Validation of a hybrid coordinate ocean model for the Indian Ocean

George, Mary Swapna; Bertino, Laurent; Prof, O M Johannessen; Samuelsen, Annette

doi:10.1080/1755876x.2010.11020115

Cited by 19 publications

(11 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Multi-lateral efforts are being taken up by international scientific community to study the Indian Ocean, especially the basins of the northern Indian Oceanfor applications ranging widely from fishery resource management to weather research and forecasting (George et al 2010;Hyder et al 2012). These efforts heavily rely on satellite as well as model simulations for deeper understanding of the column properties, as well as oceanic processes.…”

Section: Resultsmentioning

confidence: 99%

Getting the right wind-forcing for an ecosystem model: A case study from the eastern Arabian Sea

Chakraborty

Nimit

Gupta

2017

Journal of Operational Oceanography

View full text Add to dashboard Cite

The state of the ocean simulated through a numerical model is extremely sensitive to the forcing and hence, the choice of appropriate forcing is essential, in particular wind-fields. We compared Regional Ocean Modeling System (ROMS) simulations when forced with two different wind-fields derived from satellite sensors (scatterometers), namely QuickSCAT and ASCAT, while keeping the remaining configurations the same. This study had been carried out during the operational overlapping period of these scatterometers (2007-2009). We observed that the simulations of upper ocean chlorophyll distribution and depth of sub-surface chlorophyll maximum were vastly diverging when the model was forced with different scatterometer forcings. In order to determine which of the forcings yielded coastal productivity closer to observations, we compared model-simulated upper ocean chlorophyll concentration with in situ observations along the eastern Arabian Sea. For all the sub-regions, the QuickSCAT wind-forced coastal productivity was better correlated with in situ chlorophyll than its counterpart. However, this signature was most prominent in the wind-driven upwelling regime of the southeastern Arabian Sea. Additionally, when compared with surface chlorophyll derived from SeaWiFS and MODIS-Aqua satellites, we found that the QuickSCAT simulated interannual variability was in better agreement in comparison to its counterpart.

show abstract

Section: Resultsmentioning

confidence: 99%

Getting the right wind-forcing for an ecosystem model: A case study from the eastern Arabian Sea

Chakraborty

Nimit

Gupta

2017

Journal of Operational Oceanography

View full text Add to dashboard Cite

show abstract

“…The outer boundary was forced with hourly tidal elevations predicted with the TPXO 7.2 global tide model [Egbert and Erofeeva, 2002] that were adjusted slightly (31.1) to match the observed water levels. Daily temperature and salinity from publicly available (1/128 resolution) hindcasts of the Hybrid Ocean Coordinate Model (HYCOM) [George et al, 2010] were also applied. A simplified southward-flowing mean Leeuwin Current of 0.11 m s 21 was also included as a sea surface height gradient with velocities that matched the corresponding mean velocity from the HYCOM model for June-July 2009.…”

Section: Model Descriptionmentioning

confidence: 99%

Wind and tidal mixing controls on stratification and dense water outflows in a large hypersaline bay

et al. 2015

View full text Add to dashboard Cite

In Shark Bay, a large inverse estuary in Western Australia, longitudinal density gradients establish a gravitational circulation that is important for Bay-ocean exchange and transport of biological material such as larvae. The relative contributions of energy from wind and tidal mixing on the control of vertical stratification and gravitational circulation were investigated using the three-dimensional baroclinic ocean circulation model (General Estuarine Transport Model, GETM). In this large inverse estuary, the effects of the winds and tides on vertical mixing were found to be of similar magnitude. A critical depth of 15 m was identified that determined whether winds or tides or a combination of the two was required to create vertically mixed conditions. Where it was shallower than the critical depth, either the wind or tide could fully mix the water column. In contrast, a combination of both winds and tides was required to mix the deeper channels. Density-driven circulation peaked 0-3 days after periods of maximum stratification, resulting in a fortnightly modulation of dense water outflows along the seabed following the tidal stage. Salt flux calculations provided new evidence for the predominance of outflow through the deeper northern entrance channel where outflows persisted through all stages of the tide. In contrast, outflows through the western channel were more intermittent with a stronger tidal component. Wind driven lateral circulation between the entrances was also important and could temporarily reverse the circulation during northerly wind events.

show abstract

“…AGU‐HYCOM (Backeberg et al, ) is a southern African regional configuration of the HYCOM (Bleck, ), with a domain of 10°–50°S, 0°–60°E, nested inside a basin‐scale HYCOM of the Indian and Southern Oceans (George et al, ). The inner AGU‐HYCOM nest received snapshot boundary conditions from the parent model every 6 hr in a one‐way nesting approach.…”

Section: Methodsmentioning

confidence: 99%

Agulhas Current Meanders Facilitate Shelf‐Slope Exchange on the Eastern Agulhas Bank

et al. 2018

View full text Add to dashboard Cite

Large solitary meanders are arguably the dominant mode of variability in the Agulhas Current. Observational studies have shown that these large meanders are associated with strong upwelling velocities and affect the shelf circulation for over 100 days per year. Here 10‐year time series from two ocean general circulation models are used to create a composite picture of the Agulhas Current and its interactions with the shelf circulation in meandering and nonmeandering modes. Both models show good agreement with the size, propagation speed, and frequency of observed meanders. These composite meanders are then used to examine the response of shelf waters to the onset of large meanders, with the use of model output enabling the dynamics at depth to be explored. Results show a composite mean warming of up to 3°C of depth‐averaged temperature along the shelf edge associated with an intrusion of the current jet onto the shelf driven by an intensification of the flow along the leading edge of large meanders. However, this intensification of flow results in cooling of bottom waters, driving cold events at the shelf break of <10°C at 100 m. Thus, the intensification of the current jet associated with large meander events appears to drive strong up and downwelling events across the inshore front of the Agulhas Current, facilitating shelf‐slope exchange.

show abstract

Validation of a hybrid coordinate ocean model for the Indian Ocean

Cited by 19 publications

References 26 publications

Getting the right wind-forcing for an ecosystem model: A case study from the eastern Arabian Sea

Getting the right wind-forcing for an ecosystem model: A case study from the eastern Arabian Sea

Wind and tidal mixing controls on stratification and dense water outflows in a large hypersaline bay

Agulhas Current Meanders Facilitate Shelf‐Slope Exchange on the Eastern Agulhas Bank

Contact Info

Product

Resources

About