2025 Earth System Observations & Modeling Graduate Symposium 

Dr. Randal Koster: Dr. Koster has worked as a research scientist at NASA/GSFC since September of 1987.  Most of his tenure at GSFC has been dedicated to understanding and quantifying the contributions of land surface processes to meteorological predictability at subseasonal to seasonal timescales – an effort involving the development of improved treatments of land surface physics for atmospheric general circulation models and the analysis of the interactions between the land and atmosphere, using these models.  He is a Fellow of the American Meteorological Society and the American Geophysical Union (AGU), and this last year he was awarded AGU’s Peter S. Eagleson Hydrological Sciences Award.

Dr. Nachiketa Acharya: Nachiketa Acharya is an expert in statistical and machine learning modeling for weather and climate sciences, with over 15 years of experience, specializing in sub-seasonal to seasonal (S2S) forecasting. He currently serves as a Senior AI Weather and Climate Scientist at Spire, where he contributes to advancing AI-driven S2S forecasting. Throughout his career, he has held key positions at Lynker, NOAA's Earth System Research Laboratories and Office of Water Prediction, the University of Colorado Boulder, Penn State University, Columbia University, the City University of New York, the National Centre for Medium-Range Weather Forecasting in India, and the Indian Institute of Technology Delhi and Bhubaneswar. His work spans cutting-edge research, operational forecasting, and client/stakeholder engagement. He is an active member of the Artificial Intelligence Applications to Environmental Science and Probability and Statistics Committee at the American Meteorological Society. Additionally, he plays a significant role in Regional Climate Outlook Forums organized by the WMO, where he serves as an expert and trainer in S2S forecasting and verification.