北方农牧交错带春季风速年际变化的影响因子分析  

Factors Related to the Interannual Variations of Spring Surface Winds over the Pastoral Transitional Zone in Northern China

作　　者：胡毅鸿 龚道溢[1,2,3] 毛睿 杨静[1,2,3] 石晓雪 HU Yihong;GONG Daoyi;MAO Rui;YANG Jing;SHI Xiaoxue(Key Laboratory of Environmental Change and Natural Disaster,Ministry of Education,Beijing Normal University,Beijing 100875,China;Academy of Disaster Reduction and Emergency Management,Beijing Normal University,Beijing 100875,China;Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学环境演变与自然灾害教育部重点实验室,北京100875 [2]北京师范大学减灾与应急管理研究院,北京100875 [3]北京师范大学地理科学学部,北京100875

出　　处：《高原气象》2020年第3期651-661,共11页Plateau Meteorology

基　　金：国家重点研发计划项目(2016YFA0602401);国家自然科学基金项目(41621061)。

摘　　要：利用北方农牧交错带1979-2016年15个台站的逐日风速资料、ERA-Interim再分析资料以及GLASS叶面积指数等,分析了该地区春季近地面风速的变化特征,以及大气环流因子和下垫面因子对风速年际变化的可能影响。研究表明,近38年来研究区风速的变化除了有显著的下降趋势(每10年约下降0.10 m·s^-1)外,还存在强烈的年际波动,年际方差占风速变化总方差的比例达58%。该地区风速的年际变化与东北亚地区的气旋性环流异常有密切关系,平均风速与该环流系统中心区700 hPa位势高度的相关系数高达-0.83。异常气旋性环流加强时,带来的偏西北风与研究区春季盛行西风叠加,加强近地面风速。分析表明东北亚异常气旋环流受北半球行星尺度大气环流变化的影响,与北极涛动显著相关(0.41)。下垫面状况的变化,通过动力和热力性质的改变可影响风速。计算表明叶面积指数与风速年际波动存在明显的反位相变化(r=-0.61),NDVI与风速相关不显著,这可能与叶面积指数能较好地反映空气动力学性质的变化有关。地表热通量的改变与风速的年际变化也具有显著的相关关系,风速与边界层高度、感热通量以及潜热通量年际变化的相关系数分别为0.57,0.39和-0.39;如果排除较强天气过程的可能影响,只计算小风日风速(<3 m·s^-1),则它们的年际相关更加显著,分别达到0.59,0.60和-0.57。The possible influence of the atmospheric circulation and the land surface factors on interannual varia‐tion of wind speed over pastoral transitional zone in northern China in spring has been investigated,by employ‐ing daily wind speed observations for 15 meteorological stations,the ERA-Interim reanalysis data,and the GLASS leaf area index data.The results show that,in addition to a weakening trend(-0.10 m·s^-1 per decade),the spring wind also experiments strong year-to-year variations.During the period of 1979-2016,the interannu‐al components accounts for 58%of the total variance.The wind interannual variability is strongly related to the anomalous cyclonic circulation in northeastern Asia.It strength,as being measured as the mean 700 hPa heights over 46°N-55°N and 116°E-130°E,has a significant correlation(-0.83)with the surface wind of the study ar‐ea.When the anomalous cyclonic circulation is strengthened,there is an anomalous northwesterly wind over pas‐toral transitional zone,which subsequently results in stronger winds.Interannual changes of the anomalous cy‐clonic circulation is related to the planetary atmospheric circulation over the northern hemisphere,as demonstrat‐ed by its significant correlation with the Arctic Oscillation(r=0.41).Surface roughness is an important aerody‐namic parameter with respect to the near surface vertical wind transport.Observations show that the leaf area in‐dex changes out-of-phase with wind speed.Annual scatter diagram shows that when the leaf area index increases 1 unit,the wind speed tends to decrease by approximate 1.57 m·s^-1.Their interannual variations from 1982-2014 yield a significant correlation of-0.61.There is also a negative correlation between NDVI and wind speed,but the correlation is not significant.It is probably because the leaf area index can better reflect the long-term vari‐ation of aerodynamic properties.The change of land surface physical conditions may also affect winds through the land-air heat flux.Analysis show that the in

关 键 词：北方农牧交错带 风速 年际变化 大气环流因子 下垫面因子 

分 类 号：P425.4[天文地球—大气科学及气象学]