Next generation weather prediction atmospheric models will have horizontal resolution of about 3-5 km. The problem dimension will be 1010. One will need to use efficiently 104-105 computational cores ...to make a practical operational forecast. This leads to the need for the deep revision of numerical methods and algorithms used in atmospheric models. One of the problems to be solved is the horizontal discretization of atmospheric dynamics equations on the quasi-uniform spherical grids. This problem can be investigated using shallow water model that is much computationally cheaper than the use of full atmosphere model. We are developing an atmospheric dynamics solver for the next generation numerical weather prediction model at the Institute of Numerical Mathematics and Hydrometeorological center of Russia. Within this work, the solver for the shallow water equations using gnomonic cubed-sphere grid has been developed. The solver is verified using standard shallow water test cases. The accuracy of the presented solver is analysed. The good agreement to the reference solutions is achieved, when 4-th order spatial approximations are used.
The global atmosphere model SL-AV is applied for operational numerical weather prediction in Russia at the time scales from days to month and also for simulation of modern climate. It is important to ...achieve the best wall-clock time for all of the model applications with different grid sizes. In this paper, we analyse the effect of switching computations and parallel exchanges from double to single precision in the semi-Lagrangian advection and elliptic equations solver blocks on the quality of the medium-range forecast and evaluate the change in wall-clock time. We have also optimized OpenMP parallelization in the computations of the right-hand sides of meteorological prognostic equations. The effect of these changes is studied for SL-AV model versions with different resolutions.
Development of the multiscale version of the global atmosphere model SL-AV required many improvements in the dynamical core, replacement or refinement of parameterization algorithms and complex ...tuning of the model. These modifications were initially tested with the experiments on modern climate simulation and then incorporated into the model configuration for medium-range numerical weather prediction. The impact of these model improvements on forecast quality is studied in this paper. The increase in accuracy of model climate characteristics has led to the reduction of forecast errors. The comparison of quality for numerical forecasts starting from the initial data of Hydrometcenter of Russia and ECMWF is carried out. The effect of replacing the initial data turned out to be comparable to the effect of multi-year works on model development. This shows the importance and necessity of development and improvement of the Hydrometcenter of Russia data assimilation system.
SL-AV (semi-Lagrangian, based on the absolute vorticity equation) is a global hydrostatic atmospheric model. Its latest version, SL-AV20, provides global operational medium-range weather forecast ...with 20 km resolution over Russia. The lower-resolution configurations of SL-AV20 are being tested for seasonal prediction and climate modeling. The article presents the model dynamical core. Its main features are a vorticity-divergence formulation at the unstaggered grid, high-order finite-difference approximations, semi-Lagrangian semi-implicit discretization and the reduced latitude–longitude grid with variable resolution in latitude. The accuracy of SL-AV20 numerical solutions using a reduced lat–lon grid and the variable resolution in latitude is tested with two idealized test cases. Accuracy and stability of SL-AV20 in the presence of the orography forcing are tested using the mountain-induced Rossby wave test case. The results of all three tests are in good agreement with other published model solutions. It is shown that the use of the reduced grid does not significantly affect the accuracy up to the 25 % reduction in the number of grid points with respect to the regular grid. Variable resolution in latitude allows us to improve the accuracy of a solution in the region of interest.
An algorithm for stochastic perturbation of the semi-Lagrangian trajectories is implemented in the ensemble weather prediction system based on the global atmosphere model SL-AV20 with a horizontal ...resolution of approximately 20 km, 51 vertical levels, and Local Ensemble Transform Kalman Filter (LETKF). The combined use of methods for stochastic perturbation of trajectories and the parameters and tendencies of subgrid-scale processes parameterizations allows to generate ensembles with a larger spread compared to ensembles without stochastic perturbations of trajectories. An improvement in probabilistic estimates of the ensemble forecasts for various variables is shown. The comparison of two versions of ensemble prediction system is presented.
We present recent modifications of the SL-AV global atmosphere model parallel structure and algorithms. The modification of the hybridMPI+OpenMP parallelization structure as well as new parallel I/O ...system is described. The new multigrid algorithm for solving the linear algebraic equations systems arising from discretization at the reduced latitude-longitude grid is introduced and the convergence results for this method are presented.
According to recent investigations of nanoparticular carrier systems the mode of drug-particle interaction appears to influence drug penetration into the skin. For a more detailed insight into the ...molecular structure of drug loaded particles the two independent analytical methods, namely the parelectric spectroscopy (PS) and the electron spin resonance (ESR) have been applied to 4,5,5,-trimethyl-1-yloxy-3-imidazoline-2-spiro-3′-(5′
⁎-cholestane) as a model drug. Spectra have been analyzed in dependence on the concentration of the spin label. Changes in the concentration-dependent dipole mobility and dipole density given by PS and the concentration-dependent rotational correlation time (ESR) which are a measure of the vicinity of carrier and/or the surfactant and guest molecule were studied with cholestane-labeled solid lipid nanoparticles (SLN), nanoparticular lipid carriers (NLC) and nanoemulsions (NE). The spin probes were attached to the SLN surface which consists of two distinct sub-compartments: the rim and the flat surface of the disk-like shapes. The shape could be observed by freeze-fraction electron microscopy. Spin probes, however, were incorporated into the carrier matrix in the cases of NLC and NE. Results of PS are verified by ESR which allows a more detailed insight. Taking the results together a detailed new model of ‘drug’-particle interaction could be established.
Algorithms for stochastic perturbation of parameters and tendencies of physical parameterizations for subgrid-scale processes are implemented into the ensemble prediction system. This system is based ...on the global semi-Lagrangian atmospheric model SL-AV with the resolution of 0.9 × 0.72 degrees in longitude and latitude, respectively, 96 vertical levels, and our implementation of the Local Ensemble Tranform Kalman Filter (LETKF). The use of stochastically perturbed parameterizations allows to generate ensembles with a significantly larger spread compared to one obtained with the method of static parameter perturbation. An improvement in the probabilistic estimates of the ensemble forecast for different seasons is shown.
PDF
