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Cahalan, Robert

JCET Fellow

Departmental Affiliation:  Physics

JCET Research Group:  Climate and Radiation

GSFC Code:  613

Mailing Address:
NASA/Goddard Space Flight Center
Code 613
Greenbelt, MD 20771 USA

Phone:  (301) 614-6183

Robert Cahalan


Dr. Robert Cahalan is Head of the Climate and Radiation Branch at NASA’s Goddard Space Flight Center. He is also Visiting Senior Research Scientist at UMCP/ESSIC, Adjunct Professor of Physics at UMBC, and has been graduate advisor at universities in the USA, Canada, and the Netherlands, and Visiting Scientist at NCAR, Aspen Center for Physics, Institute of Theoretical Physics in Warsaw, and ECMWF in Reading, England.

Dr. Cahalan serves in several other key roles – as NASA representative to the U.S. Climate Change Science Program, where he chaired the Observations Working Group; Project Scientist of the International Intercomparison of 3D Radiation Codes (I3RC); Project Scientist for the NASA Solar Radiation and Climate Experiment (SORCE); Lead Scientist for the Thickness from Offbeam Returns (THOR) lidar system; Chair of the Goddard Sun-Climate Center; member of the Science Team of the Department of Energy Atmospheric Radiation Measurement (ARM) program, the NASA Landsat Science Team, and the MODIS Science Team. He has been recognized with prestigious national and international and awards, including the Outstanding Leadership and Service Award of the Climate Change Science Program; the NASA Exceptional Service Medal; the NASA Achievement Award; and the Goddard Achievement Award.  He currently serves as Acting Vice President of the International Radiation Commission and as Chair of the 3-Dimensional Radiative Transfer group.
Dr. Cahalan has authored and coauthored more than 85 refereed publications in physics, atmospheric sciences, climate, remote sensing, and Sun-Earth interactions.  He developed a technique termed the “independent pixel approximation” that is now used in many world-class global climate models and in remote sensing retrieval algorithms.  Another of Dr. Cahalan’s 1994 first author publications addressed 3-dimensional cloud effects, and now has 140 citations.  He gives many invited talks, often serves as convener and organizer of international meetings, and has initiated and chaired several international workshops.

Under his leadership during 2003-2006, the Observations Working Group (OWG) of the U.S. Climate Change Science Program (CCSP) was established, and has coordinated observational priorities for FY07 and beyond; additionally, the OWG contributed chapters on “Observing and Monitoring the Climate System” in three annual reports to Congress as part of the “Our Changing Planet” series.  Dr. Cahalan was lead author of a chapter and longer technical reference on climate as part of the “Strategic Plan for the US Integrated Earth Observation System,” which was approved by the White House and published by the National Science and Technology Council. Dr. Cahalan has been lead organizer of three public workshops on climate observations.

As OWG Chair, he provided oversight for development of a “simple maturity model” for evaluating the effectiveness of the integrated system of Earth observations, a tool was tested at a workshop of federal managers in 2006, and is now undergoing further testing and improvement.  These actions benefited the Climate Change Science Program by documenting for the U.S. Congress the government’s achievements in Earth observations, providing current and future priorities, and promoting development of new tools for evaluation and prioritization of future observations.  In recognition of his work, in 2006 Dr. Cahalan was awarded a medal for “Outstanding Leadership and Service” by Hon. James Mahoney, Assistant Secretary of Commerce for Oceans and Atmospheres.