24 Apr 2024

Soil sealing might not be a term that everyone's familiar with, but its effects are felt far and wide, particularly in urban areas.

Recognising the urgencies of addressing soil sealing and its associated challenges, an ESA-funded project, Ulysses, is offering insights into the extent and severity of soil sealing to mitigate soil degradation in the Mediterranean region.

Soil sealing refers to the process whereby soil surfaces are covered by impermeable materials such as concrete, asphalt or buildings, preventing water from infiltrating into the ground. This usually occurs in urban and industrial areas because of construction, car parks and other forms of development.

When soil is sealed, it loses its ability to absorb rainwater, leading to increased surface runoff and reduced groundwater recharge. This can contribute to various environmental problems, including flooding, soil erosion, loss of biodiversity and decreased soil fertility. Soil sealing also exacerbates the urban heat island effect by reducing the cooling effect of soil evaporation and vegetation.

Soil sealing monitoring is crucial, particularly for Mediterranean coastal areas, where soil degradation, combined with drought periods and fires, contributes to desertification risk.

That’s where the Ulysses project, or ESA Mediterranean Initiative, comes in. The project utilises Copernicus Sentinel-2 data to generate detailed maps depicting the extent and severity of soil sealing across the entire coastline of the Mediterranean Sea – enabling researchers to meticulously track changes in soil composition and permeability over time.

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(A) (B) Soil sealing over Barcelona

(C) (D) Soil sealing layer applied over Tunis