WAVETRISK-1.0: an adaptive wavelet hydrostatic dynamical core

Abstract. This paper presents the new adaptive dynamical core wavetrisk. The fundamental features of the wavelet-based adaptivity were developed for the shallow water equation on the β plane and extended to the icosahedral grid on the sphere in previous work by the authors. The three-dimensional dynamical core solves the compressible hydrostatic multilayer rotating shallow water equations on a multiscale dynamically adapted grid. The equations are discretized using a Lagrangian vertical coordinate version of the dynamico model. The horizontal computational grid is adapted at each time step to ensure a user-specified relative error in either the tendencies or the solution. The Lagrangian vertical grid is remapped using an arbitrary Lagrangian–Eulerian (ALE) algorithm onto the initial hybrid σ-pressure-based coordinates as necessary. The resulting grid is adapted horizontally but uniform over all vertical layers. Thus, the three-dimensional grid is a set of columns of varying sizes. The code is parallelized by domain decomposition using mpi, and the variables are stored in a hybrid data structure of dyadic quad trees and patches. A low-storage explicit fourth-order Runge–Kutta scheme is used for time integration. Validation results are presented for three standard dynamical core test cases: mountain-induced Rossby wave train, baroclinic instability of a jet stream and the Held and Suarez simplified general circulation model. The results confirm good strong parallel scaling and demonstrate that wavetrisk can achieve grid compression ratios of several hundred times compared with an equivalent static grid model.

Download Full-text

WAVETRISK-1.0: an adaptive wavelet hydrostatic dynamical core

10.5194/gmd-2019-102 ◽

2019 ◽

Author(s):

Nicholas K.-R. Kevlahan ◽

Thomas Dubos

Keyword(s):

Shallow Water ◽

General Circulation ◽

Wave Train ◽

Shallow Water Equation ◽

Three Dimensional ◽

Circulation Model ◽

Time Step ◽

Adaptive Wavelet ◽

Dynamical Core ◽

Vertical Coordinate

Abstract. This paper presents the new adaptive dynamical core wavetrisk. The fundamental features of the wavelet-based adaptivity were developed for the shallow water equation on the β-plane in Dubos and Kevlahan (2013) and extended to the icosahedral grid on the sphere in Aechtner et al. (2015). The three-dimensional dynamical core solves the compressible hydrostatic multilayer rotating shallow water equations on a multiscale dynamically adapted grid. The equations are discretized using a Lagrangian vertical coordinate version of dynamico introduced in Dubos et al. (2015). The horizontal computational grid is adapted at each time step to ensure a user-specified relative error in either the tendencies or the solution. The Lagrangian vertical grid is remapped using an adaptive Lagrangian-Eulerian (ALE) algorithm onto the initial hybrid σ pressure-based coordinates as necessary. The resulting grid is adapted horizontally, but uniform over all vertical layers. Thus, the three-dimensional grid is a set of columns of varying sizes. The code is parallelized by domain decomposition using mpi and the variables are stored in a hybrid data structure of dyadic quad trees and patches. A low storage explicit fourth order Runge-Kutta scheme is used for time integration. Validation results are presented for three standard dynamical core test cases: mountain-induced Rossby wave train, baroclinic instability of a jet stream and the Held and Suarez simplified general circulation model. The results confirm good strong parallel scaling and demonstrate that wavetrisk can achieve grid compression ratios of several hundred times compared with an equivalent static grid model.

Download Full-text

Block-structured adaptive meshes and reduced grids for atmospheric general circulation models

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2009.0150 ◽

2009 ◽

Vol 367 (1907) ◽

pp. 4497-4522 ◽

Cited By ~ 32

Author(s):

Christiane Jablonowski ◽

Robert C. Oehmke ◽

Quentin F. Stout

Keyword(s):

Shallow Water ◽

Finite Volume ◽

Adaptive Mesh Refinement ◽

General Circulation ◽

Three Dimensional ◽

Storm Track ◽

General Circulation Models ◽

Adaptive Meshes ◽

Dynamical Core ◽

Block Structured

Adaptive mesh refinement techniques offer a flexible framework for future variable-resolution climate and weather models since they can focus their computational mesh on certain geographical areas or atmospheric events. Adaptive meshes can also be used to coarsen a latitude–longitude grid in polar regions. This allows for the so-called reduced grid setups. A spherical, block-structured adaptive grid technique is applied to the Lin–Rood finite-volume dynamical core for weather and climate research. This hydrostatic dynamics package is based on a conservative and monotonic finite-volume discretization in flux form with vertically floating Lagrangian layers. The adaptive dynamical core is built upon a flexible latitude–longitude computational grid and tested in two- and three-dimensional model configurations. The discussion is focused on static mesh adaptations and reduced grids. The two-dimensional shallow water setup serves as an ideal testbed and allows the use of shallow water test cases like the advection of a cosine bell, moving vortices, a steady-state flow, the Rossby–Haurwitz wave or cross-polar flows. It is shown that reduced grid configurations are viable candidates for pure advection applications but should be used moderately in nonlinear simulations. In addition, static grid adaptations can be successfully used to resolve three-dimensional baroclinic waves in the storm-track region.

