James Cook University Australia

TNQ Drought Hub Scholarships

The TNQ Drought Hub is encouraging and supporting honours students through scholarships (full time and top-up) to conduct regionally focused drought resilience projects that will build academic knowledge in the agricultural sector.

Using Hyperspectral Satellite Remote Sensing to Assess Coral Reef Health and Predict Climate-Driven Vulnerability

Student: Sofie Boggio Sells
Academic Supervisor: Dr. Ben Jarihani

Research Questions/Objectives:

  1. How accurately can hyperspectral satellite data detect early stress signals in coral reefs, including bleaching precursors, shifts in pigmentation, and physiological decline?
  2. Can hyperspectral signatures be used to model drought-related marine heatwave risk and identify reefs most vulnerable to climate-induced stress?
  3. What remote-sensing indicators best correlate with in-water ecological metrics, such as coral cover, chlorophyll concentration, and reef structural complexity?
  4. How can satellite-derived indices improve preparedness and resilience planning for marine ecosystems affected by warming, drought, and associated environmental stressors?

Brief Description of the Project:

This project will integrate hyperspectral satellite imagery with in-water ecological data to evaluate coral reef health and identify early indicators of climate-driven stress. By leveraging the fine spectral resolution of new-generation hyperspectral platforms, the research will develop spectral indices specific to coral physiology, including pigment breakdown, symbiont loss, and changes in photosynthetic efficiency.

Spatial and temporal analyses will be used to map stress hotspots across selected reef systems, and to assess how drought-related climatic drivers, particularly elevated sea surface temperature, reduced cloud cover, and prolonged calm conditions—contribute to bleaching risk. The project will deliver a remote-sensing workflow for reef vulnerability assessment, providing tools valuable for early-warning systems and conservation management.

Background and Significance of the Research Question to drought risk, vulnerability, preparedness, or resilience:

Although drought is typically conceptualised as a terrestrial phenomenon, marine drought analogues, including anomalously dry, hot, cloud-free conditions, have profound impacts on coral ecosystems. These patterns drive marine heatwaves, increased irradiance, reduced water mixing, and subsequent coral bleaching. Understanding and predicting reef vulnerability under these conditions is essential for climate adaptation.

Hyperspectral satellites offer unprecedented opportunities for monitoring reefs at scale. Their ability to capture subtle spectral changes allows for early detection of bleaching precursors, sometimes before they are visually apparent. Implementing this technology contributes to:

  • Drought and heatwave preparedness by detecting early stress signatures.
  • Vulnerability assessment of reefs facing compounding climatic pressures.
  • Resilience planning by identifying refugia and prioritising management interventions.

This research aligns with broader climate resilience goals by providing a data-driven, scalable method for anticipating and mitigating the impacts of drought-related environmental stress on coral reef systems.

Academic and research experience relevant to the honours project:

I bring a combination of marine science field skills, geospatial innovation, and international research engagement that directly supports an honours project focused on hyperspectral satellites and coral resilience.

  1. PMRF Pipeline Project – Selected by OCEANX, One of the Most Prestigious Global Marine Programs

I am leading the PMRF pipeline project, a research initiative that was selected by OCEANX out of thousands of global applicants—a recognition reserved for only the most innovative and high-impact marine science proposals in the world.

OceanX is internationally renowned for advancing ocean exploration, high-resolution imaging, and scientific discovery alongside leading research institutions and global conservation partners. Being chosen by OceanX places the PMRF pipeline among a small group of projects considered capable of driving the next generation of ocean-science breakthroughs.

Our work focuses on developing advanced monitoring and assessment frameworks for coral reef ecosystems, integrating ecological surveys, imaging technologies, and data-driven diagnostic tools. My involvement in this project has allowed me to contribute to:

  • Developing new methodologies for climate-stress detection on coral reefs
  • Field-based coral health assessments and ecological data collection
  • Translating scientific insights into tools usable by conservation practitioners
  • Collaborating with an internationally curated cohort of scientists selected for excellence

Being part of an OceanX-selected project highlights my ability to contribute to research recognised at the highest level of global marine science, and it directly aligns with the cutting-edge nature required for an honours project using hyperspectral satellites for coral-reef resilience.

