Zadovoljstvo nam je pozvati vas na 78. Fakultetski seminar 5. 11. 2025. u B3-47 u 13:15 na temu:
New Ways to Study Biological Productivity in the Ocean Using Satellite-Derived Data
koji će održati dr. Bror Jonsson s Institute for the Study of Earth, Oceans, and Space, University of New Hampshire iz Sjedinjenih Američkih Država.
Sažetak
One of the key properties to assess marine biological ecosystems and the carbon transfer in the ocean is Primary Production (PP) or the rate at with which phytoplankton convert CO2 to organic carbon. Current satellite-based methods to estimate PP have been instrumental in closing the global carbon budget and in improving biogeochemical models on seasonal to decadal timescales. However, an intensified interest in high-resolution modelling requires methods to assess biological processes on sub-seasonal timescales as well. To do this I will present three new approaches to estimate productivity from space: 1) Combine satellite-derived chlorophyll with simulated velocity fields to estimate primary production on hourly to seasonal timescales and directly calculate rates. 2) Use Random Forest (RF) Regression to estimate primary production and include depth as an input feature for depth-resolved predictions. 3) Present a novel statistical method called MOving Standard deviation Saturation (MOSS) that can estimate dominating timescales of variability in very sparse satellite-derived time series.
Kratki životopis
Bror F. Jönsson is a Research Assistant Professor at the University of New Hampshire. His research includes the interaction between physical and biological processes; how marine systems are controlled at different temporal and spatial scales; and how to best quantify carbon fluxes in marine ecosystems. One overarching question is how to combine ship observations inherently limited in time and space, high-frequency autonomous assets constrained by instrumentation and spatial coverage, and satellite data with unprecedented temporal and spatial coverage but challenged by sparsity due to cloudiness and limited to the surface ocean. To better understand ecosystem processes at multiple scales, in spite these challenges, he has developed methods and frameworks that are sufficiently flexible to incorporate information from disparate datasets. An example of such frameworks combines Lagrangian particle tracking with network theory to quantify how advection via surface currents connects different regions of the global ocean. He received a BS in Biology from Uppsala University and a PhD in Physical Oceanography from Stockholm University, Sweden.
