梯度法计算空气动力学粗糙度存在的问题  

Problem of the Gradient Method to Study Aerodynamic Roughness

作　　者：邱玉珺[1] 吴风巨 刘志 

机构地区：[1]南京信息工程大学中国气象局大气物理与大气环境重点开放实验室,江苏南京210044 [2]内蒙古苏尼特左旗气象局,内蒙古苏尼特左旗026000

出　　处：《大气科学学报》2010年第6期697-702,共6页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(40705005);南京信息工程大学科研基金(20070128);江苏省青蓝工程资助项目

摘　　要：利用2009年春季内蒙古苏尼特左旗风速、空气温湿度的野外观测资料,用梯度法研究荒漠化草原区空气动力学粗糙度Z0时发现,Z0有明显的日、月分布规律。中性条件下,根据风速对Z0的不同影响可分为3个特征区。梯度法计算Z0有风速条件约束,只有在风速较大时计算的Z0真实可靠,确定可靠风速区域是正确应用梯度法计算Z0的关键。Z0随风速值的增大成指数关系递减,可从指数函数的收敛性确定Z0。Based on the observed wind velocity data, humidity and temperature data from April 20 to June 18,2009 in the Sonid Left Banner of Inner Mongolia, the aerodynamic roughness（ Z0 ） is studied and the gradient method calculated Z0 is discussed. The results show that Z0 has daily and monthly distribution characteristics obviously. Wind velocity has different effect on the Z0. When the wind field is under the neutral stability, there are 3 wind characteristic regions with different effect on Z0. Wind velocity is a constraint condition of the gradient method to study Z0. Only on the large wind velocity condition, the Zo calculated base on wind data is really reliable. Z0 is exponential descent with the wind velocity increasing. It can be determined by the exponential astringency.

关 键 词：风速对数廓线 粗糙度 摩擦风速 指数函数 

分 类 号：P433[天文地球—大气科学及气象学]