000892721 001__ 892721 000892721 005__ 20210628150958.0 000892721 0247_ $$2doi$$a10.5194/acp-21-7695-2021 000892721 0247_ $$2ISSN$$a1680-7316 000892721 0247_ $$2ISSN$$a1680-7324 000892721 0247_ $$2Handle$$a2128/27838 000892721 0247_ $$2altmetric$$aaltmetric:106159409 000892721 0247_ $$2WOS$$aWOS:000655294100001 000892721 037__ $$aFZJ-2021-02288 000892721 041__ $$aEnglish 000892721 082__ $$a550 000892721 1001_ $$00000-0003-4377-2038$$aHindley, Neil P.$$b0$$eCorresponding author 000892721 245__ $$aStratospheric gravity waves over the mountainous island of South Georgia: testing a high-resolution dynamical model with 3-D satellite observations and radiosondes 000892721 260__ $$aKatlenburg-Lindau$$bEGU$$c2021 000892721 3367_ $$2DRIVER$$aarticle 000892721 3367_ $$2DataCite$$aOutput Types/Journal article 000892721 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1622016494_1381 000892721 3367_ $$2BibTeX$$aARTICLE 000892721 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000892721 3367_ $$00$$2EndNote$$aJournal Article 000892721 520__ $$aAtmospheric gravity waves (GWs) play an important role in atmospheric dynamics but accurately representing them in general circulation models (GCMs) is challenging. This is especially true for orographic GWs generated by wind flow over small mountainous islands in the Southern Ocean. Currently, these islands lie in the “grey zone” of global model resolution, where they are neither fully resolved nor fully parameterised. It is expected that as GCMs approach the spatial resolution of current high-resolution local-area models, small-island GW sources may be resolved without the need for parameterisations. But how realistic are the resolved GWs in these high-resolution simulations compared to observations? Here, we test a high-resolution (1.5 km horizontal grid, 118 vertical levels) local-area configuration of the Met Office Unified Model over the mountainous island of South Georgia (54∘ S, 36∘ W), running without GW parameterisations. The island's orography is well resolved in the model, and real-time boundary conditions are used for two time periods during July 2013 and June–July 2015. We compare simulated GWs in the model to coincident 3-D satellite observations from the Atmospheric Infrared Sounder (AIRS) on board Aqua. By carefully sampling the model using the AIRS resolution and measurement footprints (denoted as model sampled as AIRS hereafter), we present the first like-for-like comparison of simulated and observed 3-D GW amplitudes, wavelengths and directional GW momentum flux (GWMF) over the island using a 3-D S-transform method. We find that the timing, magnitude and direction of simulated GWMF over South Georgia are in good general agreement with observations, once the AIRS sampling and resolution are applied to the model. Area-averaged zonal GWMF during these 2 months is westward at around 5.3 and 5.6 mPa in AIRS and model sampled as AIRS datasets respectively, but values directly over the island can exceed 50 mPa. However, up to 35 % of the total GWMF in AIRS is actually found upwind of the island compared to only 17 % in the model sampled as AIRS, suggesting that non-orographic GWs observed by AIRS may be underestimated in our model configuration. Meridional GWMF results show a small northward bias (∼20 %) in the model sampled as AIRS that may correspond to a southward wind bias compared to coincident radiosonde measurements. Finally, we present one example of large-amplitude (T′≈15–20 K at 45 km altitude) GWs at short horizontal wavelengths (λH≈30–40 km) directly over the island in AIRS measurements that show excellent agreement with the model sampled as AIRS. This suggests that orographic GWs in the full-resolution model with T′≈45 K and λH≈30–40 km can occur in reality. Our study demonstrates that not only can high-resolution local-area models simulate realistic stratospheric GWs over small mountainous islands but the application of satellite sampling and resolution to these models can also be a highly effective method for their validation. 