Physical Oceanography change
Oceans occupy almost 3/4th of the surface of our planet. They have profound impact on climate and weather. SAC has dedicated team of scientist and researcher for oceanography. The current research includes Advanced Ocean State Forecast (AOSF) using numerical models and space-borne observations, Ocean Process Studies, and development of Data Assimilation (DA) techniques.

1. Advanced Ocean State Forecasting
The centre, generates accurate and timely forecasts of ocean state using numerical models and DA methods. The Salient activities are given below:
  • SWAN/WAM based wave forecasting system (assimilating Altika data) routinely runs and alerts provided through MOSDAC website.
  • Data-assimilative circulation system using POM model also runs routinely and outputs are hosted on MOSDAC website.
  • Development of capability of setting up very-high resolution wave and circulation models.
  • Storm surge forecasts using ADCIRC is now operationally run to produce the surge forecasts for the coastal area.


Wave

Circulation

Storm Surge


High resolution Sea surface temperature and Salinity from MOM-3 model

2. Ocean Process Studies
The study of the ocean processes is crucial in understanding the ocean dynamics. Thus several process studies have been undertaken. Some of them are mentioned below:
  • Bio-Physical Coupling in Ocean Model is the new component that has been added to ocean research arena to study the bio-physical exchange mechanisms
  • Initiated research on prediction of El Nino using coupled models. Satellite data are used to study the role of oceans in cyclone activities during La Nina/El Nina times
  • Thermal fronts from GHRSST and INSAT-3D SST have been useful to study ocean mixing
  • AWARE demonstrated potential renewable energy resource derived from Jason-2 and Altika altimeters over Indian Ocean region and the product is hosted on MOSDAC website
  • Methodology developed to extract wind, wave and sea level from 40 Hz Altika waveform near the Indian mainland coastal region. Sample product is hosted on MOSDAC website
  • RISAT-1 data have been utilized to derive high wind condition during the cyclone and also ocean features like eddies and fronts. The study of the ocean processes is crucial in understanding the ocean dynamics. Several process studies have been undertaken


Winds over cyclone Megh from RISAT-1

RISAT-1 MRS data (January 2014

At Full Resolution(25m) Diameter of eddy is 6.5 km

3. Development of the Data Assimilation Techniques
Satellite data are backbone of the ocean research and forecasting. Some of the activities carried out at centre the field of DA in ocean models are summarized below:
  • Singular Evolutive Extended Kalman (SEEK) Filter implemented in a global ocean model to assimilate SARAL/AltiKa sea level and Aquarius salinity data.
  • The polynomial chaos and particle filter data assimilation techniques are implemented in the coupled bio-physical model.
  • SEEK filter algorithm tested and operationally implemented in Storm surge model.
  • Algorithm developed for Ensemble Optimal Interpolation technique for AOSF.

Impact on thermocline depth (D20)

Dotted : SD Dash-dotted: CC Red Dash: Obs

Coupled Bio-Physical Model