EE Colloquium: Exploring 3+ shades of water color from space: A bit of history, status, and the future

Dr. Nima Pahlevan, remote sensing scientist, Science Systems and Applications Inc. (SSAI) at the Terrestrial Information Systems Lab of NASA Goddard Space Flight Center, will be the speaker.

Abstract: A half-century of satellite observations has enabled developing, testing, and validating novel methodologies for studying aquatic ecosystems across global inland and nearshore coastal waters. These studies typically range from assessing optically relevant water quality indicators (concentrations of sediment, pigments, dissolved organic matter) and water color, characterizing and mapping benthic compositions (corals, seagrass) in optically shallow waters, and detecting surface algae and emergent vegetation. In this talk, I will walk you through the history of aquatic remote sensing since the 1970s and how the current fleet of national and international spaceborne missions have been adopted by the water resource sector, fisheries, and coastal management to address the impacts of climate-driven events and/or human activities on freshwater and coastal ecosystems. Various key image processing components, including instrument calibration, compensation for atmospheric scattering/absorption, and retrieval algorithms, will be discussed. I will further explain how we leverage a class of neural networks, termed Mixture Density Networks, to advance the quality of aquatic science products (e.g., pigment concentration) from spectro-radiometric observations. As NASA and other international space agencies are formulating, implementing, and fabricating space-borne hyperspectral instruments, I will share my vision on how various observation modalities from myriads of platforms (e.g., in situ, low-altitude unmanned crafts, CubeSats) will further advance our understanding of unexplored aspects of global aquatic environments.   

Bio: Nima Pahlevan is a remote sensing scientist with Science Systems and Applications Inc. (SSAI) at the Terrestrial Information Systems Lab of NASA Goddard Space Flight Center (GSFC). He earned a Ph.D. in Imaging Science from Rochester Institute of Technology (RIT). Before joining GSFC in 2014, Dr. Pahlevan finished a two-year postdoctoral term working on in situ and satellite-based ocean color measurements at the University of Massachusetts Boston. His main area of research lies within the aquatic remote sensing domain with a focus on algorithm developments, atmospheric correction, calibration/validation, impacts of climate variability on water resources, harmful algal blooms (HABs), and the relevant applied science practices. Dr. Pahlevan is a member of Landsat, PACE, and Terra/Aqua/SNPP Science teams, participates in GEO AquaWatch activities, and contributes to the Surface Biology Geology (SBG) pre-formulation studies. Pahlevan’s primary focus is developing novel machine-learning models to generate globally robust aquatic science products (e.g., water quality indicators) from multispectral and hyperspectral instruments. The overarching goal is to deliver seamless products to end-users (e.g., aquatic scientists, water resource managers) to enable large-scale studies, and monitoring, of aquatic ecosystems. This is achieved through close collaborations with national and international partners for the global validation of products.