An EnOI Assimilation of Satellite Data in an Indian Ocean Circulation Model

2014 ◽  
Vol 52 (7) ◽  
pp. 4106-4111 ◽  
Author(s):  
Smitha Ratheesh ◽  
Rashmi Sharma ◽  
Sujit Basu
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Satellite Data ◽  
Circulation Model ◽  
Ocean Circulation Model

scholarly journals Large variability in continental shelf production of phytoplankton carbon revealed by satellite

2010 ◽  
Vol 7 (6) ◽  
pp. 8953-8978
Author(s):  
B. F. Jönsson ◽  
J. E. Salisbury ◽  
A. Mahadevan
Keyword(s):  
Ocean Circulation ◽  
Satellite Data ◽  
Gulf Of Maine ◽  
Spatial Scales ◽  
Light Attenuation ◽  
Satellite Image ◽  
Circulation Model ◽  
Ocean Circulation Model ◽  
Large Variability ◽  
Chl A

Abstract. We estimate the net production of phytoplankton in the Gulf of Maine (GoM) over a 3-year period using satellite ocean color data in conjunction with surface velocities from a high-resolution operational ocean circulation model. Chlorophyll (chl-a) and light attenuation (K490) products are combined with a carbon to chlorophyll model to estimate the phytoplankton carbon (PC) stock in the euphotic layer. A satellite-based productivity, termed NCPe in analogy with net community production (NCP), is derived by tracking changes in satellite-derived PC from one satellite image to the next, along water parcel trajectories calculated with surface velocities from the ocean circulation model. Such an along-trajectory analysis of satellite data discounts the effect of advection that would otherwise contribute to the temporal change between consecutive images viewed in the fixed reference frame. Our results show a high variability of up to ± 500 mg C m−2 d−1 in NCPe on spatial scales of 10–100 km. A region-wide median NCPe of 40–50 mg C m−2 d−1 is often prevalent in the Gulf, while blooms attain peak values of 400 mg C m−2 d−1 for a few days. The spatio-temporal variability of NCPe in this region, though conditioned by seasonality, is dominated by events lasting a few days, which if integrated, lead to large inter-annual variability in the annual carbon budget. This study is a step toward achieving synoptic and time-dependent estimates of oceanic productivity and NCP from satellite data.

Assimilation of satellite-derived ocean surface current in an Indian Ocean circulation model

2013 ◽  
Vol 4 (5) ◽  
pp. 475-484 ◽  
Author(s):  
Manisha Santoki ◽  
Smitha George ◽  
Rashmi Sharma ◽  
K. N. Joshipura ◽  
Sujit Basu
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Surface Current ◽  
Ocean Surface ◽  
Ocean Circulation Model ◽  
Ocean Surface Current

scholarly journals A numerical modelling study of the interannual variability in the Indian Ocean

MAUSAM ◽  
2022 ◽  
Vol 46 (4) ◽  
pp. 409-422
Author(s):  
S. K. BEHERA ◽  
P. S. SALVEKAR
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Southern Hemisphere ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Return Flow ◽  
Ocean Circulation Model ◽  
Upper Layer Circulation ◽  
African Coast ◽  
The Indian Ocean

A simple reductA1 gravity wind-driven ocean circulation model is used to study the interannual variability in the upper layer of the Indian Ocean (24°S-23°N and 3S°E-IIS0E). The monthly mean wind stress for the period 1977-1986 are used as a forcing in the model. The model reproduces most of the observed features of the annual cycle of the upper layer circulation in the Indian Ocean when was forced with the ten-year average monthly mean wind. The circulation features and the model upper layer thickness show considerable interannual variability in most part of the basin; in particular, the Somali Current, the basin wide southern hemisphere gyre, the Equatorial Currents and the gyres in the Bay of Bengal. Six consecutive years starting from 1978 to 1983 which include two bad monsoon years of 1979 and 1982 are chosen to study the interannual variability. February circulation field shows stronger Equatorial Counter Currents in bad monsoon years, whereas. the cunents north of Madagascar flowing up to the African coast are found to be stronger in good monsoon years. The southward return flow from the Southern Gyre in August is strong and more to southern latitudes in the bad monsoon years. The flow circulated eastward to form another eddy east of Southern Gyre. The basin wide gyre of the southern hemisphere (SH) shows less variability in two consecutive normal years than in contrasting years.      

