Bibliographic Details
| Title: |
Evaluating Parameterizations for Turbulent Fluxes over the Landfast Sea-Ice Surface in Prydz Bay, Antarctica. |
| Authors: |
Cheng, Fangyuan1 (AUTHOR), Yang, Qinghua1 (AUTHOR), Liu, Changwei1 (AUTHOR) liuchw8@mail.sysu.edu.cn, Han, Bo1 (AUTHOR), Peng, Shijie1 (AUTHOR), Hao, Guanghua2 (AUTHOR) |
| Source: |
Advances in Atmospheric Sciences. Oct2023, Vol. 40 Issue 10, p1816-1832. 17p. |
| Subject Terms: |
*Eddy flux, *Parameterization, *Latent heat, *Water vapor, *Sea ice, *Heat flux, *Ice cores, *Hygrothermoelasticity |
| Geographic Terms: |
Antarctica |
| Abstract (English): |
It is crucial to appropriately determine turbulent fluxes in numerical models. Using data collected in East Antarctica from 8 April to 26 November 2016, this study evaluates parameterization schemes for turbulent fluxes over the landfast sea-ice surface in five numerical models. The Community Noah Land Surface Model with Multi-Parameterizations Options (Noah_mp) best replicates the turbulent momentum flux, while the Beijing Climate System Model (BCC_CSM) produces the optimum sensible and latent heat fluxes. In particular, two critical issues of parameterization schemes, stability functions and roughness lengths, are investigated. Sensitivity tests indicate that roughness lengths play a decisive role in model performance. Based on the observed turbulent fluxes, roughness lengths over the landfast sea-ice surface are calculated. The results, which can provide a basis for setting up model parameters, reveal that the dynamic roughness length (z0m) increases with the increase of frictional velocity (u*) when u* ⩽ 0.4 m s−1 and fluctuates around 10−3 m when u* > 0.4 m s−1; thermal roughness length (z0t) is linearly related to the temperature gradient between air and sea-ice surface (ΔT) with a relation of lg(z0t) = −0.29ΔT−3.86; and the mean water vapor roughness length (z0q) in the specific humidity gradient (Δq) range of Δq ⩽ −0.6 g kg−1 is 10−6 m, 3.5 times smaller than that in the range of Δq > −0.6 g kg−1. [ABSTRACT FROM AUTHOR] |
| Abstract (Chinese): |
摘 要: 描述地气湍流交换是数值模式中不可或缺的一环。本研究基于我国南极第三十二次科考观测数据,对北极区域气候系统模式(ARCSYM)、欧洲中期天气预报中心-集成预报系统 (ECMWF-IFS)、大气分量模式(CAM)、北京气候中心气候系统模式(BCC_CSM)和陆面过程模式(Noah_mp)中的海冰表面湍流通量参数化方案的表现进行了综合评估。结果表明,Noah_mp模拟湍流动量通量表现最好,BCC_CSM模拟湍流感热和潜热通量表现最好。本研究还对模拟表现起关键作用的两个参数(稳定度函数和粗糙度长度)进行了评估,结果表明粗糙度长度的选取对参数化方案模拟效果的影响远远大于稳定度函数。基于此,本研究基于观测数据进一步明确了该观测站点粗糙度长度的最优区间:当摩擦速度u* ≤ 0.4 m s−1时,动力粗糙度长度(z0m)会随着u*增加而增加,当u* > 0.4 m s−1时, z0m保持在10-3 m左右;热力粗糙度长度(z0t)与冰‐气温度梯度(ΔT)满足lg(z0t) = −0.29 × ΔT−3.86;当比湿梯度Δq ≤ −0.6 g kg−1时,水汽粗糙度长度(z0q)平均值为10-6 m,比Δq ˃ −0.6 g kg−1时的z0q平均值小3.5倍。 [ABSTRACT FROM AUTHOR] |
| Database: |
Energy & Power Source |
