【作者】 鞠英芹；

【导师】 刘寿东； 刘绍民；

【作者基本信息】 南京信息工程大学 ， 城市气象学， 2012， 硕士

【摘要】 地气相互作用是气候系统的重要组成部分,也是地球系统和全球气候变化研究的基础。深入研究地气相互作用,更合理、恰当地描述关键地表参数（空气动力学粗糙度、热力学粗糙度）,能够改进区域能量平衡的估算,并提高陆面模式和遥感模型模拟结果的准确性。本项研究利用馆陶站、阿柔站和北京325米气象塔自动气象站和涡动相关仪的观测资料,估算了其空气动力学粗糙度和热力学粗糙度,分析了其时空变化特征,并将估算值与相应参数化方案进行了比较。主要研究结论为：（1）通过分析比较,确定Yang et al（2003）方法为空气动力学粗糙度的最优算法,其计算结果能准确地反映出农田和草地两种下垫面空气动力学粗糙度的季节性变化特征。农田下垫面的空气动力学粗糙度随风向变化明显,草地下垫面的空气动力学粗糙度随风向变化不明显。空气动力学粗糙度季节性变化与植被高度呈显著线性关系,与叶面积指数呈抛物线关系。通过将不同参数化方案的计算结果与估算值进行比较,发现每种方案在不同下垫面都有一定的局限性,不同参数化方案的表现并不完全一致。对于农田、草地下垫面而言,计算结果与估算值较为接近的参数化方案分别为M_z0m4、M_z0m1。（2）各种下垫面的kB-1值的日变化具有一定的频率分布规律。除玉米下垫面、玉米和裸地混合下垫面之外,其余下垫面的kB"1均呈现抛物线型日变化,与地气温差密切相关。均匀植被下垫面kB-1值的变化呈正态分布,用均值、中值的kB-1计算感热通量的估算误差在2%左右,因此可以将该类下垫面的kB-1赋予一个常数进行研究。而在其他下垫面,kB-1都是一个难以确定的变化量,需另外建立适合的kB-1参数化模型。通过对7种参数化方案的感热通量计算值与观测值之间的比较发现,裸地下垫面的计算结果与观测值最为接近的参数化方案是M₁989a、M₁998方案；混合地表下垫面的计算结果与观测值最为接近的参数化方案是M₁958、M₁963、M₂007b方案。M₁982方案、M₂002方案存在局限性,不适合本项研究中的下垫面。（3）北京城市下垫面的空气动力学粗糙度具有明显的方向性,在盛行风向90°～180°范围内计算出的z0m值达到1.78m;热力学粗糙度有明显的变化范围且具有一定的频率分布规律。城市下垫面的z0m值和kB-1的统计值明显高于郊区下垫面（农田和草地）下垫面。更多还原

【Abstract】 The land-atmosphere interaction is not only an important part of the climate system, but also the foundation of studying the earth system and global climate change. It provides a more reliable basis for the improvement of regional energy balance estimate and atmospheric numerical model, in-depth understanding of land-atmosphere interaction by describing the key land surface parameters （z0m, z0h） more reasonably and more aptly. In this paper, based on the data of Eddy Covariance （EC） system and Automatic Weather Station （AWS） collected at Guantao, A’Rou sites in2010and Beijing325m tower in2007, the value of z0m and zoh are estimated. And then the characteristics of spatial and temporal change are analyzed with these estimation values, which are compared with the ones modeling by different parameterization schemes. The result shows that（1） Yang et al.（2003） is the best method of all estimation ones chose here and its calculation results reveals seasonal variation of z0m in both crop and grass surfaces accurately. Contrast to A’Rou site, the directional characteristics of z0m is obvious in Guantao site. The value of aerodynamic roughness length changes with wind direction due to the morphological character difference of the roughness elements within corresponding source areas on various wind direction. In addition, the z0m is essentially related to characteristics of the roughness elements, which showing a linear relationship with the vegetation height and a parabolic relationship with Leaf Area Index （LAI）. Meanwhile, different parameterization method has its own limitations on various land types, in which the results using M_zom4and M_zoml is most close to the estimation ones at Guantao and A’Rou sites, respectively.（2） The values of kB-1have a obvious range on different underlying surface, which has a diurnal variation and also a good correlation with surface-air temperature difference, except maize and maize/bare soil surface. On uniform vegetation, the change of kB-1exhibits a normal distribution pattern. The sensible heat flux error is about2%with a median or mean value of kB-1, so that kB-1can set at a fixed value on this surface. On others, kB-1is a changing value and need model modeling. Comparing sensible heat flux using seven parameterization schemes with the observed values, results of M₁989a and M₁998are most close to the observe value on bare soil while on mixed terrain surface, M₁958, M₁963and M₂007b are the best ones compared with observe value. M₁982and M₂002both have limitation on all surfaces.（3） On Beijing city underlying surface, z0m has obvious directivity,1.78m in the prevailing wind direction from90degree to180degree. kB-1has obvious variation range, and has a certain pattern of frequency distribution. Comparing with underlying surface of suburb （farmland and grassland）, statistical values of kB-1is significantly higher.更多还原