A computationally efficient nonstationary convective gravity‐wave drag parameterization for global atmospheric prediction systems

Kim, Young-Joon; Chun, Hye‐Yeong

doi:10.1029/2005gl024572

Cited by 4 publications

(3 citation statements)

References 28 publications

(44 reference statements)

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“…It is known that the mean meridional circulation is directed from the summer to winter pole in the middle atmosphere with downward/upward branch in the winter/summer pole [see, e.g., Dunkerton, 1978, Figure 4] which shows the solstice diabatic circulation, a good proxy for the monthly Figure 1a but with operational physics plus new orographic and convective gravity wave drag parameterization package. Note that ''GWD'' in this and subsequent figures denotes results with gravity wave drag by Kim and Doyle [2005] and Kim and Chun [2005] parameterizations. mean residual mean circulation).…”

Section: Secondary Model Bias In the Sea Level Pressurementioning

confidence: 99%

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Balance of drag between the middle and lower atmospheres in a global atmospheric forecast model

Kim

2007

J. Geophys. Res.

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[1] A global atmospheric forecast model that includes the middle atmosphere is used to investigate systematic model biases. As in many other global atmospheric models, Northern Hemispheric winter simulations from the vertically extended Navy Operational Global Atmospheric Prediction System reveal an unrealistic vertical tilt of the polar-night jet associated with a temperature bias in the northern polar middle atmosphere. This bias has important implication for satellite data assimilation in that inaccurate model background field associated with the bias can cause a data assimilation system to reject useful observation data. Efforts are made to alleviate this bias using improved radiation and orographic gravity wave drag parameterizations, the latter of which can provide adequate amount of drag to greatly reduce the bias, but at the cost of overestimated surface polar pressure. To understand and fix this secondary bias, this study addresses the cause and effect of the bias in terms of the balance of model drag mechanisms between the middle and lower atmospheres as well as within the lower atmosphere. Disruption of these balances in the model is argued to lead to degradation of surface simulation by reasonable middle atmospheric gravity wave drag despite an improvement in the middle atmospheric circulation. An experimental treatment of limiting the parameterized gravity wave drag to the middle atmosphere, as similarly done with a spectral gravity wave drag parameterization, is shown to largely alleviate the bias. This study discusses results from a series of winter and multiyear simulations, schematically illustrates the drag balance in the model, and investigates conservation of atmospheric angular momentum.

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Section: Secondary Model Bias In the Sea Level Pressurementioning

confidence: 99%

“…As in Figure1abut with operational physics plus new orographic and convective gravity wave drag parameterization package. Note that ''GWD'' in this and subsequent figures denotes results with gravity wave drag byKim and Doyle [2005] andKim and Chun [2005] parameterizations.…”

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confidence: 99%

Balance of drag between the middle and lower atmospheres in a global atmospheric forecast model

Kim

2007

J. Geophys. Res.

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“…Among the aforementioned sources of GWs, convection is well known as a major nonstationary GW source that generates GWs over a broad spectral range. To include the effects of convective GWs in GCMs, the parameterizations of convective GW drag (CGWD) have been developed and improved continuously [ Chun and Baik , 1998, 2002; Beres , 2004; Song and Chun , 2005, 2008; Kim and Chun , 2005; Chun et al , 2008; Choi and Chun , 2011]. Although significant theoretical and technical advances have been achieved in CGWD parameterizations, their realism in relation to observations has not been fully explored.…”

Section: Introductionmentioning

confidence: 99%

Comparison of gravity wave temperature variances from ray‐based spectral parameterization of convective gravity wave drag with AIRS observations

et al. 2012

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[1] The realism of ray-based spectral parameterization of convective gravity wave drag, which considers the updated moving speed of the convective source and multiple wave propagation directions, is tested against the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite. Offline parameterization calculations are performed using the global reanalysis data for January and July 2005, and gravity wave temperature variances (GWTVs) are calculated at z = 2.5 hPa (unfiltered GWTV). AIRS-filtered GWTV, which is directly compared with AIRS, is calculated by applying the AIRS visibility function to the unfiltered GWTV. A comparison between the parameterization calculations and AIRS observations shows that the spatial distribution of the AIRS-filtered GWTV agrees well with that of the AIRS GWTV. However, the magnitude of the AIRS-filtered GWTV is smaller than that of the AIRS GWTV. When an additional cloud top gravity wave momentum flux spectrum with longer horizontal wavelength components that were obtained from the mesoscale simulations is included in the parameterization, both the magnitude and spatial distribution of the AIRS-filtered GWTVs from the parameterization are in good agreement with those of the AIRS GWTVs. The AIRS GWTV can be reproduced reasonably well by the parameterization not only with multiple wave propagation directions but also with two wave propagation directions of 45 (northeast-southwest) and 135 (northwest-southeast), which are optimally chosen for computational efficiency.

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Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

et al. 2014

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Abstract. Gravity waves (GWs) with horizontal wavelengths of 32-2000 km are investigated during tropical cyclone (TC) Ivan (2008) in the southwest Indian Ocean in the upper troposphere (UT) and the lower stratosphere (LS) using observational data sets, radiosonde and GPS radio occultation data, ECMWF analyses and simulations of the French numerical model Meso-NH with vertical resolution < 150 m near the surface and 500 m in the UT/LS. Observations reveal dominant low-frequency GWs with short vertical wavelengths of 0.7-3 km, horizontal wavelengths of 80-400 km and periods of 4.6-13 h in the UT/LS. Continuous wavelet transform and image-processing tools highlight a wide spectrum of GWs with horizontal wavelengths of 40-1800 km, short vertical wavelengths of 0.6-3.3 km and periods of 20 min-2 days from modelling analyses. Both ECMWF and Meso-NH analyses are consistent with radiosonde and GPS radio occultation data, showing evidence of a dominant TCrelated quasi-inertia GW propagating eastward east of TC Ivan with horizontal and vertical wavelengths of 400-800 km and 2-3 km respectively in the LS, more intense during TC intensification. In addition, the Meso-NH model produces a realistic, detailed description of TC dynamics, some highfrequency GWs near the TC eye, variability of the tropospheric and stratospheric background wind and TC rainband characteristics at different stages of TC Ivan. A wave number 1 vortex Rossby wave is suggested as a source of dominant inertia GW with horizontal wavelengths of 400-800 km, while shorter scale modes (100-200 km) located at northeast and southeast of the TC could be attributed to strong localized convection in spiral bands resulting from wave number 2 vortex Rossby waves. Meso-NH simulations also reveal GWrelated clouds east of TC Ivan.

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A computationally efficient nonstationary convective gravity‐wave drag parameterization for global atmospheric prediction systems

Cited by 4 publications

References 28 publications

Balance of drag between the middle and lower atmospheres in a global atmospheric forecast model

Balance of drag between the middle and lower atmospheres in a global atmospheric forecast model

Comparison of gravity wave temperature variances from ray‐based spectral parameterization of convective gravity wave drag with AIRS observations

Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

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