Researchers within Southampton’s Geospatial team have developed an algorithm which enables satellites to measure the chlorophyll levels of plants from space. This data is then used to analyse the planet's health, and environmental changes brought on by the climate crisis.
“We utilise data from satellites to look into the condition of the environment and then how that changes over time,” explains Jadu Dash, Professor of Remote Sensing. Jadu led the research alongside colleagues Sir Paul Curran, Visiting Professor, and Booker Ogutu, Associate Professor in Remote Sensing.
Images from the European Space Agency’s (ESA) Sentinel satellite programme, which uses the Southampton team’s algorithm, provide the appropriate input data used to estimate the chlorophyll content of plants. This calculation is called the Terrestrial Chlorophyll Index (TCI).
Capturing chlorophyll levels from space
The more chlorophyll a plant has, the more actively the plant is photosynthesising, which indicates more dynamic green spaces and a healthier environment.
Chlorophyll emits a green light, which can be quantified by the satellite technology developed by Jadu’s team and recorded. This data is then used to analyse plant health and environmental changes.
Since its creation, this data has been used to assess the impact of environmental changes on communities and their crops around the world. It plays a key role in enabling organisations to respond to issues such as poor harvests and the impact of extreme weather.
Creating greener urban communities
The team are utilising this technology in India to explore the impact of rapid urbanisation on quality of life and identify how to create greener, healthier neighbourhoods.
Working with the Indian Institute of Technology and the Bhubaneswar Development Authority, Jadu and his colleagues are changing the urban planning process, and highlighting the need for a more focused approach.
“Things have changed quite a lot over the last 20 years, with cities and towns expanding, often doubling in size, and sometimes they're not properly planned in terms of prioritising the amount of green space people have access to,” explains Jadu.
“We looked into the impact of urbanisation and how it’s changing the heat of urban areas. The urban heat island effect is where, compared to the rural areas, the urban areas are much warmer, and that’s affecting the people living there.”
Jadu Dash, Professor of Remote Sensing
The key solution was to support the local planning authorities to create more green spaces, providing a local cooling effect and cleaner air.
Using long-term satellite records, the team demonstrated where the green spaces should be located. They also showed how much these spaces would help reduce the area's temperature and ability to capture carbon, therefore improving the quality of life for residents.
They also looked at data and population dynamics to ensure that the people most in need of these changes would be prioritised. This helped them to create a ranking system to be used by the authorities going into the future, empowering them to create greener, more sustainable urban communities. The system also gives them a better understanding of where and what to invest in.
Jadu and his team are influencing planning policies in these areas.
“At the moment, a lot of this policymaking is not driven by real data. We’re trying to provide information to develop a better policy at the local scale which fits the needs of the people rather than something quite generic,” he says.
“In the end, it will help everyone to have a better life.”
A global influence
This technology has been used in other areas, too. Jadu and his colleagues have used it to examine crop yield in Sub-Saharan Africa, comparing the impact of environmental changes on local agricultural production in different regions of the country.
Their work is even helping to tackle the problem of devastating sargassum seaweed in the Caribbean, Central America and West Africa – solving issues for and supporting the education of local communities.
For Jadu, his technology’s contribution to improving so many areas is enormously meaningful and made possible by the facilities at his fingertips.
“It's great when you see people using what you have been developing as a part of your research,” he says. “We are one of the strongest UK departments in remote sensing and Earth observation."
"When we bring everything together – high-performance computing, state-of-the-art laboratory and field equipment including spectroscopy, laser scanning, drones, and expertise – we can address much bigger challenges.”
Jadu Dash, Professor of Remote Sensing
Lead image credit: Sailesh Patnaik
