Dr. Jothiram Vivekanandan


Dr. Jothiram Vivekanandan (Vivek) is a Senior Scientist in Earth Observing Laboratory. Vivek’s research is centered on his pioneering effort to characterize the microphysics of clouds and precipitation using remote sensors. He is among a handful of researchers in the international community who mastered the theory, modeling, and observational aspects of atmospheric remote sensing. He has made significant contributions in applied research and technology transfer to the user community. The breadth of his research and development includes polarimetric radar, dual-wavelength radar, phased array radar, and lidar and microwave radiometer.

He is a Fellow of American Meteorological Society and serves an Associate Editor for the Radio Science and Chief executive editor of Geoscientific Instrumentation, Methods and Data Systems (GI) Journals.



Ground-based and Airborne Radars for Observing Clouds and Precipitation


The Earth Observing Laboratory (EOL) at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado develops and deploys a state-of-the-art ground-based radar and an airborne radar for detecting clouds and precipitation. The ground-based dual-polarization Doppler radar operates at S-band.  Polarimetric radar measurements are used for discrimination of hydrometeor particle types and estimating rain rate. Because the values of the radar observables that delineate different particle types overlap and are not sharply defined, the problem is well suited for a fuzzy logic approach. Retrieval of rain rate requires accurate radar measurements and a relation that relates radar observations to rain rate. Radar measurements of a thunderstorm, retrieved hydrometeor particle types, and rain rates will be presented.

            In order to record observations of clouds over the ocean and rugged mountainous terrain, NCAR/EOL is investigating potential configurations for the next generation airborne phased array radar (APAR) that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. The APAR will operate at C-band. A possible configuration of a dual-Doppler and polarimetric radar to be installed on an aircraft for retrieving 3-D winds, precipitation particle types, and rain rate will be described.