Dr. Sorooshian's research focuses on surface hydrology, primarily in the area of rainfall-runoff modeling. He has devoted much of his effort to model identification and calibration issues and has developed special estimation criteria to account for the uncertainties of calibration data. Other research interests include the application of remote sensing data for characterization of hydrologic parameters and fluxes and the implication of climate variability and change in water resources. He also consults on problems related to surface hydrology and flood forecasting.

Dr. Sorooshian is a member of the National Academy of Engineering (NAE); Corresponding Member, International Academy of Astronautics (IAA); Fellow, American Association for the Advancement of Science (AAAS); Fellow, American Geophysical Union (AGU); Fellow, American Meteorological Society (AMS); Fellow, International Water Resources Association (IWRA); Chair, Science Steering Group (SSG) of Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Programme (WCRP); Member, UCAR Board of Trustees; Past-President of AGU's Hydrology Section; member of four editorial boards and former editor of AGU's Water Resources Research; Emeritus Member, NOAA Science Advisory Board; U.S. Member of the Hydrology Commission for WMO. He has served on numerous advisory committees, including those of NRC, NASA, NOAA, NSF, EPA, and UNESCO.

Professor Sorooshian delivered the William Nordberg Memorial Lecture at the Goddard Scientific Colloquium in 2004, and he is the recipient of the NASA Distinguished Public Service Medal, 2005 - "For your distinguished record in providing scientific leadership for global water cycle research and assuring that NASA science is well integrated into international programs."

In 2007, the United Nations Educational, Scientific and Cultural Organization (UNESCO) has named the Center for Hydrometeorology and Remote Sensing (CHRS) at UC Irvine and the National Science Foundation Science and Technology Center for Sustainability of Semi-arid Hydrology and Riparian Areas (SAHRA) at the University of Arizona joint winners of the 2007 Great Man-Made River International Water Prize.  Sorooshian was the founding director of SAHRA and is the founding director of the CHRS at The Henry Samueli School of Engineering at UC Irvine.  Presented biennially by the director-general of UNESCO, the prestigious Great Man-Made River Prize has only been awarded three times, in 2001 and 2005; this is the first time it has been awarded to U.S. institutions.

He was appointed to the Council in 2009.