Modelling and parametrization of the convective flow over leads in sea ice and comparison with airborne observations
Modelling and parametrization of the convective flow over leads in sea ice and comparison with airborne observations
复制标题
海冰中导线对流的建模和参数化以及与机载观测的比较
DOI：
10.1002/qj.3953
复制
发表时间：
2021
影响因子：
8.9
通讯作者：
Hartmann
中科院分区：
文献类型：
--
作者：
Michaelis;Lüpkes;Schmitt;Hartmann
一个非涡分辨的微尺度模型被应用于模拟三个不同的引线（海冰中的细长通道）上的对流，这是2013年在北极边缘冰区上空由飞机观测到的。该研究旨在评估局部和非局部湍流参数化的质量。后者代表了一种与铅宽相关的湍流通量方法，该方法是针对大气边界层（ABL）中铅垂直、近中性入流的理想条件而设计的，该边界层在250至350 m高度左右被强逆温覆盖。这里考虑的观测情况也以几乎垂直于铅的流动为特征，但是与理想条件相比，我们的分析涵盖了稳定流入条件和更浅ABL的影响。模型模拟使用观测到的表面参数和逆风剖面进行初始化，并将结果与铅上方和顺风处获得的测量结果进行比较。与铅产生的对流有关的基本观测特征可以用两种封闭来再现，但是观测到的羽流倾斜和穿透羽流在逆温层附近的垂直夹带被低估了。非局部闭合的优势通过更真实地表示具有观测到的垂直卷吸或观测暗示反梯度输运的区域而变得明显。通过与观测结果的比较表明，通过确定与取数相关的逆温高度和指定一个参数来确定作为逆风ABL分层函数的羽流倾斜度，可以进一步改进非局部闭合所获得的结果。这两种效应都改善了通量、边界层变暖和垂直卷吸的代表性。该模式还能够再现观测到的在前缘上空弱低空急流消失的情况，但无论使用何种闭合，其顺风再生和相关的动量输送并不总是很好地捕捉到。
A non‐eddy‐resolving microscale model is applied to simulate convection over three different leads (elongated channels in sea ice), which were observed by aircraft over the Arctic Marginal Ice Zone in 2013. The study aims to evaluate the quality of a local and a non‐local turbulence parametrization. The latter represents a lead‐width‐dependent approach for the turbulent fluxes designed for idealised conditions of a lead‐perpendicular, near‐neutral inflow in an atmospheric boundary layer (ABL) capped by a strong inversion at around 250 to 350 m height. The observed cases considered here are also characterised by an almost lead‐perpendicular flow but, in comparison to the idealised conditions, our analysis covers effects in stable inflow conditions and a much shallower ABL. The model simulations are initialised with observed surface parameters and upwind profiles, and the results are compared with measurements obtained above and downwind of the leads. The basic observed features related to the lead‐generated convection can be reproduced with both closures, but the observed plume inclination and vertical entrainment near the inversion layer by the penetrating plume are underestimated. The advantage of the non‐local closure becomes obvious by the more realistic representation of regions with observed vertical entrainment or where the observations hint at counter‐gradient transport. It is shown by comparison with the observations that results obtained with the non‐local closure can be further improved by including the determination of a fetch‐dependent inversion height and by specifying a parameter determining the plume inclination as a function of the upwind ABL stratification. Both effects improve the representation of fluxes, boundary‐layer warming, and vertical entrainment. The model is also able to reproduce the observed vanishing of a weak low‐level jet over the lead, but its downwind regeneration and related momentum transport are not always well captured, irrespective of the closure used.
登录
查看更多内容
使用不同的湍流参数化对北极对流边界层进行建模
影响因子：
4.3
作者：
Christof L�pkes;K. Heinke Schl�nzen
通讯作者：
K. Heinke Schl�nzen
影响因子：
--
作者：
M. Zulauf;S. Krueger
通讯作者：
S. Krueger
影响因子：
5.2
作者：
Batrak, Yurii;Mueller, Malte
通讯作者：
Mueller, Malte
影响因子：
4.3
作者：
J. W. Glendening;S. Burk
通讯作者：
S. Burk
1992 年北极铅实验 (LEADEX) 期间浮冰和铅表面能量预算的重新计算
影响因子：
--
作者：
P. Persson;D. Ruffieux;C. Fairall
通讯作者：
C. Fairall