This note has been prepared by the Physical Aspects Section of the Research Department at ECMWF. ECMWF is an operational centre for medium range weather forecasting, monthly forecasting, seasonal forecasting and ocean wave forecasting. The operational system is also used for re-analysis projects (ERA-15, ERA-40 and ERA-Interim). ECMWF operates a state of the art global atmospheric model with an...

Cloud and boundary layer variables from the European Centre for MediumRange Weather Forecasts (ECMWF) forecast model were compared with measurements made from surface instruments and from upward looking 8 mm wavelength radar and lidar at the Surface Heat Budget of the Arctic Ocean (SHEBA) ice camp during November and December of 1997. The precipitation accumulation, near-surface winds, and surf...

2. COMPARISON BETWEEN THE ECMWF 3DVAR AND 4DVAR SYSTEMS The ECMWF 4dVar system is, from the technical point of view, very similar to the 3dVar system. Both systems use the same unix scripts, and share much of the Fortran code. The same background error covariance matrix and observation operators are used, and most of the peripheral tasks such as fetching and archiving of fields and observations...

Radiosonde temperature profiles from Belgrano (78 S) and other Antarctic stations have been compared with European Centre for Medium-Range Weather Forecasting (ECMWF) and National Centers for Environmental Prediction (NCEP) operational analyses during the winter of 2003. Results show good agreement between radiosondes and NCEP and a bias in the ECMWF model which is height and temperature depend...

This paper presents three-dimensional prognostic O3 simulations with parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphere forecast model. We compare 5-day NOGAPS-ALPHA hindcasts of stratospheric O3 with satellite and DC-8 aircraft measurements for two cases during the SOLVE II campaign: (1) the cold, isolated vortex during 11–16 January 2003; and (2) the rapidly de...

A first validation of water vapour total column amounts derived from measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) in the visible spectral region has been performed. For this purpose, SCIAMACHY water vapour data have been determined for the year 2003 using an extended version of the Differential Optical Absorption Spectroscopy (DOAS) metho...

This letter addresses the link availability issue in satellite-based free space optical (FSO) communications. In particular, we present an accurate analysis for estimation of presence clouds and atmospheric turbulence. For this purpose, a meteorological ERA-Interim database, produced by European Center Medium Range Weather Forecast (ECMWF), is investigated. The obtained data is, then, used to a...

[1] In recent publications, a new basin-scale dataset of monthly variations in terrestrial water storage (BSWB) was derived for the ERA40 time period (1958–2002) using an atmospheric-terrestrial water-balance approach (Seneviratne et al., 2004; Hirschi et al., 2006). Here, we test the feasibility of using ECMWF operational forecast analyses – available for the recent time period in near real ti...

Clouds simulated by the European Centre for Medium-Range Weather Forecasts (ECMWF) model are composited to derive the typical organization of clouds surrounding a midlatitude baroclinic system. Comparison of this composite of about 200 cyclones with that based on satellite data reveals that the ECMWF model quite accurately simulates the general positioning of clouds relative to a low pressure c...

Middle atmosphere water vapour and dynamical features in aircraft measurements and ECMWF analyses D. G. Feist, A. J. Geer, S. Müller, and N. Kämpfer Institute of Applied Physics, University of Bern, Switzerland Data Assimilation Research Centre, University of Reading, UK now at: Max-Planck-Institute for Biogeochemistry, Jena, Germany now at: European Centre for Medium-Range Weather Forecasts (E...