  1. Green LiDAR Coastal Mapping Project – Representing JCU College & the Drought Hub Internationally

I presented a Green LiDAR habitat-mapping project at an international research forum in Singapore, where I represented James Cook University’s College of Science and Engineering and the Northern Queensland Drought Resilience Adoption and Innovation Hub (Drought Hub).

Green LiDAR offers a non-invasive, high-resolution solution for mapping shallow-water ecosystems, capturing benthic structure and habitat complexity essential for assessing climate vulnerability.

My presentation at this global event showcased JCU’s innovation in combining:

  • Drone-based remote sensing
  • Coastal habitat modelling
  • Climate resilience applications

This opportunity demonstrated my capacity to communicate advanced geospatial concepts and contribute meaningfully to the international scientific community.

Principal Supervisor’s skills and experience in relation to this project topic:

Dr. Ben Jarihani is an expert in hydrology, remote sensing, environmental modelling, and geospatial analysis, with extensive experience applying Earth-observation technologies to ecological and environmental risk assessment. His work frequently involves integrating satellite imagery, field observations, and modelling to address questions related to climate impacts and environmental resilience.

His expertise in hyperspectral analysis, drought monitoring, and environmental hazard assessment makes him well-suited to supervise a project that bridges satellite remote sensing with climate-driven vulnerability studies in coral reef ecosystems. His guidance will be critical for building a robust methodological framework, ensuring strong analytical rigour, and linking scientific insight to real-world resilience strategies.

About me

I was born in Turin, Italy, and I am currently studying environmental science at James Cook University in North Queensland. I completed a bachelor’s degree in marine science, where I developed a strong interest in how marine and terrestrial systems are connected. Through my studies, I became increasingly aware that processes occurring on land, such as land use, rainfall, and river runoff, can strongly influence coastal environments. Understanding how land and sea systems depend on one another has become a central motivation for my research.

My research focuses on water quality and sediment runoff from river catchments into the coastal waters of the Great Barrier Reef. Rainfall events and catchment conditions can transport large amounts of sediment through river systems, which eventually reach the coast and influence water clarity and ecosystem health. These processes demonstrate how closely connected landscapes, rivers, and coastal environments are. My work uses satellite remote sensing to monitor sediment plumes and track water-quality changes across large areas that are difficult to observe from the ground. I am interested in the potential of hyperspectral satellite technologies, which collect detailed spectral information and can improve our ability to detect and analyse environmental changes in complex coastal and catchment systems.

I chose this area of research because I am passionate about understanding environmental processes and using new technologies to observe them at scale. Remote sensing provides a powerful way to monitor how landscapes and water systems interact over time.

Future Career Goals:

In the future, I hope to pursue a career in environmental research that combines remote sensing and Earth observation to support better management of catchments, water resources, and connected coastal ecosystems.

Milestone 1

Relevance to TNQ Drought Hub and end-users

During drought, graziers across the Burdekin and Burdekin-Dry Tropics rely on natural water holes, river reaches, and farm dams as critical stock-water source, yet these are the same water bodies most vulnerable to algal blooms triggered by nutrient pulses following flood-drought cycles. Satellite-derived indicators of chlorophyll-a, turbidity, and dissolved organic matter can provide graziers and NRM groups with early warning of deteriorating water quality at a catchment-wide scale, at no marginal cost per observation, supporting timely decisions about stock movement and alternative water supply before conditions become critical. This research directly addresses that need by evaluating whether the new generation of hyperspectral satellites can deliver operationally reliable water quality information across the Burdekin region, the heart of the TNQ Hub’s extensive grazing priority area.

