A case study of turbulent flux and counter gradient transport in the convective boundary layer
K-theory is one of the most extensive turbulent closure revision schemes using weather patterns.However,because it cannot explain the counter-gradient transportation phenomenon,it must be corrected.There are three turbulent closure revision schemes representative of the convective boundary layer(CBL):the first was developed by Deardorff(1972),the second scheme by Holtslag and Moeng (1991),and the third by Liu Feng(2001).Because these schemes are based on different physical assumptions,they present different parameterizations and interpretations of counter-gradient transportation within the CBL.In the present work,using part of the published database obtained from the WL-ARPDD94 Experiment in Xianghe,the three schemes were tested and compared.The results showed that the first scheme systematically underestimates the heat flux within the entire CBL,and is inconsistent with the observations of the Xianghe CBL Experiment.The second scheme can reproduce inverse gradient transportation phenomena in most of the CBL,and can basically depict the vertical distribution of turbulent flux.However,it is not in agreement with observations in the lower and upper CBL.The third scheme's counter-gradient item is related to height,reaching a maximum in the central CBL,while the other two schemes' counter-gradient items remain constant with changes in height.The third scheme's results are not only consistent with the second scheme in most of the CBL,but can also reasonably describe the turbulent flux distribution within the entire CBL.Liu's parameterization exhibits good agreement with observations in the whole CBL.The analysis suggests that Liu's scheme,first used to determine heat flux based on field experiment data,is able to represent the heat flux profile for the CBL.On the basis of reviewing the physical interpretation of counter-gradient transport phenomena by the different closure schemes,a universal scheme for the planetary boundary layer,suitable for numerical weather forecasting models,is urgently needed.
国家科技期刊平台
NSTL
万方数据
维普
