大气科学2018，Vol.42Issue(1)：52-69,18.DOI:10.3878/j.issn.1006-9895.1704.16269
边界层参数化方案在“灰色区域”尺度下的适用性评估
Assessment of the Suitability of Planetary Boundary Layer Schemes at "Grey Zone" Resolutions
摘要
Abstract
As the resolution in numerical weather prediction models increases,turbulent motion can be partially resolved by grid scale dynamics.However,a substantial part of turbulent motion still needs to be parameterized,which results in the so-called "grey zone" problem.Assessment of the suitability of traditional PBL (Planetary Boundary Layer) schemes at "grey zone" resolutions would provide foundation for future improvement of PBL schemes,making them more adaptive to the variation of resolutions.In this study,the authors assess the performance of four PBL schemes that are commonly used in WRF,i.e.YSU (Yonsei University),MYJ (Mellor-Yamada-Janjic),MYNN (Mellor-Yamada-Nakanishi-Niino Level 2.5) and MYNN3 in the simulation of convective PBL at "grey-zone" resolutions using LES (Large-Eddy Simulation).Results indicate that at higher resolutions,domain-averaged potential temperature increases in the mixing layer with local PBL schemes such as MYJ and MYNN2.5,while subgrid scale flux decreases and falls below the reference value constructed from LES.The nonlocal terms in YSU hardly change with grid size and do not show distinct scale-sensitivity.In contrast,the counter-gradient term in MYNN3 decreases with reduced grid-size and exhibits a certain degree of scale-sensitivity.The strong nonlocal subgdd mixing in YSU results in a weak,stable stratification in the mixing layer and suppresses resolved-scale turbulence mixing,thus impeding the onset of convectively induced secondary circulations in the model.The suitability of PBL schemes at "grey zone" resolutions varies with certain resolutions.For example,at the resolution of 500 m,none of the four PBL schemes performs well to accurately simulate both the thermal structure and turbulent statistics in the PBL.关键词
边界层参数化方案/灰色区域/大涡模拟/非局地输送Key words
PBL parameterization schemes/Grey zone/LES (Large-Eddy Simulation)/Nonlocal mixing分类
天文与地球科学引用本文复制引用
刘梦娟,张旭,陈葆德..边界层参数化方案在“灰色区域”尺度下的适用性评估[J].大气科学,2018,42(1):52-69,18.基金项目
国家自然科学基金项目41505087、41575101,国家重点研发计划“政府间科技合作项目”重点专项2016YEE0109700 National Natural Science Foundation of China (Grants 41505087,41575101),National Key Research and Development Program of China (2016YFE0109700) （Grants 41505087,41575101）
