Dr. Winston Prakash Ph.D. 

Personal Website

Decade of adventure as a scientist

I worked as a Satellite Remote Sensing scientist for about a decade and developed sophisticated applications such as monitoring tropical storms for disaster warning using satellite data .

Research Associate at Space Physics Laboratory, Vikram Sarabhai Space Centre, Indian Space Research Organization (From Nov., 1987 to Nov., 1991)

After successfully completing my Master degree in physics, I applied for the research fellowship award in the Space Physics Laboratory of India Space Research Organization. This award is open to all eligible students with masters degree in physics or space physics. After successfully completing the written exam and subsequent interview with scientists of Space Physics Laboratory, I was adjudged as a suitable candidate for that award. This award is been given to two outstanding students for a period of three years, once in every three years.

My initial assignment was to work with engineers that built the SODAR (Sonic Detection And Ranging) and Meteorological Tower based Instrumentation. After understanding the nature and format of data recorded on tapes my next assignment was to develop software to analyze the data. Since these instruments were developed in-house, no software was available at that time.

I developed the following software

  • SODAR echo pattern visualization and analysis software.
  • Graphical representation of Fourier Spectra of Meteorological data obtained from Tower based instrumentation.
  • Software for statistical analysis of meteorological data and plotting them graphically

My scientific research work using these data and software resulted in several publications in reputed international journals and symposia. These publications are cited by others in their scientific publications.

Finally the dissertation, I wrote from the results of this scientific research has earned me my Ph.D. Degree in physics. (Synopsis)

As a Scientist at Meteorology and Oceanography Group, Space Applications Centre, Indian Space Research Organization, Ahmadabad. (From Nov., 1991 Oct. 1999)

After successfully completing my research fellowship, I applied for a scientific job at Meteorology and Oceanography Group (MOG) of Space Applications Center (SAC), which is one of the centers of Indian Space Research Organization (ISRO). MOG is dedicated to Satellite based remote sensing for meteorology and Oceanography studies. I was appointed as junior scientist on Nov. 1991. (Offer of appointment attached).

After joining MOG , within a short period, I became the co-investigator of project funded by European Space Agency (ESA). The satellite data required for this project was provided by ESA obtained from ERS series of satellites. Based on this research work, I was promoted to senior Scientist within two years of joining MOG and my name was published in the GAZETTE OF INDIA, EXTRAORDINARY Part 1 Section 2 on Jul. 1993 (Notification letter attached).

During my tenure as a scientist, I have completed the following projects successfully

  • Study of internal waves and their effect on coastal environment using Synthetic Aperture Radar (ERS – SAR)
  • Estimation of Ocean Surface Winds using Sun glitter seen in INSAT-VHRR images
  • Estimation of coastal wave energy from spectral estimates of ERS Altimeters and Wave Height data.
  • Extended Range Monsoon Prediction using Numerical model and Satellite Data

All the results from the above research works are published on various international journals and presented in symposia. Also these publications are cited by others in their scientific publications.

Indian Space Research Organization successfully launched series of geo-stationary satellites called Indian Satellite (INSAT) during early 1990. One of the payload of these satellites are VHHR used for satellite imaging of the earth for meteorological studies. However, since no software was readily available for analyzing these data, ISRO was depending on services from external agencies which proved very costly for ISRO. When the decision was made to develop in-house software, I took the responsibilities.

I developed the algorithm for geo-stationary satellite Image navigation and registration and they are published in computer and geosciences journal (see attachment 3 for listing). Also I designed and developed the complete software required for visual and empirical analysis of satellite images and complete satellite image processing software for pattern recognition and signature identification. (See my resume for details of software developed). This software is routinely used for Cyclone monitoring and monsoon progression monitoring in SAC, Gujarat, India.

Extended Range Monsoon Prediction

The Atmospheric Sciences Division has taken up the scientific problem of dynamical prediction of monsoon rainfall in monthly and seasonal scale over homogeneous rainfall regions of India. Being a member of the team I have done the following works.

  • Involved in numerical experiments with rainfall assimilation and deep convective scheme in simulating 1987 & 1988 summer monsoon rainfall. Analyzed the model output for diagnostic studies.
  • Developed tools for the diagnostic analysis of the output of the models (NCMRWF and CCM) used for extended Range Prediction.
  • Validating the monthly averaged surface fluxes with satellite based estimates using bulk aerodynamic methods.
  • Porting the NCMRWF medium range forecast model to sun-ultra computer system and developing the corresponding Post Processor for the model output analysis.
  • Retrieval and validation of land surface temperature from NOAA AVHRR images and computation of soil moisture from satellite and ground based measurements for physical initialization of the land surface parameterization scheme.

Internal Wave Studies

As co-investigator of the Department of Ocean Development sponsored project: "Remote sensing of internal waves in the ocean" and the European Space Agency approved project: "Study of ocean internal waves in ERS-1 SAR images", I have done the following work during this period.

  • Visual and Digital analysis of ERS-SAR, IRS-LISS, NOAA-AVHRR imageries of Andaman, Trivandrum, Goa coasts for delineating imageries containing Internal Wave Signatures.
  • Digital and spectral analysis of scenes containing the internal wave signatures to obtain the two dimensional characteristics such as wavelength, wave speed, propagation direction, region of generation, number of packets.
  • Studied the refraction and propagation of the internal waves in the Andaman Sea through a two dimensional internal wave refraction model and satellite based observations.

Sunglitter Studies

The specular reflection of sun by ocean surface seen in INSAT-VHRR visible band images is exploited for the extraction of ocean surface wind. The works completed are

  • A numerical algorithm based on reflection laws and Newton-Raphson iteration method to locate the principal specular point of sunglitter in VHRR images. This method is used for the automatic location and extraction of sunglitter from INSAT-VHRR images.
  • An algorithm based on modified orthographic projection to find the geo-location of pixels of geo-stationary satellite image, thus to register the image for basemap projection. This method is used for finding the geo-location of pixels in the VHRR corresponding to the sunglitter used in wind estimates.
  • A method based on Cox-Munk wave slopes and reflectance probability theory to estimate ocean surface wind speed from sunglitter signatures. Analyzed sunglint signatures in the INSAT-VHRR images over Arabian Sea and validated the results with climatology and GEOSAT altimeter derived wind speed.
  • A simulation study based on Satellite-Earth-Sun Geometry to explore the potential applications of simultaneous imaging of sunglitter by INSAT-1D & INSAT- 2A (located ~10o apart) in wind speed estimation and inter-comparison
Wave spectral studies

Using the estimated wave spectra from Synthetic Aperture Radar Images, wave energy and ocean bathymetry are inferred and validated against Naval Hydro-graphic Charts. The works completed are

  • Method to estimate the wavelengths of swells in the Indian Coastal region using two-dimensional spectral analysis.
  • Algorithm to estimate the coastal ocean depths from the wave spectra of swells using hydrodynamic methods.
  •  Estimation of wave energy from spectral estimates and ERS altimeter wind and wave height data
  • Developing a wave transformation model to estimate the wave power near the coastal regions