The MORSE group is currently looking for high quality PhD candidates to join us. Fully funded PhD positions available. Contact us for more info.
1. Enviro-Metrology: Next-Generation Optical Technology for Marine Science
Applications of advanced techniques in optical metrology to the environmental sciences is a growing field of research. Examples include new methods for measuring absorption and scattering phase functions in complex media such as aerosols and hydrosols. Such measurements provide a necessary foundation for the accurate modelling of radiative forcing of the atmosphere and ocean, and play a crucial role in understanding the response of planetary systems to climate change. The specific focus of this project is the remote sensing of marine ecosystems.
Ocean Colour Remote Sensing (OCRS) has transformed our knowledge of coupled physical and biogeochemical systems in marine waters. However, much of this advance has been based on qualitative observations and significant problems persist for obtaining truly quantitative data, particularly for optically complex coastal waters. The Marine Optics and Remote Sensing Group at the University of Strathclyde is leading a physics-based approach to this problem that uses established radiative transfer modelling techniques as the basis for new algorithm development. The quality of measured optical properties (absorption, attenuation, backscattering) of natural samples is currently the limiting factor for this approach. New measurement techniques are emerging that eliminate or greatly reduce the systematic errors that hinder existing methods.
This project will combine development and deployment of next-generation measurement technology (e.g. Point Source Integrating Cavity Absorption Meter and Hyperspectral Attenuation Meter) with modelling of sensor performance and effect on radiative transfer calculations to assess potential impact on our ability to accurately simulate OCRS signals. A key question to be addressed is: How accurately do we need to measure optical parameters for OCRS applications? The results of the project will feed directly into new OCRS algorithm development and will significantly advance Marine Optics as a quantitative science. There will be opportunity to explore Knowledge Transfer opportunities through existing links with ARGANS UK Ltd and the European Space Agency and with the Helmholtz-Zentrum Geesthacht (Germany). The student will have access to a unique laboratory environment through our participation in the Ultrafast Advanced Spectroscopy Shared Facility (McKee Co-PI with Neil Hunt) bringing new technology in the form of state of the art tuneable lasers and high-end spectrometer systems.
2. Optical properties of complex particle populations in dynamic coastal waters
The scattering of solar illumination by seawater plays a key role in placing physical limits on underwater visibility and imaging, determining the albedo of the world’s oceans (which comprise over two thirds of the surface of the planet) and generating the water-leaving radiance signals which are used in the satellite remote sensing of oceanic processes. The physical basis of scattering by pure seawater was established by Einstein (after false starts by Hooke, Tyndall, Rayleigh and others) but the contribution of suspended particles to scattering in natural waters is surprisingly resistant to theoretical modelling. It also poses serious challenges to traditional measurement methods which are currently being overcome by a combination of new laser-based instruments for determining scattering phase functions and recent innovations in submersible micro-holography.
The ocean contains an enormous array of suspended particles ranging from tiny submicron particles such as colloids, viruses and bacteria, through intermediate size classes such as pico- nano- and micro-plankton, up to millimetre sized complex aggregates and flocs. Each of these materials presents an optical scattering signal that contributes to both in situ measurements of scattering, backscattering and attenuation, but also to ocean colour remote sensing signals. Understanding the differential impact of each of these classes of materials on optical signals is therefore key to developing strategies for monitoring particle dynamics in the marine environment.
This studentship will build on work currently being carried out on a NERC-funded (£1.05m FEC, McKee Co-PI) collaborative project with the Universities of Bangor and Plymouth. The student will participate in later stages of data collection for the project, gaining access to state of the art instrumentation including underwater digital holography sensors to measure complex particle size and shape down to submicron sizes, and associated scattering signals from in situ attenuation and backscattering meters. These will be accompanied by hyperspectral radiometry profiles enabling linkage to ocean colour remote sensing applications, and by joint measurements of angle-resolved phase functions carried out in collaboration with colleagues at the Laboratoire d’Oceanographie de Villefranche. The student will have an opportunity to work on a unique and ground breaking data set that will support development of new physical models to describe the scattering properties of complex distributions of particles including aggregates. The effects of turbulent shear on aggregate size and shape will be investigated through tank-based and in situ experiments.
Candidates should have a strong background (Ist Class Honours or equivalent) in Physics, Oceanography or another numerate discipline. Experience of working with experimental apparatus and / or modelling software would be advantageous.
