Middle atmosphere variability in the UK Meteorological Office Unified Model
Middle atmosphere variability in the UK Meteorological Office Unified Model
复制标题
英国气象局统一模型中的中层大气变化
DOI：
10.1002/qj.49712454908
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Heaps
中科院分区：
文献类型：
--
作者：
R. Swinbank;C. S. Douglas;W. Lahoz;A. O'Neill;A. Heaps
本文描述了由英国气象局（UKMO）统一模型的平流层对流层配置模拟的平流层环流的季节演变。显示了该模型五年整合的结果。该模型对平流层及其季节演变的模拟与 UKMO 对流层-平流层数据同化系统产生的全球分析非常吻合。很好地模拟了两个半球冬季环流的对比。北半球冬季的纬向平均风表现出强烈的年际变化，而南半球冬季急流的变化则小得多。在北方凋零时，该模型自发地产生两次主要变暖和一些次要变暖。在南方冬季和春季，该模型很好地再现了极地涡旋的破裂以及通常在破裂之前的流态要素。然而，该模型确实存在许多缺点。由于缺乏位涡守恒，该模型无法捕获与平流层变暖和反气旋合并相关的流态的一些成分。平流层全年都有冷偏流，最大冷偏流位于平流层顶附近的冬季极地。这种温度偏差似乎是由于辐射方案长波部分的冷却偏差造成的。该模型在平流层上层也有不切实际的强烈行星波，尽管对流层上层和平流层下层的振幅与 UKMO 分析得出的结果非常一致。本文讨论了未来可能缓解这些问题的模型改进。
This paper describes the seasonal evolution of the stratospheric circulation simulated by a stratospheretroposphere configuration of the UK Meteorological Office (UKMO) Unified Model. Results are shown from a five‐year integration of the model. The model's simulation of the stratosphere and its seasonal evolution compares well with global analyses produced by the UKMO troposphere‐stratosphere data‐assimilation system. The contrast between the winter circulation in the two hemispheres is well simulated. The zonal‐mean winds show strong interannual variability in northern winter, while the southern hemisphere winter jet is much less variable. In northern wither the model spontaneously produces two major warmings and a number of minor warmings. In southern winter and spring the model reproduces well the break‐up of the polar vortex and elements of the flow regime that often precedes this break‐up. The model does, however, exhibit a number of shortcomings. Lack of conservation of potential vorticity prevents the model from capturing some of the ingredients of the flow regimes associated with stratospheric warmings and with the merger of anticyclones. There is a cold bias in the stratosphere throughout the year, with a maximum cold bias over the winter pole near the stratopause. This temperature bias appears to be due to a cooling bias in the long‐wave part of the radiation scheme. The model also has unrealistically strong planetary waves in the upper stratosphere, although amplitudes in the upper troposphere and lower stratosphere are in good agreement with those derived from the UKMO analyses. This paper discusses possible future model improvements that should alleviate these problems.