The research outputs are designed to be directly usable by Drought Hub stakeholders across the catchment-to-coast continuum:

  1. Irrigators and water-supply operators: satellite-derived indicators of turbidity, chlorophyll-a and dissolved organic matter in storage dams and river reaches, of operational value for drinking-water source assessment, stock-water suitability, and early warning of algal blooms.
  2. NRM bodies and catchment management organisations (NQ Dry Tropics, Terrain NRM, Reef Catchments): independent, repeatable, region-wide maps of sediment and CDOM at river-reach, sub-catchment and inshore-reef scales, complementing point-based monitoring and modelled estimates of catchment restoration outcomes.
  3. Reef 2050 Water Quality Improvement Plan and regulators: operational satellite indicators of how rivers and the inshore reef respond to upstream changes, year-by-year, at a fraction of the marginal cost of expanded in-situ sampling programs.

Project technical focus

This study investigates how the new generation of hyperspectral satellites can be used to monitor water quality in rivers and coastal areas. Specifically, it provides the first independent assessment of NASA’s hyperspectral PACE Ocean Colour Instrument (OCI), a new satellite sensor that captures detailed colour information from the ocean, for monitoring water quality in the Great Barrier Reef (GBR). OCI is benchmarked directly against the operational multispectral Sentinel-3 OLCI sensor currently used by the Marine Monitoring Program (MMP) in Queensland. The main objective is to understand whether OCI’s denser spectral sampling delivers a measurable retrieval benefit over OLCI in the turbid, optically complex inshore waters of the Burdekin River region for three key water-quality indicators: total suspended solids (TSS), chlorophyll-a (Chl-a), and coloured dissolved organic matter (CDOM).

The study focuses on the 2024 to 2025 Burdekin River wet season, which produced the largest daily river discharge since 2008 to 2009 (peaking in mid-February 2025). A harmonised reference dataset of 274 discrete in-situ water samples from the MMP supports the validation. Because both satellite sensors have a relatively coarse spatial resolution compared to the inshore sampling sites (OCI at 1 km and OLCI at 300 m), the methodological backbone is a scale-explicit matchup framework that classifies every satellite-to-in-situ pairing by data quality before any retrieval is attempted, and reports the strict-matchup count transparently.

Progress to date

 

  • Conducted a literature review of hyperspectral satellites for water-quality applications focusing on mission inventory, atmospheric corrections (AC) processors, retrieval algorithms, validation networks and identified the research gaps.
  • Started the Python processing pipeline to test on real PACE OCI Level 2 datasets, reading grouped NetCDF swath data, recovering physical reflectance, matching in-situ coordinates to pixels, decoding quality flags, and applying the Bailey and Werdell (2006) 3×3-window matchup logic.
  • A coverage survey across fourteen flood-window scenes and seventeen Burdekin sites confirms research feasibility: eight scenes yield usable matchups, concentrated at offshore and mid-shelf reef sites. Inshore creek mouths flag out almost everywhere exactly as the scale-explicit design predicted, confirming them as qualitative Tier C sites.
  • Worked through multiple scope decisions; confirmed final scope and methods (Burdekin-only as study area, OLCI + PACE OCI as sensors). Designed the Tier A/B/C matchup approach and started my analysis.

Next steps of this research

Phase 2 (Months 7–14) Complete the Tier A/B/C classification across all event windows and finalise the clean matchup set. Phase 3 (Months 15–20) Retrieve TSS, chlorophyll-a and CDOM from both sensors using established band-ratio / semi-analytical algorithms and quantify per-constituent accuracy against the MMP samples. Phase 4 (Months 21–23) Run the spectral-convolution experiment, degrading OCI spectra to OLCI bands to isolate the contribution of spectral resolution alone.

Figure 1: Ocean chlorophyll-a and sediment response to the 2024 to 2025 flood event. Panels (a) and (b) show NASA PACE OCI Level 2 chlorophyll-a retrievals on 16 and 19 February 2025; the red rectangles highlight the coastal areas where the sediment discharge is most intense. Panel (c) shows Sentinel-2A multispectral true colour imagery over the discharge zone, captured before (30 January 2025), during (13 February 2025) and after (5 March 2025) the main flood pulse.
Milestone 2

To be completed.