Download Full-text

Dynamical Core of an Atmospheric General Circulation Model on a Yin–Yang Grid

Monthly Weather Review ◽

10.1175/2010mwr3375.1 ◽

2010 ◽

Vol 138 (10) ◽

pp. 3988-4005 ◽

Cited By ~ 35

Author(s):

Yuya Baba ◽

Keiko Takahashi ◽

Takeshi Sugimura ◽

Koji Goto

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Atmospheric General Circulation Model ◽

Three Dimensional ◽

Circulation Model ◽

Flow Fields ◽

Water Model ◽

Dynamical Core ◽

Atmospheric General Circulation ◽

Yin Yang

Abstract The three-dimensional dynamical core of an atmospheric general circulation model employing Yin–Yang grid is developed and examined. Benchmark test cases based on the shallow-water model configuration are first performed to examine the validity of two-dimensional calculations. The experiments show that the model simulates reasonable flow fields with second-order accuracy. The model validation is then extended to three-dimensional features where the capability of the dynamical core on the Yin–Yang grid has not been tested before: the global mountain gravity wave, long-term integration, and life cycle experiments. The simulated flow fields are in good agreement with the results of original experiments in all three experiments. The sensitivity of the model flow field to the overset region is also tested. The experiments reveal that the presence of the overset region does not significantly affect the dynamics on both long and short time scales, if the number of overset grids is fixed to three and the high-order interpolation method is applied for data interpolation between the Yin–Yang grids.

Download Full-text

On the response of a three-dimensional general circulation model to imposed changes in the ozone distribution

Journal of Geophysical Research Atmospheres ◽

10.1029/97jd00529 ◽

1997 ◽

Vol 102 (D11) ◽

pp. 13051-13077 ◽

Cited By ~ 21

Author(s):

B. Christiansen ◽

A. Guldberg ◽

A. W. Hansen ◽

L. P. Riishøjgaard

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Three Dimensional ◽

Circulation Model ◽

Ozone Distribution

Download Full-text

Operational ocean models in the Adriatic Sea: a skill assessment

Ocean Science ◽

10.5194/os-4-61-2008 ◽

2008 ◽

Vol 4 (1) ◽

pp. 61-71 ◽

Cited By ~ 25

Author(s):

J. Chiggiato ◽

P. Oddo

Keyword(s):

General Circulation ◽

Mean Squared Error ◽

Three Dimensional ◽

Circulation Model ◽

Remote Sensing Data ◽

Skill Assessment ◽

Regional Models ◽

Operational Systems ◽

Forecasting System ◽

The Mediterranean

Abstract. In the framework of the Mediterranean Forecasting System (MFS) project, the performance of regional numerical ocean forecasting systems is assessed by means of model-model and model-data comparison. Three different operational systems considered in this study are: the Adriatic REGional Model (AREG); the Adriatic Regional Ocean Modelling System (AdriaROMS) and the Mediterranean Forecasting System General Circulation Model (MFS-GCM). AREG and AdriaROMS are regional implementations (with some dedicated variations) of POM and ROMS, respectively, while MFS-GCM is an OPA based system. The assessment is done through standard scores. In situ and remote sensing data are used to evaluate the system performance. In particular, a set of CTD measurements collected in the whole western Adriatic during January 2006 and one year of satellite derived sea surface temperature measurements (SST) allow to asses a full three-dimensional picture of the operational forecasting systems quality during January 2006 and to draw some preliminary considerations on the temporal fluctuation of scores estimated on surface quantities between summer 2005 and summer 2006. The regional systems share a negative bias in simulated temperature and salinity. Nonetheless, they outperform the MFS-GCM in the shallowest locations. Results on amplitude and phase errors are improved in areas shallower than 50 m, while degraded in deeper locations, where major models deficiencies are related to vertical mixing overestimation. In a basin-wide overview, the two regional models show differences in the local displacement of errors. In addition, in locations where the regional models are mutually correlated, the aggregated mean squared error was found to be smaller, that is a useful outcome of having several operational systems in the same region.

