Diverse Dynamical Response to Orographic Gravity Wave Drag Hotspots—A Zonal Mean Perspective

Šácha, Petr; Kuchař, Aleš; Eichinger, Roland; Pišoft, Petr; Jacobi, Ch.; Rieder, Harald E.

doi:10.1029/2021gl093305

Cited by 7 publications

(1 citation statement)

References 66 publications

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“…Recently, there is also a growing interest in the SOD over Northeast Asia which is one of the OGW hotspot regions in the world (Šácha et al., 2015). However, these studies mainly focused on the impacts of stratospheric MWD on the large‐scale circulation in the middle atmosphere (e.g., Kuchar et al., 2020; Šácha et al., 2021, 2016). In our earlier work (Zhang et al., 2020), the impacts of parameterized SOD on the East Asian summer monsoon circulation and precipitation were examined according to a series of numerical sensitivity experiments.…”

Section: Introductionmentioning

confidence: 99%

Impact of Parameterized Topographic Drag on a Simulated Northeast China Cold Vortex

Zhong³

et al. 2023

JGR Atmospheres

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Northeast China cold vortex (NECV) is the major influencing weather system in northern China. Yet the impacts of complex terrain on the evolution of NECV remains poorly understood. This work studies the influence of subgrid orographic drag (SOD) on a heavy‐rain‐producing NECV occurred in July 2011 using the Weather Research and Forecasting model. A series of numerical experiments are conducted with different parameterizations of SOD including turbulent orographic form drag (TOFD), flow blocking drag (FBD), and mountain wave drag (MWD). Results show that the NECV intensity is overestimated in the absence of SOD parameterization, accompanied with too‐low geopotential height (GPH) and too‐strong horizontal winds. The parameterization of TOFD can significantly decelerate the 10‐m winds, whereas the FBD and MWD play a minor role. However, the influence of TOFD is overwhelmed by FBD and MWD in the troposphere, especially the latter. This implies that the breaking of mountain waves play a more important role in weakening the NECV than the low‐level flow blocking. The lower‐tropospheric MWD directly weakens the convergence and ascent motion of the NECV, producing an anti‐cyclonic circulation that uplifts the GPH under the constraint of quasi‐geostrophic vertical vorticity. This MWD‐induced circulation indirectly weakens the NECV in the mid‐upper troposphere by producing a warm advection that counters the low‐level cold advection to the southwest of the NECV. The findings provide useful insights into the impacts of complex terrain on the NECV and highlight the importance of topographic drag parameterization in the simulation and short‐range forecast of NECV.

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Section: Introductionmentioning

confidence: 99%

Impact of Parameterized Topographic Drag on a Simulated Northeast China Cold Vortex

Zhong³

et al. 2023

JGR Atmospheres

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Parameterized orographic gravity wave drag and dynamical effects in CMIP6 models

Hájková,

Šácha

2023

Clim Dyn

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Orographic gravity waves (OGWs) are an important mechanism for coupling of the free atmosphere with the surface, mediating the momentum and energy transport and influencing the dynamics and circulation especially in the middle-atmosphere. Current global climate models are not able to resolve a large part of the OGW spectrum and hence, OGW effects have to be parameterized in the models. Typically, the only parameterized effect is the OGW induced drag. Despite producing the same quantity as an output and relying on similar assumptions (e.g. instantaneous vertical propagation), the individual OGW parameterization schemes differ in many aspects such as handling of the orography, the inclusion of non-linear effects near the surface and the tuning of the emergent free parameters. In this study, we have reviewed 7 different parameterizations, which are used in 9 different CMIP6 models. We report pronounced differences in the vertical distribution and magnitude of the parameterized OGW drag between the models and study to what extent the inter-model differences can be traced back to the difference in the type and tuning of the schemes. Finally, we demonstrate how the OGW drag differences project to the intermodel differences in the stratospheric dynamics. The study can pave the way for a more systematic research of the OGW parameterizations in the future, with an ultimate goal of lowering the amount of uncertainty of the future climate projections connected with the parameterized effects of unresolved orography.

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Importance of orographic gravity waves over the Tibetan Plateau on the spring rainfall in East Asia

Li,

Xu,

et al. 2023

Sci. China Earth Sci.

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Diverse Dynamical Response to Orographic Gravity Wave Drag Hotspots—A Zonal Mean Perspective

Cited by 7 publications

References 66 publications

Impact of Parameterized Topographic Drag on a Simulated Northeast China Cold Vortex

Impact of Parameterized Topographic Drag on a Simulated Northeast China Cold Vortex

Parameterized orographic gravity wave drag and dynamical effects in CMIP6 models

Importance of orographic gravity waves over the Tibetan Plateau on the spring rainfall in East Asia

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