaporation and climatic vacillation on typical grassland is analyzed.The result shows that：1） The seasonal and annual potential evaporation is on a decreasing trend on typical grassland.The potential evaporation in spring declines most at 3.71 mm/（10 a）.It is followed by summer and autumn evaporation,and winter evaporation shows the least decrease.More than 80% of the annual potential evaporation occurs during the periods of grass ventilation reventilization and growth.It is the period when evaporation fluctuates most in a whole year.This might induce severe drought events,aboveground biomass decrease and grassland degradation on typical grassland.2） Potential evaporation on typical grassland is most closely related to such factors as relative humidity,precipitation,sunshine hours and average wind speed instead of temperature.From the view of energy equilibrium,this could be explained by the decline of average wind speed in the recent 50 years affecting evaporation aerodynamically.Radiation reduces because of sunshine hour decline and humidity increase,which causes the decline of evaporation.3） The evaporation on typical grassland is low and fluctuates a lot in this century,which will probably induce severe drought disaster.It is in accordance with the conclusion from recent studies showing the ecological water consumption increases and more severe droughts and ecological degradation occur after climate warming

关 键 词：典型草原区 彭曼-孟蒂斯方程 潜在蒸散 气候波动 

分 类 号：S812.8[农业科学—草业科学]