Upwelling along the coasts of Java and Sumatra and its relation to ENSO

R. Dwi Susanto,Arnold L. Gordon,Quanan Zheng,2001. Upwelling along the coasts of Java and Sumatra and its relation to ENSO. Geophysical Research Letters, Volume 28, Issue 8, pages 1599–1602, 15 April 2001.

Abstract

Upwelling along the Java-Sumatra Indian Ocean coasts is a response to regional winds associated with the monsoon climate. The upwelling center with low sea surface temperature migrates westward and toward the equator during the southeast monsoon (June to October). The migration path depends on the seasonal evolution of alongshore winds and latitudinal changes in the Coriolis parameter. Upwelling is eventually terminated due to the reversal of winds associated with the onset of the northwest monsoon and impingement of Indian Ocean equatorial Kelvin waves. Significant interannual variability of the Java-Sumatra upwelling is linked to ENSO through the Indonesian throughflow (ITF) and by anomalous easterly wind. During El Niño episodes, the Java-Sumatra upwelling extends in both time (into November) and space (closer to the equator). During El Nino (La Niña), the ITF carries colder (warmer) water shallowing (deepening) thermocline depth and enhancing (reducing) upwelling strength.

Keywords:

  • Information Related to Geographic Region: Indian Ocean
  • Oceanography: General: Equatorial oceanography
  • Oceanography: General: Upwelling and convergences
  • Oceanography: Physical: El Nino

Upwelling variability along the southern coast of Bali and in Nusa Tenggara waters

Nining Sari Ningsih,Noviani Rakhmaputeri,Agung B. Harto, 2013. Upwelling variability along the southern coast of Bali and in Nusa Tenggara waters. Ocean Science Journal, Volume 48, Issue 1, pp 49-57. DOI 10.1007/s12601-013-0004-3.

Abstract

Spatial and temporal variation of upwelling along the southern coast of Bali and in the Nusa Tenggara waters — Indonesia was studied by using satellite image data of sea surface temperatures and chlorophyll-a from September 1997 to December 2008. This study clearly reveals annual upwelling in the regions from June to October, associated with the southeast monsoon cycle, with the sea surface temperature (chlorophyll-a concentration) being colder (higher) than that during the northwest monsoon. In addition, this study also shows that the upwelling strength is controlled remotely by ENSO and IOD climate phenomena. During El Niño/positive IOD (La Niña/negative IOD) periods, the Bali — Nusa Tenggara upwelling strength increases (decreases).

Keywords:

  • upwelling
  • monsoon
  • ENSO
  • IOD
  • Bali-Nusa Tenggara

Upwelling induced by meso-scale cyclonic eddies in the Andaman Sea

Buranapratheprat, Anukul,Laongmanee, Penchan,Sukramongkol, Natinee,Prommas, Ritthirong,Promjunda, Sayan,Yanagi, Tetsuo, 2010. Upwelling induced by meso-scale cyclonic eddies in the Andaman Sea. Coastal marine science. Vol. 34, No. 1, 2010, pp. 68-73

http://hdl.handle.net/2261/51653

Abstract:

The results from a survey on oceanographic phenomena and fishery resources in the Andaman Sea, under the Ecosystem-Based Fishery Management in the Bay of Bengal Project, initiated by members of BIMSTEC (the Bay of Bengal Initiative for Multi-Sectoral Technical and Economic cooperation), revealed the evidence of upwelling. It was observed from shallow pycnocline and high salinity near sea surface. The relationship between surface chlorophyll-a (Chl-a) and upwelling was prominent that Chl-a tended to be high in upwelling areas. Satellite altimetry and the surface geostropic current captured during the same period of the field survey, suggest that upwelling is induced by cyclonic eddies. This phenomenon could be observed on satellite Chl-a image over the Andaman Sea. Further investigations are required to assess their role in oceanographic processes, especially primary productivity, in the Andaman Sea.

Keywords:

  • cyclonic eddy
  • upwelling
  • altimetry
  • geostrophic current
  • the Andaman Sea
  • nutrient
  • chlorophyll

Abnormal upwelling and chlorophyll-a concentration off South Vietnam in summer 2007

Liu, X., J. Wang, X. Cheng, and Y. Du (2012), Abnormal upwelling and chlorophyll-a concentration off South Vietnam in summer 2007, J. Geophys. Res., 117, C07021, doi:10.1029/2012JC008052.

Abstract

The present study investigates a strong upwelling and concurrent phytoplankton bloom off the South Vietnam coast in August 2007. Analysis of the alongshore wind, offshore Ekman transport, wind stress curl and other parameters indicates the southwesterly summer monsoon plays an important role in this peculiar case. The change of monsoonal wind involves variations of atmospheric circulation on multiple time scales. On the interannual time scale, a positive Indian Ocean Dipole (IOD) in 2007 accompanying with a La Niña event acts to enhance the southwesterly monsoon over the South China Sea (SCS). The enhanced southwesterly wind is regarded as a major factor in promoting the upwelling and the phytoplankton bloom off the South Vietnam coast. On the intraseasonal time scale, variations of the sea surface temperature (SST) and sea surface wind at 30-60 day periods reveal that the SST cooling develops with the evolution of the southwesterly wind anomalies with nearly one week delay, implying the great significance of the Madden-Julian Oscillation (MJO). Moreover, a tropical storm formed in the western SCS in early August reinforces the westerly wind and SST cooling. Among multiple factors on different time scales, the MJO event is considered as the major cause, since it induces the maximum velocity (4 m/s) of the southwesterly wind anomalies. As a result, the high Chlorophyll-a concentration (>0.56 mg/m3) and low SST center (<27 {degree sign}C) develops in the region off the South Vietnam coast and advects to the central SCS, riding on the northern rim of the southern anticyclonic gyre.

Keywords:

  • Chlorophyll-a concentration
  • El Niño
  • Indian Ocean dipole
  • Madden-Julian Oscillation
  • South Vietnam coast
  • upwelling