An overview of the past, present and future of gravity‐wave drag parametrization for numerical climate and weather prediction models

Kim, Young‐Joon; Eckermann, Stephen D.; Chun, Hye‐Yeong

doi:10.3137/ao.410105

Cited by 337 publications

(145 citation statements)

References 267 publications

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“…Future boundary layer parametrization schemes for coarse scale atmospheric weather and climate models that do not (or not entirely) resolve these flows should consider these valley geometry parameters beside other effects such as different land-use types, surface forcings and background stabilities. The development of such a parametrization will be quite difficult, but could be based on a similar technique as applied in gravity wave drag parametrizations of coarse-resolution models (see Kim et al, 2003). This means that the subgridscale topography of a model grid box could be reduced to an idealized valley-plain topography with certain geometry properties by means of Fourier analysis.…”

Section: Discussionmentioning

confidence: 99%

Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys

2015

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Abstract. Idealized numerical simulations of thermally driven flows over various valley-plain topographies are performed under daytime conditions. Valley floor inclination and narrowing valley cross sections are systematically varied to study the influence of along-valley terrain heterogeneity on the developing boundary layer structure, as well as horizontal and vertical transport processes. Valley topographies with inclined valley floors of 0.86 • increase upvalley winds by a factor of about 1.9 due to smaller valley volumes (volume effect) and by a factor of about 1.6 due to additional upslope buoyancy forces. Narrowing the valley cross section by 20 km per 100 km along-valley distance increases upvalley winds by a factor of about 2.6. Vertical mass fluxes out of the valley are strongly increased by a factor between 1.8 and 2.8 by narrowing the valley cross sections and by a factor of 1.2 by inclining the valley floor. Trajectory analysis shows intensified horizontal transport of parcels from the foreland into the valley within the boundary layer in cases with inclined floors and narrowing cross sections due to increased upvalley winds.

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Section: Discussionmentioning

confidence: 99%

Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys

2015

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“…For example, one of the major GW sources, convection, is often assumed to be uniformly distributed all over the globe in GCMs with spectral GWD parameterization schemes, which is obviously far from reality (Alexander and Rosenlof, 2003). The other important non-stationary GW source -jet imbalances -is not included in most of the GCMs (Kim et al, 2003). Secondly, different observational instruments can only see partial gravity wave spectra.…”

Section: Introductionmentioning

confidence: 99%

Gravity wave variances and propagation derived from AIRS radiances

Gong

Eckermann

2012

Atmos. Chem. Phys.

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Abstract. As the first gravity wave (GW) climatology study using nadir-viewing infrared sounders, 50 Atmospheric Infrared Sounder (AIRS) radiance channels are selected to estimate GW variances at pressure levels between 2-100 hPa. The GW variance for each scan in the cross-track direction is derived from radiance perturbations in the scan, independently of adjacent scans along the orbit. Since the scanning swaths are perpendicular to the satellite orbits, which are inclined meridionally at most latitudes, the zonal component of GW propagation can be inferred by differencing the variances derived between the westmost and the eastmost viewing angles.Consistent with previous GW studies using various satellite instruments, monthly mean AIRS variance shows large enhancements over meridionally oriented mountain ranges as well as some islands at winter hemisphere high latitudes. Enhanced wave activities are also found above tropical deep convective regions. GWs prefer to propagate westward above mountain ranges, and eastward above deep convection. AIRS 90 field-of-views (FOVs), ranging from +48 • to −48 • off nadir, can detect large-amplitude GWs with a phase velocity propagating preferentially at steep angles (e.g., those from orographic and convective sources). The annual cycle dominates the GW variances and the preferred propagation directions for all latitudes. Indication of a weak two-year variation in the tropics is found, which is presumably related to the Quasi-biennial oscillation (QBO).AIRS geometry makes its out-tracks capable of detecting GWs with vertical wavelengths substantially shorter than the thickness of instrument weighting functions. The novel discovery of AIRS capability of observing shallow inertia GWs will expand the potential of satellite GW remote sensing and provide further constraints on the GW drag parameterization schemes in the general circulation models (GCMs).

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“…Gravity waves (GWs) significantly impact global circulations by accelerating or decelerating the background wind while dissipating or breaking (e.g., McLandress, 1998;McIntyre, 1998;Kim et al, 2003;. For example, GWs are important in driving the quasi-biennial oscillation (QBO) (e.g., Dunkerton, 1997;Ern and Preusse, 2009;Alexander and Ortland, 2010;Evan et al, 2012;Ern et al, 2014;Kim and Chun, 2015) and the semiannual oscillation (SAO) .…”

Section: Introductionmentioning

confidence: 99%

Tuning of a convective gravity wave source scheme based on HIRDLS observations

Trinh¹,

Kalisch²,

Preusse³

et al. 2016

Atmos. Chem. Phys.

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Abstract. Convection as one dominant source of atmospheric gravity waves (GWs) has been the focus of investigation over recent years. However, its spatial and temporal forcing scales are not well known. In this work we address this open issue by a systematic verification of free parameters of the Yonsei convective GW source scheme based on observations from the High Resolution Dynamics Limb Sounder (HIRDLS). The instrument can only see a limited portion of the gravity wave spectrum due to visibility effects and observation geometry. To allow for a meaningful comparison of simulated GWs to observations, a comprehensive filter, which mimics the instrument limitations, is applied to the simulated waves. By this approach, only long horizontalscale convective GWs are addressed. Results show that spectrum, distribution of momentum flux, and zonal mean forcing of long horizontal-scale convective GWs can be successfully simulated by the superposition of three or four combinations of parameter sets reproducing the observed GW spectrum. These selected parameter sets are different for northern and southern summer. Although long horizontal-scale waves are only part of the full spectrum of convective GWs, the momentum flux of these waves is found to be significant and relevant for the driving of the QBO (quasi-biennial oscillation). The zonal momentum balance is considered in vertical cross sections of GW momentum flux (GWMF) and GW drag (GWD). Global maps of the horizontal distribution of GWMF are considered and consistency between simulated results and HIRDLS observations is found. The latitude dependence of the zonal phase speed spectrum of GWMF and its change with altitude is discussed.

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An overview of the past, present and future of gravity‐wave drag parametrization for numerical climate and weather prediction models

Cited by 337 publications

References 267 publications

Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys

Influence of along-valley terrain heterogeneity on exchange processes over idealized valleys

Gravity wave variances and propagation derived from AIRS radiances

Tuning of a convective gravity wave source scheme based on HIRDLS observations

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