Evolution of a subgrid deep convection parametrization in a limited‐area model with increasing resolution

Abstract

SUMMARYThe adaptation of a convective parametrization to high resolution has been successfully performed, to a certain point, by refinements in the representation of the entrainment, detrainment and some other features of the original general-circulation-model oriented scheme. But, passing to resolutions below 10 km requires dispensing with some fundamental hypotheses, starting with quasi-equilibrium and the assumption of negligible up-and downdraught mesh fractions. A prognostic scheme has been used for the draughts' vertical velocities and mesh fractions. The prognostic closure of the convective scheme has many benefits, but additional enhancements are required, starting with a coherent treatment of the cloud condensates and a more integrated combination of the different schemes producing condensation, cloud and precipitation.

Reinitialised versus continuous regional climate simulations using ALARO-0 coupled to the land surface model SURFEXv5

“…This ALARO-0 model configuration has been operated at the Royal Meteorological Institute of Belgium for its operational numerical weather forecasts since 2010. The new physical parameterisation within the ALARO-0 model was specifically designed to run at convection-permitting scales, with a particular focus on an improved convection and cloud scheme (Gerard and Geleyn, 2005;Gerard, 2007;Gerard et al, 2009). The ALARO-0 model domain is centred over western Europe at 46.47 • N and 2.58 • E with a dimension of 149×149 horizontal grid points and spacing of 20 km in both horizontal axes, with a Lambert conformal projection (Fig.…”

The Central European limited‐area ensemble forecasting system: ALADIN‐LAEF

“…In addition to the components listed for ALARO, this configuration includes the new parametrization scheme 3MT (Modular Multiscale Microphysic and Transport; Gerard and Geleyn, 2005;Gerard, 2007;Piriou et al, 2007;Geleyn et al, 2008;Gerard et al, 2009), which was mainly developed in order to deliver physically consistent results over a wide range of model resolutions, in particular for resolutions between 7 and 3 km. The use of the diagnostic convection scheme as used for ALADIN-25 and ALARO becomes obsolete.…”

Overview of the first HyMeX special observation period over Croatia

“…1b). The convection scheme used in the high-resolution model is modular multiscale microphysics and a transport (3MT) scheme for precipitation and clouds (Gerard and Geleyn, 2005;Gerard, 2007;Gerard et al, 2009).…”

“…Vertical discretization 37 hybrid pressure type eta coordinates (Simmons and Burridge, 1981) Equation system Prognostic equations for condensates (Catry et al, 2007) Horizontal diffusion SLHD (Váňa et al, 2008) Time scheme SETTLS (Hortal, 2002) with a second-order accurate treatment of the non-linear residual (Gospodinov et al, 2001) Lateral boundary coupling Davies (1976) zone 8 grid-points wide, time dependent (Haugen and Machenhauer, 1993) at the end of the grid-point computations (Radnóti, 1995) LBC data From ARPEGE, 3 hourly 6 h forecast from 8 km run, hourly (Tudor and Termonia, 2010) Initial conditions Stanešić (2011): 3DVar (Courtier et al, 1998;SSDFI (Termonia, 2008) Lorenc, 1986) and optimal interpolation for surface Microphysics prognostic cloud water and ice, rain and snow (Catry et al, 2007) statistical approach for sedimentation of precipitation (Geleyn et al, 2008) Radiation (Ritter and Geleyn, 1992) based on Geleyn and Hollingsworth (1979) and enhanced recently (Geleyn et al, 2005a, b) Turbulence TKE according to Geleyn et al (2006), modified from Louis et al (1982) includes the shallow convection (Geleyn, 1987) Soil scheme ISBA (Noilhan and Planton, 1989), also used in the surface data assimilation (Giard and Bazile, 2000) Diagnostics of 10 m wind using a parameterised vertical profile (Geleyn, 1988) and 2 m temperature dependent on stability Convection diagnostic convection scheme (Geleyn et al, 1995) prognostic convection scheme (Gerard and Geleyn, 2005;Gerard, 2007) combines resolved and convective contributions (Gerard et al, 2009) During SOP1, several upper-level troughs entered the western Mediterranean and induced cyclogenesis over the Gulf of Genoa, Tyrrhenian Sea and Adriatic Sea. Figure 3 shows the mean sea level pressures and low-level horizontal winds for IOP4, IOP9, IOP13, IOP16, IOP18 and IOP19.…”