scholarly journals Large variability in continental shelf production of phytoplankton carbon revealed by satellite

2011 ◽  
Vol 8 (5) ◽  
pp. 1213-1223 ◽  
Author(s):  
B. F. Jönsson ◽  
J. E. Salisbury ◽  
A. Mahadevan
Keyword(s):  
Ocean Circulation ◽  
Satellite Data ◽  
Gulf Of Maine ◽  
Spatial Scales ◽  
Light Attenuation ◽  
Satellite Image ◽  
Circulation Model ◽  
Ocean Circulation Model ◽  
Large Variability ◽  
Chl A

Abstract. We estimate the net production of phytoplankton in the Gulf of Maine (GoM) over a 3-yr period using satellite ocean color data in conjunction with surface velocities from a high-resolution operational ocean circulation model. Chlorophyll (Chl-a) and light attenuation (K490) products are combined with a carbon to chlorophyll model to estimate the phytoplankton carbon (PC) stock in the euphotic layer. A satellite-based productivity, termed NCPe in analogy with net community production (NCP), is derived by tracking changes in satellite-derived PC from one satellite image to the next, along water parcel trajectories calculated with surface velocities from the ocean circulation model. Such an along-trajectory analysis of satellite data discounts the effect of advection that would otherwise contribute to the temporal change between consecutive images viewed in the fixed reference frame. Our results show a high variability of up to ±500 mg C m−2 d−1 in NCPe on spatial scales of 10–100 km. A region-wide median NCPe of 40–50 mg C m−2 d−1 is often prevalent in the Gulf, while blooms attain peak values of 400 mg C m−2 d−1 for a few days. The spatio-temporal variability of NCPe in this region, though conditioned by seasonality, is dominated by events lasting a few days, which if integrated, lead to large inter-annual variability in the annual carbon budget. This study is a step toward achieving synoptic and time-dependent estimates of oceanic productivity and NCP from satellite data.

scholarly journals Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution

2006 ◽  
Vol 56 (5-6) ◽  
pp. 543-567 ◽  
Author(s):  
Barnier Bernard ◽  
Gurvan Madec ◽  
Thierry Penduff ◽  
Jean-Marc Molines ◽  
Anne-Marie Treguier ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Circulation Model ◽  
Global Ocean ◽  
Ocean Circulation Model ◽  
Advection Schemes ◽  
Global Ocean Circulation

scholarly journals Multi-grid algorithm for passive tracer transport in the NEMO ocean circulation model: a case study with the NEMO OGCM (version 3.6)

2020 ◽  
Vol 13 (11) ◽  
pp. 5465-5483
Author(s):  
Clément Bricaud ◽  
Julien Le Sommer ◽  
Gurvan Madec ◽  
Christophe Calone ◽  
Julie Deshayes ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
Passive Tracer ◽  
Tracer Transport ◽  
Ocean Circulation Model ◽  
Grid Algorithm

Abstract. Ocean biogeochemical models are key tools for both scientific and operational applications. Nevertheless the cost of these models is often expensive because of the large number of biogeochemical tracers. This has motivated the development of multi-grid approaches where ocean dynamics and tracer transport are computed on grids of different spatial resolution. However, existing multi-grid approaches to tracer transport in ocean modelling do not allow the computation of ocean dynamics and tracer transport simultaneously. This paper describes a new multi-grid approach developed for accelerating the computation of passive tracer transport in the Nucleus for European Modelling of the Ocean (NEMO) ocean circulation model. In practice, passive tracer transport is computed at runtime on a grid with coarser spatial resolution than the hydrodynamics, which reduces the CPU cost of computing the evolution of tracers. We describe the multi-grid algorithm, its practical implementation in the NEMO ocean model, and discuss its performance on the basis of a series of sensitivity experiments with global ocean model configurations. Our experiments confirm that the spatial resolution of hydrodynamical fields can be coarsened by a factor of 3 in both horizontal directions without significantly affecting the resolved passive tracer fields. Overall, the proposed algorithm yields a reduction by a factor of 7 of the overhead associated with running a full biogeochemical model like PISCES (with 24 passive tracers). Propositions for further reducing this cost without affecting the resolved solution are discussed.

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