A numerical study of the development mechanisms of polar lows
A numerical study of the development mechanisms of polar lows
复制标题
极地低压发展机制的数值研究
DOI：
10.3402/tellusa.v37i5.11689
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发表时间：
1985
期刊：
影响因子：
2
通讯作者：
T. Warner
中科院分区：
文献类型：
--
作者：
J. M. Sardie;T. Warner
两个有据可查的极地低压，一个发生在大西洋，另一个在太平洋，数值模拟。这些数值结果与我们的分析结果进行了比较，以确定如何非线性和更完整的物理效应可能会修改我们的初步结论。在这项研究中使用的数值模式是宾夕法尼亚州立大学/国家大气研究中心（PSU/NCAR），三维（3-D）原始方程中尺度模式与高分辨率的行星边界层参数化和潮湿的物理。地表温度预测方程考虑了地表参数的变化，如辐射率、热惯量、热膨胀系数等。粗糙度和水分有效性。大西洋极地低发展在一个浅，但强烈的斜压区在丹麦海峡地区在第一个24小时的预测期。三维模式的敏感性研究表明，斜压性是足够的，以允许现实的发展，而极地低是在这个斜压区附近。然而，对流和非对流潜热加热和表面通量的感热和潜热是必要的模拟观察到的发展后，这个极地低离开这个斜压区，进入挪威海。事实上，对流和非对流潜热加热都是必不可少的模拟观察到的发展的大西洋极地低是与以前的分析模式的结果是一致的。与大西洋极地低压一样，太平洋极地低压也是在一个强烈的斜压带中发展起来的，但斜压带较深。敏感性研究表明，斜压性与非对流潜热加热，过度发展的极地低，不像分析结果。只有通过对流参数化和对流加热廓线的使用，才能正确地模拟太平洋极地低压的发展。表面通量在这一发展中发挥了很小的作用。因此，湿斜压性和CISK（第二类条件不稳定性）都是重要的大西洋和太平洋极地低压的观测发展。DOI：10.1111/j.1600-0870.1985.tb00444.x
Two well-documented polar lows, one occurring in the Atlantic Ocean and the other in the Pacific Ocean, are modeled numerically. These numerical results are compared with our analytic results in order to determine how the effects of nonlinearity and more complete physics may modify our tentative conclusions. The numerical model used in this study is The Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR), three-dimensional (3-D) primitive equation mesoscale model with a high-resolution planetary boundary-layer parameterization and moist physics. A prediction equation for ground temperature takes into account the existence of variable surface parameters such as albedo, emissivity, thermal inertia. roughness and moisture availability. The Atlantic polar low developed in a shallow but intense baroclinic zone in the Denmark Strait region during the first 24 h of the forecast period. Sensitivity studies with the 3-D model revealed that the baroclinity was sufficient to allow realistic development while the polar low was in the vicinity of this baroclinic zone. However, both convective and non-convective latent heating and the surface fluxes of sensible and latent heat were necessary for the simulation of observed development after this polar low departed from this baroclinic zone and entered the Norwegian Sea. The fact that convective and non-convective latent heating were both essential for simulating the observed development of the Atlantic polar low is consistent with previous analytic-model results. Like the Atlantic polar low, the Pacific polar low developed in an intense baroclinic zone, but this baroclinic zone was deep. Sensitivity studies revealed that baroclinity in conjunction with only non-convective latent heating, overdeveloped the polar low, unlike the analytic results. It was only through the use of the convective parameterization and the convective heating profile that correct development of the simulated Pacific polar low resulted. Surface fluxes played little role in this development. Thus, moist baroclinity and CISK (conditional instability of the second kind) were both important to the observed development of both the Atlantic and Pacific polar lows. DOI: 10.1111/j.1600-0870.1985.tb00444.x