Impact of a Spectral Gravity Wave Parameterization on the Stratosphere in the Met Office Unified Model

Scaife, Adam A.; Butchart, Neal; Warner, Christopher D.; Swinbank, Richard

doi:10.1175/1520-0469(2002)059<1473:ioasgw>2.0.co;2

Cited by 136 publications

(162 citation statements)

References 69 publications

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“…Even though HIRDLS observes only part of the whole spectrum of gravity waves (only horizontal wavelengths > 100-200 km), this difference is probably too high to be explained by observational filter effects alone. This is further supported by several modeling studies that obtain much weaker gravity wave drag than ERA-Interim (e.g., Scaife et al, 2002;Osprey et al, 2010;Peña-Ortiz et al, 2010).…”

Section: Time Series In the Stratopause Regionsupporting

confidence: 70%

Driving of the SAO by gravity waves as observed from satellite

Ern¹,

Preusse²,

Riese³

2015

Ann. Geophys.

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Abstract. It is known that atmospheric dynamics in the tropical stratosphere have an influence on higher altitudes and latitudes as well as on surface weather and climate. In the tropics, the dynamics are governed by an interplay of the quasi-biennial oscillation (QBO) and semiannual oscillation (SAO) of the zonal wind. The QBO is dominant in the lower and middle stratosphere, and the SAO in the upper stratosphere/lower mesosphere. For both QBO and SAO the driving by atmospheric waves plays an important role. In particular, the role of gravity waves is still not well understood.In our study we use observations of the High Resolution Dynamics Limb Sounder (HIRDLS) satellite instrument to derive gravity wave momentum fluxes and gravity wave drag in order to investigate the interaction of gravity waves with the SAO. These observations are compared with the ERA-Interim reanalysis. Usually, QBO westward winds are much stronger than QBO eastward winds. Therefore, mainly gravity waves with westward-directed phase speeds are filtered out through critical-level filtering already below the stratopause region. Accordingly, HIRDLS observations show that gravity waves contribute to the SAO momentum budget mainly during eastward wind shear, and not much during westward wind shear. These findings confirm theoretical expectations and are qualitatively in good agreement with ERA-Interim and other modeling studies. In ERAInterim most of the westward SAO driving is due to planetary waves, likely of extratropical origin. Still, we find in both observations and ERA-Interim that sometimes westwardpropagating gravity waves may contribute to the westward driving of the SAO. Four characteristic cases of atmospheric background conditions are identified. The forcings of the SAO in these cases are discussed in detail, supported by gravity wave spectra observed by HIRDLS. In particular, we find that the gravity wave forcing of the SAO cannot be explained by critical-level filtering alone; gravity wave saturation without critical levels being reached is also important.

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Section: Time Series In the Stratopause Regionsupporting

confidence: 70%

Driving of the SAO by gravity waves as observed from satellite

Ern¹,

Preusse²,

Riese³

2015

Ann. Geophys.

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“…1) is accompanied by a westward bias just equatorward of the jet. This dipole structure to the bias is indicative of the jet being too strong because it is located too far poleward (possibly an issue with the way in which non-orographic gravity waves are attenuated in the upper stratosphere; Scaife et al, 2002). These biases in temperature and zonal wind are, as expected, largely removed in the nudged simulations (Fig.…”

Section: Metricsmentioning

confidence: 52%

The Met Office HadGEM3-ES chemistry–climate model: evaluation of stratospheric dynamics and its impact on ozone

et al. 2017

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Abstract. Free-running and nudged versions of a Met Office chemistry-climate model are evaluated and used to investigate the impact of dynamics versus transport and chemistry within the model on the simulated evolution of stratospheric ozone. Metrics of the dynamical processes relevant for simulating stratospheric ozone are calculated, and the free-running model is found to outperform the previous model version in 10 of the 14 metrics. In particular, large biases in stratospheric transport and tropical tropopause temperature, which existed in the previous model version, are substantially reduced, making the current model more suitable for the simulation of stratospheric ozone. The spatial structure of the ozone hole, the area of polar stratospheric clouds, and the increased ozone concentrations in the Northern Hemisphere winter stratosphere following sudden stratospheric warmings, were all found to be sensitive to the accuracy of the dynamics and were better simulated in the nudged model than in the free-running model. Whilst nudging can, in general, provide a useful tool for removing the influence of dynamical biases from the evolution of chemical fields, this study shows that issues can remain in the climatology of nudged models. Significant biases in stratospheric vertical velocities, age of air, water vapour, and total column ozone still exist in the Met Office nudged model. Further, these can lead to biases in the downward flux of ozone into the troposphere.

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“…The orographic gravity wave scheme allows for blocking as well as gravity wave drag and has been shown to improve the general circulation (McFarlane 1987, Webster et al 2003. Similarly, the spectral scheme has been shown to improve tropical stratospheric simulations (Scaife et al 2000(Scaife et al , 2002.…”

Section: Gravity Wave Dragmentioning

confidence: 99%

Implementation of the initial ACCESS numerical weather prediction system

Puri¹,

Dietachmayer²,

Steinle³

et al. 2013

AMOJ

135

103

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The Australian Community Climate and Earth-System Simulator (ACCESS) is a coupled climate and earth system simulator being developed as a joint initiative of the Bureau of Meteorology and CSIRO in cooperation with the university community in Australia. The main aim of ACCESS is to develop a national approach to climate and weather prediction model development. Planning for ACCESS development commenced in 2005 and significant progress has been made subsequently. ACCESS-based numerical weather prediction (NWP) systems were implemented operationally by the Bureau in September 2009 and were marked by significantly increased forecast skill of close to one day for three-day forecasts over the previously operational systems. The fully-coupled ACCESS earth system model has been assembled and tested, and core runs have been completed and submitted for the Intergovernmental Panel for Climate Change (IPCC) Fifth Assessment Report. Significant progress has been made with ACCESS infrastructure including successful porting to both Solar and Vayu (National Computational Infrastructure (NCI)) machines and development of infrastructure to allow usage by university researchers. This paper provides a description of the NWP component of ACCESS and presents results from detailed verification of the system.

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Impact of a Spectral Gravity Wave Parameterization on the Stratosphere in the Met Office Unified Model

Cited by 136 publications

References 69 publications

Driving of the SAO by gravity waves as observed from satellite

Driving of the SAO by gravity waves as observed from satellite

The Met Office HadGEM3-ES chemistry–climate model: evaluation of stratospheric dynamics and its impact on ozone

Implementation of the initial ACCESS numerical weather prediction system

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