Numerical Experiments with the Coupled Ocean-Earth-Atmosphere Circulation Model and the Analysis of Decadal Variability of Its Main Physical Characteristic

2019 ◽  
Author(s):  
Natalia Tuchkova ◽  
Konstantin Belyaev ◽  
Gury Mikhailov
Keyword(s):  
Physical Characteristic ◽  
Numerical Experiments ◽  
Decadal Variability ◽  
Circulation Model ◽  
Earth Atmosphere

Evaluating Effects of Observational Data Assimilation in General Ocean Circulation Model by Ensemble Kalman Filtering: Numerical Experiments with Synthetic Observations

2021 ◽  
pp. 50-66
Author(s):  
V. N. Stepanov ◽  
◽  
Yu. D. Resnyanskii ◽  
B. S. Strukov ◽  
A. A. Zelen’ko ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Observational Data ◽  
Ocean Circulation ◽  
Numerical Experiments ◽  
Turbulent Viscosity ◽  
Bottom Topography ◽  
Synthetic Data ◽  
Circulation Model ◽  
Ocean Model ◽  
Global Ocean

The quality of simulation of model fields is analyzed depending on the assimilation of various types of data using the PDAF software product assimilating synthetic data into the NEMO global ocean model. Several numerical experiments are performed to simulate the ocean–sea ice system. Initially, free model was run with different values of the coefficients of horizontal turbulent viscosity and diffusion, but with the same atmospheric forcing. The model output obtained with higher values of these coefficients was used to determine the first guess fields in subsequent experiments with data assimilation, while the model results with lower values of the coefficients were assumed to be true states, and a part of these results was used as synthetic observations. The results are analyzed that are assimilation of various types of observational data using the Kalman filter included through the PDAF to the NEMO model with real bottom topography. It is shown that a degree of improving model fields in the process of data assimilation is highly dependent on the structure of data at the input of the assimilation procedure.

Numerical Modeling of Bioluminescence Distributions in the Coastal Ocean*

2003 ◽  
Vol 20 (7) ◽  
pp. 1060-1068 ◽  
Author(s):  
Igor Shulman ◽  
Steven H. D. Haddock ◽  
Dennis J. McGillicuddy ◽  
Jeffrey D. Paduan ◽  
W. Paul Bissett
Keyword(s):  
Hydrodynamic Model ◽  
Numerical Experiments ◽  
Flow Direction ◽  
Circulation Model ◽  
Velocity Fields ◽  
Monterey Bay ◽  
Resolution Model ◽  
Tracer Distribution ◽  
Fine Resolution ◽  
Initialization Procedure

Abstract Bioluminescence (BL) predictability experiments (predictions of the intensity, depth, and distance offshore of the BL maximum) were conducted using an advective–diffusive tracer model with velocities and diffusivities from a fine-resolution model of the Monterey Bay, California, area. For tracer initialization, observations were assimilated into the tracer model while velocities and diffusivities were taken from the hydrodynamic model and kept unchanged during the initialization process. This dynamic initialization procedure provides an equilibrium tracer distribution that is balanced with the velocity and diffusivity fields from the hydrodynamic model. This equilibrium BL distribution was used as the initial BL field for 3 days of prognostic calculations. Two cross-shore surveys of bioluminescence data conducted at two locations (north of the bay and inside the bay) were used in four numerical experiments designed to estimate the limits of bioluminescence predictions by tracers. The cross-shore sections extended to around 25 km offshore, they were around 30 m deep, and on average they were approximately 35 km apart from each other. Bioluminescence predictability experiments demonstrated a strong utility of the tracer model (combined with limited bioluminescence observations and with the output from a circulation model) in predicting (over a 72-h period and over 25–35-km distances) the location and intensity of the BL maximum. Analysis of the model velocity fields and observed and model-predicted bioluminesence fields shows that the BL maximum is located in the frontal area representing a strong reversal of flow direction.

scholarly journals The dynamics of the Snowball Earth Hadley circulation for off-equatorial and seasonally-varying insolation

2013 ◽  
Vol 4 (2) ◽  
pp. 927-965 ◽  
Author(s):  
A. Voigt
Keyword(s):  
General Circulation ◽  
Circulation Model ◽  
Hadley Circulation ◽  
Momentum Transport ◽  
Snowball Earth ◽  
Earth Atmosphere ◽  
Mean Flow ◽  
Vertical Diffusion ◽  
Atmosphere General Circulation Model ◽  
Dry Convection