Download Full-text

IL-GLOBO (1.0) – integrated Lagrangian particle model and Eulerian general circulation model GLOBO: development of the vertical diffusion module

Geoscientific Model Development ◽

10.5194/gmd-7-2181-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 2181-2191 ◽

Cited By ~ 4

Author(s):

D. Rossi ◽

A. Maurizi

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Spline Interpolation ◽

Circulation Model ◽

Linear Interpolation ◽

Computational Time ◽

Integration Time ◽

Particle Model ◽

Vertical Diffusion ◽

Time Step

Abstract. The development and validation of the vertical diffusion module of IL-GLOBO, a Lagrangian transport model coupled online with the Eulerian general circulation model GLOBO, is described. The module simulates the effects of turbulence on particle motion by means of a Lagrangian stochastic model (LSM) consistently with the turbulent diffusion equation used in GLOBO. The implemented LSM integrates particle trajectories, using the native σ-hybrid coordinates of the Eulerian component, and fulfils the well-mixed condition (WMC) in the general case of a variable density profile. The module is validated through a series of 1-D offline numerical experiments by assessing its accuracy in maintaining an initially well-mixed distribution in the vertical. A dynamical time-step selection algorithm with constraints related to the shape of the diffusion coefficient profile is developed and discussed. Finally, the skills of a linear interpolation and a modified Akima spline interpolation method are compared, showing that both satisfy the WMC with significant differences in computational time. A preliminary run of the fully integrated 3-D model confirms the result only for the Akima interpolation scheme while the linear interpolation does not satisfy the WMC with a reasonable choice of the minimum integration time step.

Download Full-text

The role of non-linear terms in the shallow water equation with the application in three-dimensional tidal model of the Malacca Strait and Taylor's Problem in low geographical latitude

Continental Shelf Research ◽

10.1016/s0278-4343(00)00059-5 ◽

2000 ◽

Vol 20 (15) ◽

pp. 1965-1991 ◽

Cited By ~ 11

Author(s):

Syamsul Rizal

Keyword(s):

Shallow Water ◽

Shallow Water Equation ◽

Three Dimensional ◽

Tidal Model ◽

Geographical Latitude ◽

Non Linear ◽

Malacca Strait

Download Full-text

Meridionally Extending Anomalous Wave Train over Asia During Breaks in the Indian Summer Monsoon

Earth Systems and Environment ◽

10.1007/s41748-019-00119-8 ◽

2019 ◽

Vol 3 (3) ◽

pp. 353-366 ◽

Cited By ~ 3

Author(s):

Uppara Umakanth ◽

Ramesh K. Vellore ◽

R. Krishnan ◽

Ayantika Dey Choudhury ◽

Jagat S. H. Bisht ◽

...

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

General Circulation ◽

Wave Train ◽

Eastern China ◽

Circulation Model ◽

Cyclonic Circulation ◽

The Arctic ◽

Indian Landmass ◽

Central Eastern

Abstract Anomalous interactions between the Indian summer monsoon (ISM) circulation and subtropical westerlies are known to trigger breaks in the ISM on subseasonal time-scales, characterised by a pattern of suppressed rainfall over central-north India, and enhanced rainfall over the foothills of the central–eastern Himalayas (CEH). An intriguing feature during ISM breaks is the formation of a mid-tropospheric cyclonic circulation anomaly extending over the subtropical and mid-latitude areas of the Asian continent. This study investigates the mechanism of the aforesaid Asian continental mid-tropospheric cyclonic circulation (ACMCC) anomaly using observations and simplified model experiments. The results of our study indicate that the ACMCC during ISM breaks is part of a larger meridional wave train comprising of alternating anticyclonic and cyclonic anomalies that extend poleward from the monsoon region to the Arctic. A lead–lag analysis of mid-tropospheric circulation anomalies suggests that the meridional wave-train generation is linked to latent heating (LH) anomalies over the CEH foothills, Indo-China, and the Indian landmass during ISM breaks. By conducting sensitivity experiments using a simplified global atmospheric general circulation model forced with satellite-derived three-dimensional LH, it is demonstrated that the combined effects of the enhanced LH over the CEH foothills and Indo-China and decreased LH over the Indian landmass during ISM breaks are pivotal for generating the poleward extending meridional wave train and the ACMCC anomaly. At the same time, the spatial extent of the mid-latitude cyclonic anomaly over Far-East Asia is also influenced by the anomalous LH over central–eastern China. While the present findings provide interesting insights into the role of LH anomalies during ISM breaks on the poleward extending meridional wave train, the ACMCC anomaly is found to have important ramifications on the daily rainfall extremes over the Indo-China region. It is revealed from the present analysis that the frequency of extreme rainfall occurrences over Indo-China shows a twofold increase during ISM break periods as compared to active ISM conditions.

Download Full-text