000892721 536__ $$0G:(DE-HGF)POF4-511$$a511 - Enabling Computational- & Data-Intensive Science and Engineering (POF4-511)$$cPOF4-511$$fPOF IV$$x0 000892721 588__ $$aDataset connected to CrossRef, Journals: juser.fz-juelich.de 000892721 7001_ $$00000-0003-2496-953X$$aWright, Corwin J.$$b1$$eCorresponding author 000892721 7001_ $$00000-0001-9890-403X$$aGadian, Alan M.$$b2 000892721 7001_ $$0P:(DE-Juel1)129125$$aHoffmann, Lars$$b3 000892721 7001_ $$0P:(DE-HGF)0$$aHughes, John K.$$b4 000892721 7001_ $$0P:(DE-HGF)0$$aJackson, David R.$$b5 000892721 7001_ $$00000-0003-3315-7568$$aKing, John C.$$b6 000892721 7001_ $$0P:(DE-HGF)0$$aMitchell, Nicholas J.$$b7 000892721 7001_ $$00000-0002-9670-6715$$aMoffat-Griffin, Tracy$$b8 000892721 7001_ $$0P:(DE-HGF)0$$aMoss, Andrew C.$$b9 000892721 7001_ $$00000-0002-1117-4351$$aVosper, Simon B.$$b10 000892721 7001_ $$00000-0002-8631-3512$$aRoss, Andrew N.$$b11 000892721 773__ $$0PERI:(DE-600)2069847-1$$a10.5194/acp-21-7695-2021$$gVol. 21, no. 10, p. 7695 - 7722$$n10$$p7695 - 7722$$tAtmospheric chemistry and physics$$v21$$x1680-7324$$y2021 000892721 8564_ $$uhttps://juser.fz-juelich.de/record/892721/files/acp-21-7695-2021.pdf$$yOpenAccess 000892721 909CO $$ooai:juser.fz-juelich.de:892721$$pdnbdelivery$$pdriver$$pVDB$$popen_access$$popenaire 000892721 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)129125$$aForschungszentrum Jülich$$b3$$kFZJ 000892721 9130_ $$0G:(DE-HGF)POF3-511$$1G:(DE-HGF)POF3-510$$2G:(DE-HGF)POF3-500$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bKey Technologies$$lSupercomputing & Big Data$$vComputational Science and Mathematical Methods$$x0 000892721 9131_ $$0G:(DE-HGF)POF4-511$$1G:(DE-HGF)POF4-510$$2G:(DE-HGF)POF4-500$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$aDE-HGF$$bKey Technologies$$lEngineering Digital Futures – Supercomputing, Data Management and Information Security for Knowledge and Action$$vEnabling Computational- & Data-Intensive Science and Engineering$$x0 000892721 9141_ $$y2021 000892721 915__ $$0StatID:(DE-HGF)0200$$2StatID$$aDBCoverage$$bSCOPUS$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0160$$2StatID$$aDBCoverage$$bEssential Science Indicators$$d2021-02-02 000892721 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0 000892721 915__ $$0StatID:(DE-HGF)1150$$2StatID$$aDBCoverage$$bCurrent Contents - Physical, Chemical and Earth Sciences$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)9905$$2StatID$$aIF >= 5$$bATMOS CHEM PHYS : 2019$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0501$$2StatID$$aDBCoverage$$bDOAJ Seal$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0500$$2StatID$$aDBCoverage$$bDOAJ$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0113$$2StatID$$aWoS$$bScience Citation Index Expanded$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0700$$2StatID$$aFees$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0150$$2StatID$$aDBCoverage$$bWeb of Science Core Collection$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess 000892721 915__ $$0StatID:(DE-HGF)0030$$2StatID$$aPeer Review$$bDOAJ : Peer review$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0561$$2StatID$$aArticle Processing Charges$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0100$$2StatID$$aJCR$$bATMOS CHEM PHYS : 2019$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0300$$2StatID$$aDBCoverage$$bMedline$$d2021-02-02 000892721 915__ $$0StatID:(DE-HGF)0199$$2StatID$$aDBCoverage$$bClarivate Analytics Master Journal List$$d2021-02-02 000892721 920__ $$lyes 000892721 9201_ $$0I:(DE-Juel1)JSC-20090406$$kJSC$$lJülich Supercomputing Center$$x0 000892721 980__ $$ajournal 000892721 980__ $$aVDB 000892721 980__ $$aUNRESTRICTED 000892721 980__ $$aI:(DE-Juel1)JSC-20090406 000892721 9801_ $$aFullTexts