CAJ | 학술논문

利用基于大气边界层Monin-Obukhov相似理论、通量守恒和质量守恒原理设计的非均匀地表空气动力学有效粗糙度计算方案,研究了3种不同地表类型情况下有效粗糙度的统计特征,并分析了大气层结稳定度和粗糙变率对有效粗糙度的影响.结果表明,有效粗糙度总是大于面积加权平均粗糙度,大部分情况下有效拖曳系数比平均拖曳系数大10%以上;有效粗糙度虽然和大气层结稳定度有关,但对粗糙变率更敏感,粗糙变率加倍将使有效粗糙度相对变化百分比达到加倍前的4倍,有效拖曳系数相对变化百分比达到加倍前的3倍.因此,非均匀下垫面的数值模式中,不能简单地采用面积加权平均粗糙度,需要采用能表示下垫面非均匀性综合效应的有效粗糙度.
이용기우대기변계층Monin-Obukhov상사이론、통량수항화질량수항원리설계적비균균지표공기동역학유효조조도계산방안,연구료3충불동지표류형정황하유효조조도적통계특정,병분석료대기층결은정도화조조변솔대유효조조도적영향.결과표명,유효조조도총시대우면적가권평균조조도,대부분정황하유효타예계수비평균타예계수대10%이상;유효조조도수연화대기층결은정도유관,단대조조변솔경민감,조조변솔가배장사유효조조도상대변화백분비체도가배전적4배,유효타예계수상대변화백분비체도가배전적3배.인차,비균균하점면적수치모식중,불능간단지채용면적가권평균조조도,수요채용능표시하점면비균균성종합효응적유효조조도.
With a new scheme of effective roughness length for heterogeneous terrain, based on the atmospheric boundary layer Monin-Obukhov similarity theory as well as flux and mass conservation principles, the statistical features of effective roughness length and its sensitivity to atmospheric stratification stability and roughness step for three surface category case are investigated. The results show that the effective roughness length is greater than the area-weighted logarithmic average one and the effective drag coefficient is more than 10%greater than the average one in most cases. The effective roughness length is much more sensitive to the roughness step, though it is dependent on the atmospheric stratification stability, and the relative percentage of effective roughness length and the effective drag coefficient will be 4 times and 3 times, respectively, for the double roughness step case. Therefore, the area-weighted average roughness length should be replaced by the effective one when the surface heterogeneity is considered in numerical models, which can represent the integrated effect of heterogeneous terrain.