European Centre for Medium-Range Weather Forecasts

European Centre for Medium Range Weather Forecast, Shinfield Park, Reading, RG2 9AX, UK e-mail johannes.flemming ecmwf int... 

ECMWF European Centre for Medium-Range Weather Forecasts... 

Hollingsworth, A., Capaldo, M., and Simmons, A. J. (1999). The scientific and technical foundation of the ECMWF strategy 1999-2008, European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading RG2 9AX, UK. 

A realistic simulation of real data was achieved using the model with a 56-km horizontal resolntion and 32 layers in the vertical. Numerical simulation for the forward trajectories was initialized at 0000 UTC April 18, and at 2100 UTC April 19, for the backward trajectory using ECMWF (European Centre for Medium-Range Weather Forecasts) analysis as the initial conditions. Initial fields of geopotential height, wind components and specific humidity, at ten standard pressure levels, were obtained by bihnear interpolation from the ECMWF operational initialized analyses. Time-dependent lateral boundary values were taken from the ECMWF analyses, linearly interpolated between the analyzed fields available at 6 h intervals. They were used at the outermost boundary points only. The row next to the outer boundary is a blend (four-point space interpolation) of the outer row and the third row inside, which is the outermost integration row of the model. 

While the production of such large amounts of OH from HO2 + RO2 reactions is unlikely, its inclusion in atmospheric models does facilitate investigation of the impact of underpredictions of OH in modelling studies. Butler et al. [4] found that increasing the OH concentration in a global 3D model European centre for medium-range weather forecasts-Hamburg/module earth submodel system... 

Schumann U (1989) Laige-eddy simulation of the turbulent diffusion with chemical reactions in the convective boundary layer. Atmos Environ 23(8) 1713-1727 Schumann U (1992) Simulations and parameterizations of laige eddies in convective atmospheric boundary layers. In Proceedings of a workshop held at the European Centre for Medium-Range Weather Forecasts (ECMWF) on Fine Scale Modelling and the Development of Parameterization Schemes, 16-18 September 1991, ECMWF Shames IH (1962) Mechemics of fluids. McGraw-Hill, New York... 

Computer simulations with an interactive chemistry GCM have been performed at T63 resolution (1.8° latitude and longitude). The chemistry GCM has been described by G.J. Roelofs and J. Lelieveld [Tellus 49B, 38 (1997)] and E. Roecknta- et aL [Journal of Climate, 12 3004 (1997)]. To represent actual meteorology, we assim-ilated analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF), as described by A,T.J. de Laat et al. (35). The T63 resolution model version has been evaluated by A,S. Kentarchos, G.J. Roelofs, and J. Lelieveld Journal of the Atmospheric Sciences, SI 2824 (2000)]. The chemistry scheme includes a representation of higher hydrocarbons as described by G.J. Roelofs and J. Lelieveld Journal of Geophysical Research, 105 22697 (2000)]. 

The current version of Enviro-HIRLAM has not previously been evaluated against ETEX-1 measurements. The ETX domain (Eig. 5.1) was used with at time-step fixed at 10 min, and initial and boundary conditions were post-processed from the European Centre for Medium-Range Weather Eorecasts operational model, IFS (Integrated Forecast System). No surface or upper air data assimilation was employed and the model was integrated 80 h into the future. The start time was on 23 October 1994 at 12 00 UTC, 4 h before the start of the release. Output was interpolated to measurement stations in order to compare to the observations and produce statistical measures. 

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