高原气象2025，Vol.44Issue(3)：705-719,15.DOI:10.7522/j.issn.1000-0534.2024.00101
川南森林冠层上方动量和标量的湍流输送效率
Turbulent Transport Efficiency of Momentum and Sscalar over Forest Canopy in Southern Sichuan
摘要
Abstract
The turbulent transport characteristics of momentum and scalar over the canopy were studied by using the three levels(20 m,38 m and 56 m)turbulence data measured at the 60m forest micro meteorological tower in southern Sichuan from May 1 to June 30,2021.Coherent structure is the main form of turbulent motion,which is composed of updraft(ejection)and downdraft(sweep).In this paper,the quadrant analysis method is used to analyze the boundary of the roughness sublayer,roughness sublayer and constant flux layer above the for-est canopy and the ejection-sweep motion characteristics of the constant flux layer,including the difference of ejection and sweep contribution to flux,the difference between momentum and scalar transport,and the differ-ence between different scalar(T,q,CO2)transport.The results show that under unstable and stable conditions,the ejection dominates the scalar transport at all three levels,while the sweep is the main eddy current motion for scalar transport above the roughness sublayer under neutral conditions.For the momentum flux,under unstable conditions,the ejection dominates at all three levels.Under stable conditions,the ejection dominates at the roughness sublayer and the constant flux layer,while at the boundary of the roughness sublayer and the constant flux layer,the effect of the sweep is greater than that of the ejection.Under neutral conditions,the flux contribu-tion of the sweep is greater than that of the ejection except for the roughness sublayer.The third-order cumulant expansion method(CEM)can more accurately express the flux contribution caused by ejection and sweep,while the incomplete cumulant expansion method(ICEM)is poor in simulating the temperature at the boundary of roughness sublayer and constant flux layer.Through the calculation of transmission efficiency,the difference between momentum and scalar transmission is further quantified.The turbulent transfer efficiency of momentum decreases with increasing instability,while the heat transfer efficiency is the opposite.Atmospheric stability is an important factor controlling momentum and scalar transfer,and the transfer efficiency of water vapor is less af-fected by atmospheric stability.Under the condition of strong instability,the heat transfer efficiency is more ef-fective than other scalar transfer.关键词
象限分析/喷射扫掠/传输效率/森林冠层Key words
quadrant analysis/ejection-sweep/transport efficiencies/forest canopy分类
天文与地球科学引用本文复制引用
丁一,张宇,范德民,苏有琦,张茜,王严琪,王彦淇..川南森林冠层上方动量和标量的湍流输送效率[J].高原气象,2025,44(3):705-719,15.基金项目
国家自然科学基金项目(42275131) （42275131）
第二次青藏高原综合科学考察研究项目(2019QZKK010203) （2019QZKK010203）
