European Centre for Medium-Range Weather Forecasts The need to control gravity waves in data assimilation and the general concept of initialization are discussed. The basic method of non-linear normal-mode initialization is introduced, and aspects of its implementation in models are presented, covering the vertical and horizontal modal decomposition, implicit initialization and diabatic initial...

IRD), Paris, France, and Walker Institute, University of Reading, Reading, United Kingdom; WittenberG—GFDL, Princeton, New Jersey; Fedorov—Yale University, New Haven, Connecticut; Collins—Met Office, Hadley Centre, Exeter, United Kingdom; WanG—NOAA/AOML, Miami, Florida; Capotondi—University of Colorado, and NOAA, Boulder, Colorado; oldenborGh—KNMI, De Bilt, Netherlands; stoCkdale—ECMWF, Reading...

AFFILIATIONS: Guilyardi—LOCEAN/IPSL, Paris, France, and National Centre for Atmospheric Science–Climate, University of Reading, Reading, United Kingdom; wittEnbErG—NOAA/GFDL, Princeton, New Jersey; balMasEda—ECMWF, Reading, United Kingdom; cai—CSIRO, Aspendale, Victoria, Australia; collins— University of Exeter, Exeter, United Kingdom; McPhadEn— NOAA/PMEL, Seattle, Washington; watanabE—Universi...

Until 1991, operational NWP centers used to integrate a single control forecast starting from the analysis, which is the best estimate of the state of the atmosphere at the initial time. In December 1992, both NCEP and ECMWF started running ensembles of forecasts from slightly perturbed initial conditions (Molteni and Palmer, 1993, Buizza, 1997, Toth and Kalnay, 1993, Tracton and Kalnay, 1993, ...

1 Data Assimilation Research Centre, University of Reading, Reading, UK 2 Service Aeronomie, Universite Pierre et Marie Curie, Paris, France 3 ECMWF, Reading, UK 4 CNR-IFAC, Florence, Italy 5 University of Köln, Köln, Germany 6 BIRA-IASB, Brussels, Belgium 7 KNMI, De Bilt, The Netherlands 8 Met Office, Exeter, UK 9 Fusion Numerics, Boulder, Colorado, USA 10 CERFACS, Toulouse, France 11 Météo-Fr...

An improved version of RTIASI, the ECMWF fast radiative transfer model for the Infrared Atmospheric Sounding Interferometer, has been developed. In the new version of RTIASI (RTIASI-4) the accuracy of the fast transmittance model has been improved by including 4 more molecules (HNO3, CCl4, CF4 and OCS) in the line-by-line computations and by using the year 2000 release of the HITRAN molecular d...

The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistrytransport model. Our semi-inverse analysis uses the fifteen years (1979–1993) re-analysis of ECMWF meteorological data and annually varying emissions including photochemistry, in conjunction with observed CH4 concentration distributions an...

Global water vapour column amounts have been derived for the first time from measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on the European environmental satellite ENVISAT. For this purpose, two different existing retrieval algorithms have been adapted, namely the Air Mass Corrected Differential Absorption Spectroscopy (AMC-DOAS) which was ...

[1] Midlatitude cyclone tracks over the Southern Ocean are constructed for the 1999–2006 period using two surface data sets: European Centre for Medium-range Weather Forecasts (ECMWF) sea-level pressure analyses on one hand, and on the other hand modified analyses in which high-wavenumber pressure variability derived from scatterometer swaths has been injected with a wavelet-based method. A com...

Dust devils and nonrotating dusty plumes are effective uplift mechanisms for fine particles, but their contribution to the global dust budget is uncertain. By applying known bulk thermodynamic criteria to European Centre for Medium-Range Weather Forecasts (ECMWF) operational analyses, we provide the first global hourly climatology of potential dust devil and dusty plume (PDDP) occurrence. In ag...