Abstract. I study the Hadley circulation of a completely ice-covered Snowball Earth through simulations with a comprehensive atmosphere general circulation model. Because the Snowball Earth atmosphere is an example of a dry atmosphere, these simulations allow me to test to what extent dry theories and idealized models capture the dynamics of dry Hadley circulations. Perpetual off-equatorial as well as seasonally-varying insolation is used, extending a previous study for perpetual on-equatorial (equinox) insolation. Vertical diffusion of momentum, representing the momentum transport of dry convection, is fundamental to the momentum budgets of both the winter and summer cells. In the zonal budget, it is the primary process balancing the Coriolis force. In the meridional budget, it mixes meridional momentum between the upper and the lower branch and thereby decelerates the circulation. Because of the latter, the circulation intensifies by a factor of three when vertical diffusion of momentum is suppressed. For seasonally-varying insolation, the circulation undergoes rapid transitions from the weak summer into the strong winter regime. Consistent with previous studies in idealized models, these transitions result from a mean-flow feedback, because of which they are insensitive to the treatment of vertical diffusion of momentum. Overall, the results corroborate previous findings for perpetual on-equatorial insolation. They demonstrate that an appropriate description of dry Hadley circulations, in particular their strength, needs to incorporate the vertical momentum transport by dry convection, a process that is neglected in most dry theories and idealized models. An improved estimate of the strength of the Snowball Earth Hadley circulation will also help to better constrain the climate of a possible Neoproterozoic Snowball Earth and its deglaciation threshold.

scholarly journals The typhoon-induced drying of the Maritime Continent

2020 ◽  
Vol 117 (8) ◽  
pp. 3983-3988 ◽  
Author(s):  
Enrico Scoccimarro ◽  
Silvio Gualdi ◽  
Alessio Bellucci ◽  
Daniele Peano ◽  
Annalisa Cherchi ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Numerical Experiments ◽  
General Circulation ◽  
Circulation Model ◽  
Circulation Pattern ◽  
Maritime Continent ◽  
Global Circulation ◽  
Global Atmospheric Circulation ◽  
Definition Of ◽  
Convective Condensation

The Maritime Continent plays a role in the global circulation pattern, due to the energy released by convective condensation over the region which influences the global atmospheric circulation. We demonstrate that tropical cyclones contribute to drying the Maritime Continent atmosphere, influencing the definition of the onset of the dry season. The process was investigated using observational data and reanalysis. Our findings were confirmed by numerical experiments using low- and high-resolution versions of the CMCC-CM2 General Circulation Model contributing to the HighResMIP CMIP6 effort.

scholarly journals The Oceanographic Multipurpose Software Environment

2016 ◽  
Author(s):  
Inti Pelupessy ◽  
Ben van Werkhoven ◽  
Arjen van Elteren ◽  
Jan Viebahn ◽  
Adam Candy ◽  
...  
Keyword(s):  
Numerical Experiments ◽  
High Performance ◽  
Rapid Development ◽  
Circulation Model ◽  
Simulation Models ◽  
Ocean Model ◽  
Propagation Model ◽  
Global Ocean ◽  
Global Circulation Model ◽  
Software Environment

Abstract. In this paper we present the Oceanographic Multipurpose Software Environment (OMUSE). This framework aims to provide a homogeneous environment for existing or newly developed numerical ocean simulation codes, simplifying their use and deployment. In this way, OMUSE facilitates the design of numerical experiments that combine ocean models representing different physics or spanning different ranges of physical scales. Rapid development of simulation models is made possible through the creation of simple high-level scripts, with the low-level core part of the abstraction designed to deploy these simulations efficiently on heterogeneous high performance computing resources. Cross-verification of simulation models with different codes and numerical methods is facilitated by the unified interface that OMUSE provides. Reproducibility in numerical experiments is fostered by allowing complex numerical experiments to be expressed in portable scripts that conform to a common OMUSE interface. Here, we present the design of OMUSE as well as the modules and model components currently included, which range from a simple conceptual quasi-geostrophic solver, to the global circulation model POP. We discuss the types of the couplings that can be implemented using OMUSE and present example applications, that demonstrate the efficient and relatively straightforward model initialisation and coupling within OMUSE. These also include the concurrent use of data analysis tools on a running model. We also give examples of multi-scale and multi-physics simulations by embedding a regional ocean model into a global ocean model, and in coupling a surface wave propagation model with a coastal circulation model.

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