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Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations 总被引：1，自引：1，他引：0
BENNY N. Peter SHENBAKAVALLI Ranjan MAZLAN Hashim MOHD Nadzri Re MOHD Razali Mahmud 《海洋学报(英文版)》2015,34(9):12-22
High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation. 相似文献
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The Paradigm pelagic food web organization in Antarctic waters is undergoing fundamental revision evidence that large fractions of material and energy flow through the microbial food web. because of the unique Antarctic ecosystem conditions, the microbial food web performs some roles that are fundamentally different from those in oligotrophic temperate and tropical waters: 1) during winter, bacterial production, at the expense of slow-turnover DOM (dissolved organic matter) from the previous summer, could be a significant factor in the survival of over wintering animal populations; 2) microbial regeneration of ammonium in nitrate-replete Antarctic waters may spare the reductants necessary for nitrate assimilation and thus enhance primary productivity of deep-mixed light-limited phytoplankton; and 3) the small diatoms and phytoflagellates which dominate the Antarctic pelagic primary production are apparently directly digestible by the metazoan herbivores, whereas cyanobacteria which dominate the primary productivity in lower latitude oligotrophic waters are not digestible by the metazoan herbivores. These roles performed by the microbial loop may, in part, explain why Antarctic waters, in contrast to the lower latitude oligotrophic waters, have high levels of tertiary productivity despite low primary productivity. 相似文献
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