Potential Vorticity Diagnostics to Quantify Effects of Latent Heating in Extratropical Cyclones. Part I: Methodology
Potential Vorticity Diagnostics to Quantify Effects of Latent Heating in Extratropical Cyclones. Part I: Methodology
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DOI：
10.1175/jas-d-17-0041.1
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发表时间：
2017-10
影响因子：
3.1
通讯作者：
D. Büeler;S. Pfahl
中科院分区：
文献类型：
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作者：
D. Büeler;S. Pfahl
温带气旋是由于斜压不稳定而发展起来的，但它们的加强往往被非绝热过程放大，最重要的是通过云的形成而产生的潜热。虽然这种放大对于单个气旋是很好的理解的，但仍然需要系统和定量地研究在不同的气候，特别是更温暖和更潮湿的气候下，黄体生成素如何影响气旋的加强。为此，作者引入了一种简单的诊断方法，在位涡(PV)框架内量化了Lh对气旋加强的贡献。PV趋势方程中的两个主要项，即非绝热PV修正和垂直平流，被用来推导一个诊断方程，以显式地计算由1H引起的气旋正的低对流层PV异常的比例。这种异常的强度与气旋强度及其在地面天气方面的相关影响密切相关。以评估其性能...
AbstractExtratropical cyclones develop because of baroclinic instability, but their intensification is often substantially amplified by diabatic processes, most importantly, latent heating (LH) through cloud formation. Although this amplification is well understood for individual cyclones, there is still need for a systematic and quantitative investigation of how LH affects cyclone intensification in different, particularly warmer and moister, climates. For this purpose, the authors introduce a simple diagnostic to quantify the contribution of LH to cyclone intensification within the potential vorticity (PV) framework. The two leading terms in the PV tendency equation, diabatic PV modification and vertical advection, are used to derive a diagnostic equation to explicitly calculate the fraction of a cyclone’s positive lower-tropospheric PV anomaly caused by LH. The strength of this anomaly is strongly coupled to cyclone intensity and the associated impacts in terms of surface weather. To evaluate the perfo...