Gravity wave drag estimation from global analyses using variational data assimilation principles. II: A case study.
An estimate of the three-dimensional gravity-wave drag field derived from middle-atmosphere analyses is presented. It is obtained using a novel technique based on variational data assimilation principles described in Part I. The assimilation is performed for a one-week period starting on 1 July 2002...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/16931 |
| Acceso en línea: | http://hdl.handle.net/11336/16931 |
| Access Level: | acceso abierto |
| Palabra clave: | Adjoint Model Middle Atmosphere Parameter Estimation Twin Experiments https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
| Sumario: | An estimate of the three-dimensional gravity-wave drag field derived from middle-atmosphere analyses is presented. It is obtained using a novel technique based on variational data assimilation principles described in Part I. The assimilation is performed for a one-week period starting on 1 July 2002 using Met Office middle-atmosphere analyses as the observations as well as the initial condition. The rotational component of the gravity-wave drag is robustly estimated by the technique. The zonal-mean drag estimates reach maximum amplitudes of 50 m s−1day−1 at 0.4 hPa near the winter-hemisphere polar jet. In the middle stratosphere, drag estimates are much weaker with zonal-mean peak values of 5 m s−1day−1 and show transient small-scale features not obviously correlated with the local background flow. Vertical variations in the sign and pattern of the estimated drag suggest filtering of the gravity-wave spectrum by the background flow. |
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