China
Africa
Explore chapters and articles related to this topic
Environmental Models in DEVS
Published in Gabriel A. Wainer, Pieter J. Mosterman, Discrete-Event Modeling and Simulation, 2018
Jean-Baptiste Filippi, Teruhisa Komatsu, David R.C. Hill
The coupling of the algae model is presented in Figure 14.7. There are a fixed number of particles for each simulation; all particles are contained in a coupled ocean model. In these simulations, an experiment is performed for a given set of ocean flow data. The experimental frame generator is linked to each particle as a broker of localized inputs. Flow data is interpolated at the very location of the particle using a bi-cubic method from matrices available from the OFES (Ocean general circulation model For the Earth Simulator) current simulation model [24]. These inputs are processed by a particle in a floating state to perform the integration of their advance in the flow.
Slowly Oscillates the Pacific
Published in Vikram M. Mehta, Natural Decadal Climate Variability, 2020
Beginning in late 1990s CE, there were several studies with idealized ocean models or ocean general circulation models to estimate contributions to tropical Pacific SST changes due to the v′Ty (Kleeman et al., 1999; Klinger et al., 2002; Nonaka et al., 2002; Solomon et al., 2003) and VT′y (Giese et al., 2002) processes. A study with a coupled ocean–atmosphere model (Merryfield and Boer, 2005) investigated the relative roles of these two processes and found that the v′Ty process was much more important. Yang et al. (2004) found that both processes associated with STCs in an ocean general circulation model contributed equally. Then, Lohmann and Latif (2005) addressed mechanisms of the observed decadal SST variability in central and western tropical Pacific with an ocean general circulation model forced with winds from the NCEP-NCAR reanalysis from 1948 to 2001 CE, and with a free-running, global coupled ocean–atmosphere model. Details of both sets of results are described and discussed by Lohmann and Latif (2005), so only highlights of relationships between decadal SST variability in the central and western equatorial Pacific region and meridional ocean circulations are described here. In experiments with the ocean-only model forced by the NCEP-NCAR reanalysis data, they found that anomalous mass transported by tropical cells between 5°N and 5°S latitudes in the upper 250 m in the Pacific Ocean had a generally opposite phase compared to SST anomalies such that SST anomalies were cooler (warmer) when the tropical cells were stronger (weaker) confirming that the v′Ty process played a very important role (Figure 1 in Lohmann and Latif (2005)). The tropical cell strength led the SST anomaly by a few months, implying that variability of the tropical circulations was driving the SST variability. Strengths of STCs, whose ambit was defined in this study as poleward of 10° latitude, were also found to vary inversely with the decadal SST anomalies but leading by 15 months. In general, the lag between meridional circulation changes and SST changes was found to increase with increasing latitude up to 15°, beyond which the correlation between the two became insignificant. In their free-running global coupled model, Lohmann and Latif (2005) also found that central and western equatorial Pacific SST varied with an opposite phase to that of strengths of tropical cells and STCs (Figure 9 in Lohmann and Latif (2005)).
Surface currents in operational oceanography: Key applications, mechanisms, and methods
Published in Journal of Operational Oceanography, 2023
Johannes Röhrs, Graig Sutherland, Gus Jeans, Michael Bedington, Ann Kristin Sperrevik, Knut-Frode Dagestad, Yvonne Gusdal, Cecilie Mauritzen, Andrew Dale, Joseph H. LaCasce
Ocean general circulation models (OGCMs) provide continuous fields of ocean currents, temperature and salinity through discretisation of physical laws. These are conservation of momentum, conservation of mass, and the laws of thermodynamics (Griffies 2004; Roed 2018). Discretisation occurs horizontally on a scale of metres to kilometres, and vertically on a scale of centimetres to metres. Figure 6 shows an example of surface currents from an OGCM with 2.4 km horizontal resolution. This resolution permits the existence of baroclinc eddies, though their generation processes are not fully resolved.
Coastal modelling incorporating artificial neural networks for improved velocity prediction
Published in ISH Journal of Hydraulic Engineering, 2022
Dhanya Sumangala, Hari Warrior
So the problem of modeling far-shelf velocities becomes more complicated as we go further away from the coast. The procedure of modeling the velocities is mostly answered by using numerical Ocean General Circulation Models. But due to the daunting task of solving these time-consuming equations, in this paper, we are opting for the augmenting of Delft3D with a data processing technique, the ANN.